NOTIZIARIO Neutroni e Luce di Sincrotrone - Issue 7 n.2, 2002

Vol. 7 n. 2 Giugno 2002 - Aut. Trib. Roma n. 124/96 del 22-03-96 - Sped. Abb. Post. 70% Filiale di Roma - C.N.R. p.le A. Moro 7, 00185 Roma

NOTIZIARIONeutroni e Luce di Sincrotrone

Rivista delConsiglio Nazionaledelle Ricerche

ISSN 1592-7822

Cover photo:X-ray interference between the twoarrays of myosin heads in eachbipolar myosin filament superim-poses a finely spaced fringe patternonto the M3 X-ray reflection origi-nating from the ~14.5 nm axial re-peat of the myosin heads along thefilament. The effect is used to deter-mine with sub-nanometric precisionthe motions of myosin heads duringthe execution of the working strokethat drives force generation andsliding between actin and myosinfilaments in muscle contraction.

Il è pubblicato a

cura del C.N.R. in collaborazionecon il Dipartimento di Fisicadell’Università degli Studidi Roma “Tor Vergata”.

Vol. 7 n. 2 Giugno 2002Autorizzazione del Tribunale diRoma n. 124/96 del 22-03-96

DIRETTORE RESPONSABILE:

C. Andreani

COMITATO DI DIREZIONE:

M. Apice, P. Bosi

COMITATO DI REDAZIONE:

L. Avaldi, F. Aliotta,F. Carsughi, G. Ruocco.

SEGRETERIA DI REDAZIONE:

D. Catena

HANNO COLLABORATO

A QUESTO NUMERO:

F. Carsughi

GRAFICA E STAMPA:

om graficavia Fabrizio Luscino 7300174RomaFinito di stamparenel mese di Giugno 2002

PER NUMERI ARRETRATI:

Paola Bosi, Tel: +39 6 49932057Fax: +39 6 49932456E-mail: [email protected].

PER INFORMAZIONI EDITORIALI:

Desy Catena, Università degli Studidi Roma “Tor Vergata”, PresidenzaFacoltà di Scienze M.F.N., via dellaRicerca Scientifica, 1 00133 RomaTel: +39 6 72594100Fax: +39 6 2023507E-mail: [email protected]

Vol. 7 n. 2 Giugno 2002


SOMMARIO

Rivista delConsiglio Nazionaledelle Ricerche

EDITORIALE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2C. Andreani

RASSEGNA SCIENTIFICA

The ALOISA Beamline at ELETTRA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3F. Bruno et al.

Simulation of the Upgrade of the BackScattering Spectrometer IN13 at ILL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14C. Mondelli et al.

X-ray Interference Measures the Structural Changes of the Myosin Motor in Muscle with Å Resolution . . . 19M. Reconditi et al.

The Contribution of Neutron Scattering to Cultural Heritage Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30R. Rinaldi et al.

PROGETTO E.S.S. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

CALENDARIO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

VARIE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

SCADENZE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

FACILITIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43


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NOTIZIARIO NEUTRONI E LUCE DI SINCROTRONE • Vol. 7 n. 2 Giugno 2002

EDITORIALE

A partire da questo numero il dott. Franco Aliottaentra a far parte del Comitato di Redazione insostituzione del prof. Ulderico Wanderlingh.Ringrazio il collega Wanderlingh per l’attività

svolta in questi anni e mi auguro che la sua collaborazionecon il Notiziario continui. Nei primi mesi di quest’annonumerose sono state le iniziative in campo nazionale edinternazionale sia nel settore della luce di sincrotrone sia dineutroni. Nel primo caso la commissione Luce diSincrotrone dell’INFM ha deciso di sostenere le attività diricerca presso le linee sperimentali di ELETTRA ed ESRFdestinando nuovi finanziamenti sia per le missioni degliutenti sia per borse di dottorato e stages per visitingscientists. Un sostegno finanziario, quantificabile in circa300 kEuro/anno è anche previsto per i progetti PURS –Progetti Utilizzo Radiazione Sincrotrone – che prevedono losviluppo di strumentazione innovativa. Il Central Laboratory for the Research Council, CCLRC, edil Consiglio Nazionale delle Ricerche, CNR, hannorecentemente sottoscritto un nuovo accordo per l’utilizzodella sorgente di neutroni impulsati ISIS, confermando unacollaborazione tra i due enti, che originariamente risale al1985, nel settore della spettroscopia di muoni e neutroni.Questo accordo garantisce alla comunità italiana l’accessoalla sorgente ISIS per lo svolgimento di attività di ricercasperimentale e rappresenta una importante opportunità peril prosieguo della efficace collaborazione tra ricercatoribritannici ed italiani sia nella ricerca di base sia di sviluppodi strumentazione per muoni e neutroni.Segnaliamo inoltre che il progetto European SpallationSource, ESS, è stato presentato ufficialmente il 15-17Maggio a Bonn nella suggestiva sede del precedenteParlamento della Repubblica Federale di Germania.Informazioni sul progetto e sullo svolgimento dell’evento,che ha avuto una grande risonanza anche sui mezzi diinformazione, è disponibile sul sito webhttp://essnts.ess.kfa-juelich.de/Summary_conf/. Perquanto riguarda il progetto ESS durante l’ultimo ESSCouncil meeting tenutosi a Lund, Svezia, alla fine di Maggio,sia il CNR che il CCLRC hanno inoltre sottoscritto il nuovoMemorandum of Understanding. Durante la Conferenza di Bonn la Associazione diSpettroscopia di Neutroni Europea ha definito la nominadel suo nuovo presidente, prof. Fabrizio Barocchi, chepresiede anche la Società Italiana di SpettroscopiaNeutronica. A Fabrizio Barocchi indirizziamo i nostrimigliori auguri di un buon lavoro.Ricordiamo che all’Hotel Capo d’Orso - Località CalaCapra, Palau (SS) a Palau - nel periodo 23 settembre - 3ottobre 2002 si terrà la VI edizione della Scuola diSpettroscopia Neutronica ‘Francesco Paolo Ricci’. La scuolaavrà come tema ‘I neutroni come sonda microscopica disistemi disordinati’. Questa edizione sarà diretta dal dr.Ubaldo Bafile (CNR- Fisica Applicata ‘Nello Carrara’) e dalprof. Caterina Petrillo (Politecnico di Milano) e vedrà lapartecipazione di docenti dell’ILL (Grenoble), IRI (Delft),HMI (Berlino), Los Alamos (USA), CNR e Universitàitaliane. Gli studenti assisteranno a lezioni di teoria eparteciperanno ad attività sperimentali.

Starting from this issue the Editorial committee willbenefit from the scientific collaboration of dr.Franco Aliotta who substitutes prof. UldericoWanderlingh. I would like to thank Ulderico

Wanderlingh his work in these years and I hope that hiscollaboration with Notiziario will continue.In the first period of the year there have been severalinitiatives in the field of synchrotron radiation and neutronscattering in Europe and Italy. The INFM SynchrotronRadiation Board has decided additional support for theresearch activities based at ELETTRA and ESRF Large ScaleFacilities: This will include fundings for user missions,Doctoral fellowship and visiting scientist stages. A budgetof about 300 kEuro/year will also be devoted for specificprojects, named PURS-Progetti Utilizzo RadiazioneSincrotrone, addressed to the development of novelinstrumentation.The Central Laboratory for the Research Council, CCLRC,and the Italian National Research Council, CNR, haverecently agreed to continue the mutual scientificcollaboration, started in the year 1985, by signing a newagreement for the use of the pulsed neutron source ISIS.This initiative will guarantee, in the next years, to theneutron and muon scattering Italian community access toISIS source for scientific research. It also represents animportant opportunity for continuing the fruitful scientificcollaborations among the British and Italian communities,both in basic research and in the development of muon andneutron instrumentation.The ESS project proposal was presented officially at theEuropean Source of Science conference in Bonn, in theformer House of Parliament of the Federal Republic ofGermany from 15-17 May 2002. Information about the ESSproject and this event, which deserved much resonance onthe press, can be found at the web sitehttp://essnts.ess.kfa-juelich.de/Summary_conf/. Recentnews is also the decisions by CNR in Italy and CLRC in theUK to sign the new Memorandum of Understanding ESSwhich have been announced at the latest ESS Councilmeeting held in Lund, Sweden, late May. During the Bonn Conference the European NeutronScattering Association, ENSA, has also nominated its newPresident, prof. Fabrizio Barocchi, who is also chairing theItalian Neutron Scattering Society, SISN. A warm welcometo Fabrizio Barocchi and best wishes for a fruitful work. We recall that the VI edition of the Scuola di SpettroscopiaNeutronica ‘Francesco Paolo Ricci’ will be held in LocalitàCala Capra, Palau (SS), in the period September the 23th –October the 3rd. Theme of the school will be ‘The Neutronas a microscopic probe in disordered systems’. Directors ofthis edition will be dr. Ubaldo Bafile (CNR- Fisica Applicata‘Nello Carrara’) and prof. Caterina Petrillo (Politecnico diMilano). Teachers will come from ILL (Grenoble), IRI(Delft), HMI (Berlino), Los Alamos (USA), CNR and ItalianUniversities. Students will be attending lessons on neutronscattering theory and experimental activities.

Carla Andreani


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Vol. 7 n. 2 Giugno 2002 • NOTIZIARIO NEUTRONI E LUCE DI SINCROTRONE

AbstractThe ALOISA beamline at Elettra is dedicated to thestudy of the structural and chemical properties of solidsurfaces, interfaces and thin overlayers. The custom de-signed monochromator provides photons with high fluxand state of the art energy resolution in an energy rangefrom 150 to 8000 eV. The experimental chamber offersunique versatility in the choice of the detection setup,and the possibility to exploit different investigation tech-niques on the same system.We present here a short review of the beamline charac-teristics and a selection of representative experimentalresults describing the physical properties which can beinvestigated at ALOISA.

IntroductionThe chemical and magnetic properties of surfaces, over-layers and thin films are strongly correlated to their localgeometrical structure and long range morphology. Forthis reason, a spectroscopic study of surfaces has to beaccompanied by a structural characterization too. Ob-taining this complementary piece of information from insitu prepared systems is a difficult task since several ex-perimental techniques operating within the same appa-ratus are required. This possibility is offered by theALOISA (Advanced Line for Overlayer Interface andSurface Analysis) beamline of INFM (Istituto Nazionaleper la Fisica della Materia), operating at the Elettra stor-age ring[1]. The ALOISA beamline is designed to per-form photoelectron spectroscopy (XPS), absorption spec-troscopy, electron coincidence spectroscopy (APECS),photoelectron diffraction (PED), X-ray surface diffraction(XRD) and X-ray reflectivity (XRR) measurements. Forthis purpose, a monochromator covering a wide energyrange was developed and coupled to a dedicated wig-gler/undulator insertion device. The monochromatorcouples a plane mirror - plane grating dispersive systemfor the 150-2000 eV energy range to a Si(111) channel-cutcrystal for the 3 to 8 keV range. Aspherical optics wereadopted to reduce the number of optical elements. Thisoptical layout in sagittal focusing configuration togetherwith the absence of entrance slits fully exploits the excel-lent characteristics of the Elettra Synchrotron.

The main characteristics of ALOISA beamline can besummarized as follows:- a wide photon energy range (150 - 8000 eV)- high photon flux (1010 to 1011 ph/s at 0.02% band

width) and extremely high energy resolution of themonochromator in the low energy range (200 - 900 eV)

- possibility of studying the same system with differentspectroscopic and structural investigation techniquesin the same experimental chamber

- facilities for in situ preparation and monitoring ofoverlayer and thin film systems

- possibility of performing angle resolved multicoinci-dence (photoelectron - Auger electron) spectroscopyon surfaces (AR-APECS)

- wide range of available scattering geometries for un-conventional/novel use of the available experimentaltechniques.

HistoryIn 1996 the experimental chamber was tested includingthe 7 home designed electron analyzers mounted on twoindependently rotatable frames which, together with therotation of the whole experimental chamber, allows oneto freely explore the sky above the sample for any sur-face orientation with respect to the X-ray linear polariza-tion. The vacuum chambers of the monochromator weremounted at the end of the year. A preliminary alignmentwas performed by using a laser source placed inside themachine ring, which gave a rough alignment with the in-sertion device axis.The monochromator alignment was completed in 1997when a dimension of the beam focus at the exit slits of 20x 150 µm (FWHM) was obtained, in agreement with thedesign specifications. The refocusing mirror and the ex-perimental chamber were then placed accordingly in or-der to obtain the beam focus of 20 x150 µm in the centreof the experimental chamber. Along with the spatialbeam profile measurements, we also performed the en-ergy calibration and resolution analysis. Energy calibra-tion for various configurations of the PMGM assemblywas obtained by acquiring several gas absorption spec-tra and comparing them to the existing reference spectra.The photon flux impinging on the sample fulfilled the

THE ALOISA BEAMLINE AT ELETTRA

F.Bruno1,2, A.Cossaro1, D.Cvetko1,3, L.Floreano1, R.Got-ter1, A.Morgante1,2, G.Naletto6, A.Verdini1 , A.Ruocco5,A.Santaniello4, G.Stefani5, G.Tondello6 and F.Tommasi-ni1,2.1 Laboratorio TASC dell’Istituto Nazionale per la Fisica dellaMateria, S.S.14 Km 163.5, Basovizza, 34012 Trieste, Italy.

2 Dipartimento di Fisica dell’Università di Trieste, Italy.3 Department of Physics, University of Ljubljana, Slovenia.4 ELETTRA Sincrotrone Trieste, Trieste, Italy.5 Dipartimento di Fisica dell’Università di Roma 3, Italy.6 Dipartimento di Elettronica e Informatica dell’Università diPadova, Italy.

Articolo ricevuto in redazione nel mese di Maggio 2002

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design specifications largely exceeding 1010 ph/s at0.02% bandwidth. The world record resolution in the200-900 eV range was achieved in February. The crystalmonochromator was calibrated in the range 3000-8000eV by measuring solid state absorption spectra. The pho-ton flux was optimised in the whole energy range and itwas found to match the design values of 5x1010 ph/s onthe sample at the expected resolving power of 7500.The ALOISA beamline commissioning continued duringthe first two months of 1998. Surface X-ray diffractionpatterns have been measured on different reconstructedsurfaces by measuring the current on Si photodiodes.High intensity surface peaks were detected (up to 105

ph/s) for in-plane diffraction, while the detectionmethod was still limited for out-of-plane diffraction (rodscans) by low counting rates. In fact, the original UHV-compatible energy-resolved photon detector, operatingin counting mode, failed to meet the required perfor-mances.Since march 1998 the beamline is open to external users.During the year 1999 the available experimental tech-niques have been applied to different system to achievethe state of the art in their application. In particular, thepossibility to freely orient the detectors and the surfacewith respect to the photon beam polarization has beenexploited in backward scattering PED experiments to en-hance surface relaxation sensitivity, thus achieving bonddirection selectivity in measuring atomic distances andphotoelectron holography. The combination of forwardscattering PED and in-plane XRD has been put forwardto become a very effective procedure to study the grow-ing film structures. A major effort has been devoted tooptimize the control and acquisition software for PED,APECS and spectroscopy experiments.At the beginning of the year 2000 a new energy-resolvedphoton detector has been installed to replace the originalsystem so that out-of-plane XRD has become feasible,which finally completed the set of experimental tech-niques included in the original project. At the end of theyear, the vacuum components of the new HASPESbranch line have been delivered. During the followingyear the new Exit Slit chamber and the deflecting mirrorchamber have been installed and optically aligned witha laser.

Beamline characteristicsMonochromator performancesA schematic layout of the beamline optics is depicted inFig. 1. The monochromator is a slitless four optical ele-ment instrument. It is based on a plane mirror planegrating (PMPG) dispersive element for the low photonenergies (150-1500 eV) and on a Si(111) channel cut crys-tal dispersive element for the high energies (3-8 keV).The collimating, focusing (paraboloidal mirrors) and re-

focusing mirrors are placed in sagittal focusing configu-ration in order to reduce the slope error aberration con-tribution to the degradation of the resolving power. Agas ionization cell provided with a channeltron ismounted downstream the Exit Slit chamber for low en-ergy calibrations. A chamber hosting a second channel-tron and a carousel of solid samples is also installed forhigh energy calibrations. A set of beam attenuators (Alfoils) can also be inserted into the beam path in order toavoid saturation of photon detectors operated in count-ing mode.During the commissioning of the beamline, we obtainedpreviously unachieved energy resolution for all the mea-sured gas absorption lines in the 200-900 eV range. Infact, some of our overall absorption linewidths (N2 , CO1s Æ π*) were even narrower than the natural linewidths

Fig. 1. Layout of the beamline optics. The collimating and focusing pa-raboloidal mirrors (P1 and P2), as well as the refocusing toroidal mirror(RT) are placed in sagittally focusing configuration.

Fig. 2. The vibrational splitting of the N2 1s → p* transition, taken at thesecond diffraction order, with a 50% shadowing of the first mirror. Thetotal linewidth of the first vibrational peak is 123 meV. At that time, a 128meV width was reported in the literature as the natural linewidth value.Our experimental data have been fitted to five Voigt functions plus threeLorentzian curves for the fainter peaks. A natural linewidth Γ = 116 ± 2meV has been obtained.


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reported in the literature. Very accurate fitting proce-dures, allowed us to determine new realistic naturallinewidths with high accuracy for the reference gases (Ar,N2, CO, Ne), which have been later confirmed by theGAPH beamline at Elettra. Data for N2 are shown in Fig.2. The corresponding resolving power reaches 10000 at400-500 eV, while decreasing to 7500 and 5000 at 250 and900 eV, respectively. This high resolving power is ob-tained with a high photon flux (in the range of 1010 ph/s).A 3000 resolving power is given in the whole 200-900 eVrange with a photon flux always higher than 1011 ph/s. Further details can be found on Ref. [2].

ALOISA Experimental stationAs shown in Fig. 3, the end station of the ALOISA beam-line is formed by a preparation chamber and a rotatableexperimental chamber that are coupled via a system oftwo differentially pumped stages and ball bearings. Themanipulator, carrying the sample holder, is horizontallymounted and the X-ray beam passes through its head,along its main axis. Inside the experimental chamber,there are two rotating frames which host the detectors.

The differential pumping stages of the two frames areconnected to those of the exp./prep. chamber. Ultra-High-Vacuum conditions in the 10-11 mbar range is rou-tinely achieved in the experimental chamber. The experi-mental chamber and its detector frames can be rotatedwithout affecting the vacuum at the 10-12 mbar level.The experimental chamber is equipped with several de-tection systems (Fig. 4):- 7 hemispherical electron analyzers[3] are mounted on

two rotating frames inside the UHV chamber. They arededicated to photoelectron diffraction, angle resolvedphotoemission and coincidence spectroscopy.

- 2 photon detectors (energy resolved Si PhotoDiodes) aremounted on the Bimodal frame for surface diffraction.

- 1 phosphorum plate coupled with a CCD detector ismounted at the end of the experimental chamber tomonitor the specular reflectivity.

- 1 channeltron for total yield absorption spectroscopy ishosted on the Bimodal frame.

- A few photodiodes, working in current acquisition,mode are also mounted within the experimental cham-ber for reflectivity monitoring and sample alignement.

Fig. 3. The photon beam enters the ALOISA end station from the preparation chamber through the head of the manipulator (yellow) and reaches thesample surface (red). The phosporum plate (yellow) and five electron analyzers (green) are mounted on the Axial frame (brown). Two electron analyzers(green), two photodiodes and one channeltron are hosted on the Bimodal frame (magenta). One photodiode (light blue) is used to monitor the specularreflectivity while the sample is in the preparation chamber, where an MBE flange (dark blue) hosts several evaporation cells.

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The manipulator is coaxial to the X-ray beam. In thisway the rotations of the manipulator allow one to freelyorient the surface plane with respect to the beam polar-ization (rotation around the beam axis by ± 180°). An az-imuthal rotation of ± 90° is available, independentlyfrom the surface tilt rotation ± 5° which is used for thechoice of the grazing angle on the surface. Liquid Nitro-gen cooling of the sample is available as well as a fast in-sertion system of the sample holder without breakingthe UHV conditions.The experimental chamber rotates around the beam Xaxis and the two frames follow its rotation. The axialframe rotates around the beam X axis too. When the axi-al frame rotates its central analyzer always lies in the ZYplane while the other analyzers are placed at ± 18° and ±36° from the ZY plane.The bimodal frame rotates around an axis perpendicularto the beam X axis, thus the orientation of its rotation ax-is (always lying in the ZY plane) also rotates with thewhole experimental chamber (see Fig. 5). The Bimodalframe hosts two electron analyzers, which point to thecentre of the experimental chamber and are placed 18°one from the other. The two photon detectors are placedat the two external sides of the analyzers, ± 18° furtheraway. The rotating frames, together with the rotating ex-perimental chamber, allow the detectors to explore awide solid angle above the surface for any orientationwith respect to the beam polarization.

HASPES branch line (He Atom Scatteringand PhotoEmission Spectroscopy)In 1998, the INFM Synchrotron Light committee hasfunded the development of a branch line on the ALOISAbeamline. The aim of the branch line is to exploit the lowenergy section of the ALOISA monochromator for allow-

ing external users to attach their own experimental cham-bers; in addition, major overhauling of the ALOISAchamber will be possible while operating the branch line.The branch line is composed by two elements: a new fo-cusing mirror, placed after the ALOISA focusing mirrorand a new Exit Slit (ES) chamber, placed 14 m down-stream the new mirror. This large focussing distance hasbeen chosen to obtain a low angular divergence (< 0.3mrad). In this way no refocusing mirror is required ,making easier the coupling of the ES to any experimen-tal apparatus and increasing the total transmission of thebranch line. An effective energy range of 150-1200 eV ispredicted with the same resolving power and flux of theALOISA beamline. The beam size at the ES will be of 70µm, vertical, and 350 µm, horizontal. The branch linecomponents have been delivered at the end of year 2000,and mounted in year 2001. It is expected to be open toexternal users from 2003.The Surface Structure Division is also modifying its Heli-um Atom Scattering (HAS) apparatus in order to use itas end station of the branch line. At the same time, a newhemispherical electron analyzer (150 mm mean radius)has been developed for the HAS apparatus to match thecharacteristic of the photon beam (both dimension andenergy resolution) at the branch line. The analyzer hasbeen realized and tested by the Instrumentation Devel-opment Group of the INFM in Rome. An energy resolu-tion of 17 meV has been achieved on Auger spectra fromAr. In the year 2002 the new analyzer will be installed onthe HAS apparatus. In addition a new support table hasbeen realized to allow the fine movements for aligningthe HAS apparatus along the X-ray beam of the branchline. This project, running within a university collabora-tion, will allow us to perform in situ both He scatteringand photoemission experiments.

Fig. 4. Inside view of the experimental chamber, showing the electronand photon detectors

Fig. 5. The surface sample (yellow) in Transverse Magnetic polarizationis depicted together with the electron analyzers of the Bimodal (green)and Axial frame (red). The rotation axis for the frames and the experi-mental chamber are also shown.


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Summary of a selection of experimental results.In the past three years of user dedicated operation,ALOISA has been successfully used to performed a fewdozens of experiments. A large part of these experimentshas been carried out in close collaboration between theALOISA GdR and the users, thus involving the GdR inthe data collection, analysis, modelling and final publi-cation of the experiments. Among many systems, theGdR research mainly focused on metal oxides, magneticmultilayers on metals, metal-semiconductor ultrathinfilms.The novel optical design of the monochromator has beenproven to be very effective. Not only it allows a fast in-terchange of the two optical devices for the high and lowenergy range but it has also been proven to reach veryhigh resolution in the low energy range (see Fig.2) main-taining a high photon flux on the sample. A very similaroptical design has been recently chosen for some highresolution beamlines of BESSY II.The combination of a multiplicity of structural and spec-troscopic techniques has been shown to be very usefulfor the study of in situ deposited layers. In particular thecombination of GXRD and PED allows a very accuratedetermination of the structure of films which undergothickness dependent structural transitions. The availabil-ity of X-ray reflectivity during deposition allows a veryprecise measure of the amount of deposited material andtherefore a reproducibility of a particular film thickness.The flexibility of the geometrical arrangement of theALOISA detection system has allowed to exploit new ca-pabilities of Photoelectron Diffraction experiments forthe surface structure determination. A holographic re-construction of the real space around the emitting atomhas been obtained by keeping the electron analyser nearthe nodal plane of the final state wave function. More-over a very accurate determination of surface relaxationhas been achieved by measuring PED patterns in differ-ent geometrical configurations even on systems whereno surface core level shifts is observed to discriminatethe emission from surface atoms.The extent of the angular correlation between the pho-toemitted electrons and the corresponding Auger elec-trons has been measured by angular resolved APECS.Energy resolved APECS combined with resonant pho-toemission has been used to study the Auger lineshaperespectively off and on resonance, in order to correctlyassign different features in the Auger spectra.

Variable polarization PED and Near Node PhotoelectronHolography (NNPEH)A number of experiments took advantage from theunique capability of the ALOISA station to freely selectthe photoemission direction for any orientation of thesurface with respect to the beam polarization vector. The

sensitivity of PED to the surface structure can be en-hanced by comparing emission patterns collected in dif-ferent polarization conditions, while holographic recon-struction have proven to reach atomic resolution if theappropriate surface-polarization orientation is chosen.Recently, PED has been proven to allow the measure-ment of the surface relaxation by taking photoelectronpatterns in systems with a detectable surface core-levelshift[4]. The ALOISA experimental set-up offers an alter-native route to achieve this goal. By exploiting the lightpolarization in the photoelectron diffraction experimentsit is possible to selectively enhance the contrast betweenthe features originated by the lateral vs vertical structure[5]. At medium/high kinetic energy the PED patternsare known to be dominated by the forward scattering(FS) of the photoelectrons along the direction of closepacked rows of the atoms.When applied to the s-symmetric atomic core levels, thisnovel measurement method yields information about theinterlayer separation if the surface is illuminated by lightpolarized in Transverse Electric (TE) mode. In fact the FSoccurs at grazing emission and higher-order vertical-spacing sensitive diffraction peaks, can be more easilyevaluated. The reverse occurs in Transverse Magnetic(TM) polarization, where the FS occurs mainly along thesurface normal and the sensitivity to the intralayer atom-ic distance is enhanced. As shown in Fig. 6 for theZnO(0001) surface case, the method consists in the mea-surement of full 2π patterns in both TE and TM polariza-tion, and in comparison to the model calculated patterns.

Fig. 6. Schematics of the TE and TM geometrical set-up for the variablePED experiments. The measured 2p patterns of Oxygen 1s photoelec-trons (K.E. 309 eV) from the ZnO(0001) surface.

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The variable polarization PED method has been success-fully applied to the study of TiO2 (110) surface relaxation(O 1s level and photoelectron kinetic energy ~305 eV),for which theoretical predictions and experimental re-sults are in good agreement. The analysis carried out onthe ratio of the TE and TM patterns clearly shows thesensitivity to the surface relaxation of this technique tobe at least comparable with the one of SXRD on the samesystem. Results are summarized in Table 1, where a1 anda2 are structural parameters relevant to the O atoms re-laxation on the topmost layer .

a1(Å) a2(Å)

SXRD [6] 0.86 ± 0.13 0.8- 0.9

Ion Scattering [7] 0.8 - 0.9 -

Theoretical prediction [8] 1.05 0.00

Variable polarization PED [9] 0.87 ± 0.04 0.05 ± 0.03

Table 1. Comparison among the values of the structural parameters relat-ed to the position of Oxygen atoms in TiO2(110). Further details on theexperiments can be found in Ref.[9].

In the last decade, metal oxide surfaces have become theobject of a widespread attention within the surface sci-ence community. The goal of these investigations is todepict a consistent structure-reactivity relationship formetal oxides, a class of materials which plays a relevantrole in many catalytic processes. Among the oxides, thewurtzite-type ZnO is one of the most studied systemsand several investigations have been carried out on the(10 -10) and the polar (0001) and (000 -1) surfaces. As faras the (0001) surface relaxation is concerned, literaturedata give contrasting evidences: from 0.2-0.3 Å inwardrelaxation of the topmost Zn layer, to ~0.3 - 0.4 Å out-ward relaxation (from coaxial impact-collision ion scat-tering data).

The variable polarization PED method has been appliedto the determination of Zn0 (0001) surface relaxation, forwhich a general agreement among the experimental dataand theoretical predictions is missing. O1s and Zn 3s 2ppatterns in both TE and TM geometry have been collectedat an outgoing photoelectron kinetic energy of ~310 eVThe O1s χTE/TM modulation pattern has been analysed bymeans of theoretical multiple scattering (MS) simula-tions. Data and results are summarized in Fig. 7.The interlayer distance between the topmost Zn atomsand the underlying O atoms (a) has been varied and thebest agreement with the experimental data has beenfound for a slight inward relaxation of the topmost Znlayer by 0.044 Å. The analysis of the Zn 3s χTE/TM is inprogress. The possibility to obtain holographic reconstructionstarting from the photoelectron diffraction patternwould be of great help in determining novel/unknownsurface structures. The holographic reconstruction is dis-turbed by the presence of strong forward scattering (FS)effects in the photoelectron diffraction pattern [10]. FS,being 0th-order diffraction peak, produces spurious fea-tures in the real space image and substantially masks theatomic positions. A novel experimental procedure hasbeen suggested[11] and successfully applied at theALOISA beamline[12,13,14]. It makes use of the linearpolarization of the synchrotron light and of the photoe-mission dipole selection rules to strongly reduce the for-ward scattering component in the photoelectron diffrac-tion pattern. In fact, by measuring the 2s level emissionon Al(111) and keeping the electron detector almost per-pendicular to the polarisation direction (“Near Node”geometry) we have shown that the holographic recon-struction is feasible, clearly yielding atomic resolutionand the correct nearest neighbours distances. The resultsare shown in Fig. 8 and 9.

Fig. 7. Left panel : modulation pattern c TE/TM from oxygen 1s (K.E. = 309 eV) level from the ZnO(0001) surface. Central panel : the reliability factoranaylsis resulting from the comparison with the MS model calculations as a function of topmost Zn-O interlayer distance. Right panel: side view alongthe <1-100> direction.


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Magnetic Linear Dichroism in the Angulr Distributionof Photoelectrons (MLDAD)The atomic-like behavior of the photoionization crosssection of core levels in solids is remarkably displayed inthe observation of linear magnetic dichroism in the an-gular distribution (MLDAD) of photoelectrons. Struc-ture-related effects are clearly visible as modulations ofthe dichroism signal, induced by Photoelectron Diffrac-tion, a fact that can be exploited to obtain informationfrom magnetic surfaces[15,16,17]. The experimental set-up is sketched in Fig. 10. The chirality of the experimentis determined by the mutual orientation of the photo-electron wavevector k, the sample magnetization M andthe beam electric field E. In order to highlight modula-tions related to the crystal structure of the sample, thepolar emission angle is scanned by rotating the samplenormal around the beam axis, i.e. with fixed chirality.We performed measurements on the 3p line in

Fe(001)[18, 19, 20], with the aim of verifying the possibil-ity of exploiting PED effects in the dichroism signal todisentangle surface and bulk magnetism.In order to separate experimentally the surface and bulkcontributions, ultrathin Co/Fe pseudomorphic overlay-ers were also grown on the Fe(001) surface. The Fe bulkbehaviour was isolated by growing a thin (~3Å) Cooverlayer on the clean Fe, creating a system similar to aCo surface on top of a Fe bulk. Then, the chemical identi-ty of bulk and surface atoms was reversed by growing athicker (9Å) Co layer and a Fe surface layer on top. Re-sults are shown in Fig. 11: of MLDAD modulations areseen to be peculiar of the bulk signal, a fact which con-firms their PED nature and can be used as an estimate ofthe bulk sensitivity of the experiment.

Structure and morphology of ultrathin metallic layersFe films on Cu3Au(001)The evaporation of Fe on suitable substrates has beendemonstrated to be a valid route to the formation of Fefilms with different magnetic properties with respect tothe bulk (e.g. antiferromagnetic or superferromagnetic),thanks to the possibility of distorting the Fe lattice cellfrom its bcc natural form[21,22,23]. Cu3Au(001) is veryattracting substrate since it allows one to grow Fe filmswith different kind of phase structure depending on thesubstrate temperature, film thickness, surface prepara-tion[24]. We have investigated the Fe/Cu3Au(001) sys-tem in a thickness range from 1 to 20 ML by a combinedX-ray and photoelectron experiment at the ALOISAbeamline[25,26]. In-plane XRD was used to determinethe lateral lattice spacing of the growing film, while for-ward scattering PED polar scans along the main symme-try directions gave us the complementary angular infor-

Fig. 8. Stereographically projected experimental Al 2s (K.E. 952 eV) pho-toelectron diffraction patterns from Al(111) single crystal. Comparisonbetween “Far node” (a,d) and “Near Node” (c,f) photoelectron data andtheir holographic real space reconstructions for the z=0 plane containingthe emitter.

Fig. 9. The holographic 3D image as obtained from the PED data. Theatomic environment of the Al 2s emitter at (0,0,0) is shown inside a shellof 4Å radius.

Fig. 10. Geometry for MLDAD experiments. The sample magnetizationM is imposed parallel to the beam direction. The polar emission angle βis scanned by rotating the surface normal n around the beam axis.

10



mation to extract the vertical lattice structure (Fig. 12).We have seen that Fe initially grows with an fcc struc-ture pseudomorphic to the substrate. Au surface segre-gation has been also observed to affect the pseudomor-phic phase in this thickness range. At ~10 Å, a newstructural phase is observed on top of the pseudomor-phic one (at this thickness a spin reorientation transition

was also reported to take place). Finally, at about 15 Å, athird phase nucleates on top of the growing film, with adistorted bcc structure. As the thickness is further in-creased, the latter phase gradually approaches the Fe bccbulk structure.

The Sn-Ge bonds in the (3x3)->( √3x√3)R30° phase tran-sition of Sn/Ge(111)Following the debate about the nature of the (3x3) ->(√3x√3)R30° phase transition of 1/3 ML of Sn onGe(111)[27,28], several studies focused on the structuredetermination of the two phases[29, 30]. In fact, a changeof the atomic structure would have favoured a chargedensity wave driven transition against an order-disorderone, the former model would have implied a metal tosemiconductor transition as well, and even low tempera-ture ferromagnetism. Previous XRD and LEED experi-ments gave contradictory results, while photoemissionexperiments suggested the structure to remain unalteredthroughout the transition. In fact, two components areobserved in the Sn 4d photoemission spectrum whichimply the presence of two types of inequivalent Snatoms in the (3x3) unit cell. This spectrum does notchange in the room temperature phase. We studied theSn/Ge(111) structure by means of energy dependentPED from the Sn 4d spectra[31]. In particular, we ex-ploited the variable scattering geometry offered byALOISA, to independently measure the bond length be-tween Sn and its nearest neighbour Genn atoms and theSn vertical height above its next nearest neighbor Gennn

atom. This is achieved by orienting either the bond di-rection either the surface normal along the polarizationvector and placing the electron analyzer in the corre-sponding direction (as depicted in Fig. 13).We found that the two kind of Sn atoms only differs bytheir vertical height, while the Sn- Genn bond length is

Fig. 11. Angular dependence of the amplitude of the dichroic differencespectra in the different Fe/Co systems. The shadowed areas representthe maximum error in the determination of the magnetic signal, i.e. theamplitude (maximum - minimum) of the normalized difference spec-trum. In the inset, normal vs off-normal spectra, for the Co/Fe(001) case.

Fig. 12. Left panel: Fe Auger LMM angular scans along <100> for differ-ent Fe coverages on Cu3Au(001) surface. Right panel : (H,0,0) radialscans taken on Fe films of different Fe thicknesses. The pattern from theclean substrate is also reported (yellow markers). The appearance of theα’ and α peaks witnesses the gradual evolution of the Fe film from apseudomorphic phase to an orthomorphic one. At about 20 Å, the threephases are seen to coexist.

Fig. 13. Geometry used for the determination of the Sn-Ge bond length.A typical photoemission spectrum is shown in the inset, showing contri-butions from Sn atoms located in different environments.


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the same (i.e. the three Genn atoms follow the Sn verticaldistortion). The vertical ripple we found (0.3 Å) is ingood agreement with both XRD studies and ab initio cal-culations. In addition, the same structure is also pre-served in the room temperature phase.As a consequence, the transition must be of the order-disorder type, in full agreement with our findings of a 3-state Potts transition obtained by He Atom Scatteringstudy of the (3x3) long range order parameter[32].

Thin Pb films growth on Ge(001)The electronic properties of a thin metal film deviatefrom the corresponding bulk ones when the film thick-ness D is comparable with the wavelength of the elec-trons at the Fermi level [33, 34]. This phenomenon, alsoknown as Quantum Size Effect (QSE), is expected to beat maximum when D is an odd multiple of λF /4, where-as it disappears for D=nλF /2 [35]. Structural variationdue to QSE is also expected [36, 37]. We first observed byHAS a structural modification due to QSE during layer-by-layer growth of Pb(111) on Ge(001) at 130 K[38]. Themeasured monoatomic step height was varying as muchas 15% around the Pb bulk interlayer separation. TheQSE fingerprint is witnessed by the oscillatory variationof the step height. Since HAS is sensitive to the valenceelectron density of the topmost layer, no direct informa-tion on the rearrangement of the interlayer distances in-side the Pb film was available. Moreover the mechanismof the layer by layer growth at low temperatures is stillunclear. In order to gain complementary insight into thePb growth at low temperature, we have performed XRRand XRD measurements at the ALOISA beamline. Moni-toring the X-ray specular reflectivity during Pb deposi-tion, information about the flatness of the deposited filmhas been obtained and also the deposition rate has beencontrolled accurately. The growth oscillations have beenmeasured for a few photon energies and a layer by layergrowth regime was observed to set in for coverageshigher than 5 ML with extremely low film roughness(see Fig. 14).For earlier deposition stages the morphology seems to besubstantially rough, indicating that between 4-5 ML atransformation in the growth mode takes place. The verti-cal structure of the film has been explored by scanning thePb(111) diffraction peak for different vertical momentumtransfer (rod scan).We found that Pb atoms aggregates in-to the crystal structure with at least 3 layer thickness. Sim-ulation of the measured rod scans (Fig.15) indicates thatthe step height oscillates as shown by HAS measurementsbut the oscillations are less pronounced amounting to amaximum of 6-7%. This result implies that the valenceband electron density oscillates more than the nuclear po-sitions, as could be expected for a quantum size effect,which mainly involves the Fermi level electrons.

Fig. 14. X ray specular reflectivity growth oscillations during Pb deposi-tion on Ge(001) at 140 K. The vertical line marks the transition to the lay-er by layer growth regime. The oscillation period for different photon en-ergies is also shown.

Fig. 15. Rod scans of the (2,-2,0) reflection from Pb(111). Each data pointrepresent the integrated intensity of an azimuthal scan of the diffractedpeak for the given vertical momentum transfer L (in Pb(111) reciprocallattice units). The first two deposition stages correspond to the 3Dgrowth regime. For the ticker layers layer by layer growth has already setin. Both morphology and vertical structure rearrange at the critical thick-ness of 5 ML.

AR-APECS measurements In APECS (Auger Photoelectron Coincidence Spec-troscopy) the energy distribution of Auger electron ismeasured in time coincidence with its associated photo-electron or vice versa. This ensures that both electronsare generated in the same photoexcitation event. In thisway an unprecedented discrimination is achieved, suchas the capability to isolate individual sites, separateoverlapping structures, eliminate uncorrelated sec-ondary electron background, eliminate core hole lifetimebroadening [39].As in conventional spectroscopies, such as AES and XPS,the amount of information is vastly increased whenmeasuring the angular distribution (as in Auger andphotoelectron diffraction for instance) in a similar wayangular resolved APECS (i.e. AR-APECS) is expected toadd an important new level of discrimination.In one of most recent experiments we have measured theangular distribution of Ge L3M45M45 Auger electrons incoincidence with Ge 2p3/2 core photoelectrons along the

(001) direction of the Ge(100) surface [40]. As shown inFig.16, intensity modulations arising from diffraction ef-fects are suppressed in the coincidence Auger angulardistribution and, when specific emission angles of thephotoelectrons are considered, new features appear. Weattribute the former effect to enhanced surface specificityof the coincidence technique and the latter to sensitivityof the coincidence measurement to alignment of the corehole state. This last effects reflects in the possibility todiscriminate angular and magnetic sublevel in both theAuger and phoelectron source wavfunctions and to mea-sure their energy and/or angular distribution. Finally,by also noting that AR-APECS, by detecting the coinci-dent photoelectron, preserves the chirality of the ionisa-tion event and then opens the possibility to measuredichroic effects in the Auger emission, this new applica-tion of the coincidence technique can provide new in-sight in the study of magnetic systems.

ConclusionWe presented an overview of the different experimentaltechniques available at the INFM-ALOISA beamline atELETTRA. They give access to a large number of physi-cal properties of ultrathin films and surfaces, such asstructural and morphological evolution during growth,electronic structure, surface and subsurface magnetism,phase transitions, reduced dimensionality structural ef-fects. In particular, the benefits related to the possibilityof combining different techniques on the same apparatushave been highlighted. We have shown a selection of re-cent results for several systems, as well as the main fea-tures of the beamline and of the experimental station.

References1. Details of the experimental chamber can be found at the web

page www.tasc.infm.it/tasc/lds/aloisa/aloisa.html.2. L. Floreano, G. Naletto, D. Cvetko, R. Gotter, M. Malvezzi, L.

Marassi, A. Morgante, A. Santaniello, A. Verdini, F. Tom-masini and G. Tondello, Rev. Sci. Instrum. 70 (1999) 3855.

3. R. Gotter, A. Ruocco, A. Morgante, D. Cvetko, L. Floreano, F.Tommasini, and G. Stefani, Nucl. Instrum. Methods A 467-468 (2001) 1468.

4. E.D.Tober, R.X.Ynzunza, F.J.Palomares, Z.Wang, Z.Hussain,M.A.Van Hove and C.S.Fadley, Phys. Rev. Lett. 79, 2085(1997)

5. M. Sambi and G. Granozzi, Surf. Sci. 415, 1007-1015 (1998)6. G.Charlton, P.B.Howes, C.L.Nicklin, P.Steadman, J.S.G.Tay-

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Rev. B49, 16721 (1994)

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Fig. 16. Pair-wise AR-APECS angular distributions of Ge L3M45M45 Augerelectrons measured in coincidence with Ge 2p3/2 core photoelectrons de-tected in each of the five axial electron energy analyzers. The AED andthe coincidence data associated with axial analyzer number 5 are refer-enced to zero, while the other curves are shifted upward for clarity ofpresentation

9. A. Verdini, M. Sambi, F. Bruno, D. Cvetko, M. Della Negra,R. Gotter, L. Floreano, A. Morgante, G.A. Rizzi, G. Granozzi,Surf. Rev. Lett. 6 (1999) 1201.

10. C. S. Fadley, Surf. Sci. Rep. 19, 231 (1993).11. T. Greber and J. Osterwalder, Chem. Phys. Lett. 256, 653

(1996).12. J. Wider, F.Baumberger, M.Sambi, R.Gotter, A.Verdini,

F.Bruno, D.Cvetko, A.Morgante, T.Greber and J.Osterwalder,Phys. Rev. Lett. 86 (2001) 2337.

13. T. Greber, J. Wider, A. Verdini, A. Morgante, and J. Oster-walder, Europhysics news, Sep./Oct. 2001, p. 172.

14. J. Spence, News & Views Nature 410 (2001) 1037.15. F. U. Hillebrecht, H. B. Rose, T. Kinoshita, Y. U. Idzerda, G.

van der Laan, R. Denecke, and L. Ley, Phys. Rev. Lett. 75,2883 (1995).

16 R.Schellenberg, E.Kisker, A.Fanelsa, F.U.Hillebrecht,J.G.Menchero, A.P.Kaduwela, C.S.Fadley, M.A. Van Hove,Phys. Rev. B57 14310 (1998) .

17. G.Panaccione, F.Sirotti, G.Rossi, Solid State Comm. 113(2000) 373

18. F. Bruno, D. Cvetko, L. Floreano, R. Gotter, A. Morgante, A.Verdini, G. Panaccione, M. Sacchi, P. Torelli, and G. Rossi, J.Magn. Magn. Mater. 233 (2001) 123.

19. F. Bruno, R. Gotter, A.Morgante, A. Verdini, G. Panaccione,M. Sacchi, F. Sirotti, P. Torelli, Physica B, in press.

20. F. Bruno, G. Panaccione, A. Verdini, R. Gotter, L. Floreano, P.Torelli, M. Sacchi, F. Sirotti, A. Morgante and G. Rossi, ac-cepted for publication on Phys. Rev. B.

21. M. Wuttig, B. Feldmann and T. Flores, Surf. Sci. 331-333, 659(1995).

22. G.C. Gazzadi, F. Bruno, R. Capelli, L. Pasquali, S. Nan-narone, Phys. Rev. B 65 (2002) 205417.

23. S. Tacchi, F. Bruno, G. Carlotti, D. Cvetko, L. Floreano, G.Gubbiotti, M. Madami, A. Morgante, and A. Verdini, Surf.Sci., in press.

24. P.M. Marcus and F. Jona, Surf. Rev. and Lett. 1, 15 (1994).25. F. Bruno, D. Cvetko, L. Floreano, R. Gotter, C. Mannori, L.

Mattera, R. Moroni, S. Prandi, S. Terreni, A. Verdini and M.Canepa, Appl. Surf. Sci. 162-163 (2000) 340.

26. F. Bruno, S. Terreni, L. Floreano, A. Cossaro, D. Cvetko, P.Luches, L. Mattera, A. Morgante, R. Moroni, M. Repetto, A.Verdini, and M. Canepa, Phys. Rev. B, in press, cond-mat/0103458.

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31. L. Petaccia, L. Floreano, A. Goldoni, D. Cvetko, A. Morgante,L. Grill, A. Verdini, G. Comelli, G. Paolucci and S. Modesti,Rev. B 64 (2001) 193410, cond-mat/0103358.

32. L. Floreano, D. Cvetko, G. Bavdek, M. Benes, and A. Mor-gante, Phys. Rev. B 64 (2001) 075405

33. R.C.Jaklevic, J.Lambe, M.Mikkor and W.C.Vassell, Phys. Rev.Lett. 26, 89 (1971)

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35. F.K.Shulte, Surf. Sci. 55, 427 (1976)36. P.J.Feibelman, Phys. Rev. B 27, 1991 (1983)37. S.Ciraci and I.P.Batra, Phys. Rev. B 33, 4294 (1986)38. A. Crottini, D. Cvetko, L. Floreano, R. Gotter, A. Morgante

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and R.A. Bartynski, submitted.


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SIMULATION OF THE UPGRADE OF THEBACKSCATTERING SPECTROMETER IN13 AT ILL

C. Mondellia, M. Béeb, A. Deriuc and F. Natalia

(a) Istituto Nazionale per la Fisica della Materia, OGG, CRGIN13 Institut Laue Langevin B.P. 156, F-38042 GrenobleCedex 9

(b)Université Joseph Fourier, Domaine Universitaire, B.P. 82Saint Martin D'Héres-Giéres 38042 Grenoble Cedex, France(c)Universitá degli Studi di Parma, Parco area delle Scienze7/A, I-43100 Parma,Italy

Articolo ricevuto in redazione nel mese di Novembre 2001

AbstractRay tracing becomes more and more a very helpful toolin the project of new instruments as well as in the up-grade of existing instruments.The availability of different packages and codes and oflarge libraries has contributed to the generalized use ofMonte Carlo simulations in the frame of instrument pro-jects. In the specific case of IN13 a progressive upgrade of theinstrument is planned in order to improve the incidentflux - as in the present configuration the performance ofthe instrument is overall limited by the low incident flux- and also to increase the instrument versatility. In thisway, different possibilities other than the present stan-dard configuration will be available in order to allow theuser to define the best compromise between flux, energyresolution and Q-range for each experiment. The first step of this project consists of simulating the in-strument and the different modifications envisaged inorder to verify our ideas and to determine which are themost promising modifications and the possible degrada-tion of certain characteristics of the instrument. This aparticularly important point, as one has to preserve thecharacteristics that make of IN13 a particularly suitedspectrometer for the study of the local dynamics of softmatter, such as polymers and biological systems, e.g. alarge momentum transfer range (now 0.3<Q(Å-1)<5.5)and an energy resolution of few µeV. Thus we have performed Monte Carlo simulations of theprimary spectrometer and our results together with datafrom experimental tests show that IN13 could be modi-fied in order to obtain a gain in neutron flux up to a fac-tor of 12.

Introduction In the eighties the study of tunneling effects was verypopular and the back-scattering (BS) spectrometer IN13at the Institut Laue Langevin (ILL) was specially de-signed for this kind of experiments [1]. Thus, it wasbuilt in order to achieve a good energy resolution with alarge Q-range, being these the more important character-istics for such experiments. The drawback is that thiscould be obtained only at the expense of intensity. This isnot a severe limitation in the study of the tunneling, as

one needs to determine only the position of inelastic tun-neling peaks and not the peak shape and measurementsat large Q are not limited by the Debye-Waller factor be-cause they are generally carried out at low temperaturesand using single crystals, so reducing the problem repre-sented by the Bragg scattering from the sample.However, since 1998 the instrument is dedicated mainlyto the study of the dynamics of biological systems, agrowing field in physics. In this frame the neutron flux iscritical as the samples are typically small and the analy-sis of the shape of the quasi-elastic signal is very impor-tant. Additionally, the lack of single crystals makes rele-vant the problem represented by Bragg reflections andmost of the experiments are performed close to roomtemperature so posing also the problem of the attenua-tion at large Q due to the Debye-Waller factor.In this new context, a project of renovation and redesignof the instrument was started together with the discus-sions at ILL for renovating the H24 guide, where IN13 islocated, using supermirrors. The basic idea of this upgrade is to give the instrument aflexible character, by allowing reversible modificationsto be easily carried out in order to adapt it to the opti-mum compromise between all the relevant experimentalparameters, namely flux, energy resolution, Q-range andQ-resolution [2].The simulation of the instrument is particularly impor-tant to study the effects of the different envisaged trans-formations on both flux and energy resolution at thesample, and analyze the consequences of any futuremodification. A particular effort is needed to improvethe flux on the sample, but unfortunately, it is no possi-ble to increase the flux without loosing energy or Q-reso-lution. However the users of IN13 typically need differ-ent characteristics because they have very different inter-ests; so often one or more of these parameters can be re-laxed to increase the neutron flux. Thus, a first proposi-tion to increase the neutron flux was to set the analyzerplates out of the exact BS geometry by moving the detec-tor into a position where it could not receive the neu-trons directly scattered by the sample. In that case theresolution is worsened, as one deviates from exact BSgeometry, but the chopper – which is used to allow toseparate the direct scattering from the neutrons that

come from the analyzers and has a duty cycle of 33% – isnot needed anymore, so the numbers of neutrons reach-ing the sample can be increased by a factor of 3. Simula-tions confirmed by experimental tests have shown thatthis is feasible: We find that moving the analyzers 1 de-gree out of the BS-geometry changes the energy resolu-tion from 8 µeV to 15 µeV (FWHM), which can be still anacceptable resolution in many cases. Unfortunately, larg-er deviations from perfect BS give rise to an unaccept-ably large resolution function, so the geometrical con-

straints make possible this out of BS option only for thestudy of small samples. However, this is the case inmany biological experiments, so this could be still a veryhelpful possibility.Apart from the energy resolution, another problemposed by the stopping of the chopper is the presence ofother harmonics in the neutron beam: λ/2, λ/3, ... whichare normally eliminated by a suitable choice of the chop-per’s duty cycle. Luckily this does not seem to be a seri-ous problem as the relative amount of l/2 measured inthe incident beam is only of the order of 10% and this ra-tio is certainly smaller for the neutrons impinging on thedetectors because of the selective reflectivity of the ana-lyzers. One of the most important and distinctive feature ofIN13 is its large Q-range (0.3<Q(Å-1)<5.5).The instrument is equipped with seven analyzer platesand three small angle circular analyzers (at the momentnot used in perfect BS geometry) covering the scatteringangle range 5.8 < 2Θ< 156º. The instrumental configuration is fixed and a large partof the high Q analyzers is shielded with cadmium toavoid the Bragg peaks arising from the aluminum wallsof the cryostat. This results in a lose of flux of about 20%,a loss which increases when the sample itself scatters co-herently as further angles then have to be covered. Addi-tionally, for liquid and disordered systems close to roomtemperature there is a strong decrease in the scattered in-tensity at large Q values because of the Debye-Waller at-tenuation, so in many cases the larger angles are notused at all. Thus, we are studying a modification of theinstrument that would allow moving some of the ana-lyzers to the side of negative scattering angles.In this way the corresponding scattering angles wouldbe measured with both ±2Θ analyzers, and there wouldbe an increase in intensity by a factor 2 for the corre-sponding momentum transfers.In order to achieve this goal several modifications of thespectrometer are required:At present there is a single bank of 32 detectors and theset of analyzers at small angles is fixed, thus preventingthe rotation of the analyzers plates on the side of thecarousel [3] (see Fig. 1a). We will have to rebuild thebank of detectors (dividing it in 7 independent blocs)and to modify the carousel and the system of fixation ofthe small angle analyzers in order to permit the rotationof the analyzer plates along the carousel to the chosenposition (see Fig. 1b). This version of the instrumentwould allow three different setups - shown in Fig. 2 - andthe possibility to record twice the same signal either atsmall or large scattering angles or maintaining the sameangular as now (each angle being measured only once).Another improvement under study is the replacement ofthe neutron guide H24. The present guide is coated with

Fig. 1. Possible set ups of IN13 moving two of the analyzer plates on thenegative scattering angles. a) Image of the present configuration of IN13;b) New set up of the analyzers and detectors allowing to install some ofthe analyzers plates on the side of the negative scattering angles to ob-tain a gain of the flux of a factor 2 for the corresponding Q values.


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nickel and its reflectivity has decreased over its lifetimeso the outcoming flux now is 30% lower than it was 20years ago [4]. Therefore a simple replacement of the Ni-coated guides will provide a subsequent increasing onneutron intensity. Moreover, the possibility of equippingthe guide with supermirrors (SM) and changing its di-mensions is also being considered. The cross section ofthe neutron beam could change from 3x20 cm2 to 4.5x20cm2. This decision concerns the three instruments pre-sent along the guide: IN3, IN13 and D10 and each instru-mental team has to study the conditions under which itcould fully benefit from this operation. For IN13 a partic-ular emphasis has to be put on the size and divergenceof the beam because they can influence noticeably theenergy and Q resolution. Therefore, the effects of thosechanges need to be accurately evaluated by means ofMonte Carlo simulations, as shown in the next section.Further modifications are planned for the upgrade; suchas the substitution of the detector tubes with new tubeswith higher pressure and efficiency, the setting of thesmall angle circular analyzers to perfect BS geometry byusing a new type of concentric detectors, a new cryostat,the addition of new analyzers crystals, etc. However,these points are still under study and they will not bepresented in more detail in this communication.

Results of Monte Carlo simulationsA first step of the upgrade consists in simulating the in-strument in order to determine the effect on both fluxand energy resolution brought by the installation of su-permirrors in the neutron guide. Thus, we have per-formed a series of Monte Carlo simulations of the prima-ry spectrometer using the McStas code [5]. This packagehas been developed to facilitate the simulation of allkind of neutron instruments and it is a very suitable toolto study and project new spectrometers or modify exist-

ing instruments. The general scheme of IN13 is shown inFig. 3. In order to simulate realistically IN13 we use a flatsource with a gaussian divergence mimicking the neu-tron beam that comes from the H24 guide and reachesthe monochromator. This source sends the neutrons to aguide formed by three segments: the first is straight andis L1=3.3 m long; the second one is curved (curvature ra-dius R=27 Km), L2=74.5 m; and the third is straight withL3=6.3 m. Their cross section is constant (3x20 cm2), ex-cept for the last segment, where the height is reduced to12.5 cm because of the presence of the IN3 spectrometeralong the guide. The beam reaches then the monochro-mator, which is a CaF2 crystal (422) formed by three dif-ferent crystals with a mean mosaicity of η= 2.5’. Themonochromatic beam is reflected to the sample positionby a deflector that consists in a pyrolitic graphite (004)crystal (13.4x5 cm2) formed by 9 lamellae η= 45’ (a pic-ture of the present deflector is shown in Fig. 4). Finally, at the sample position we have put several moni-tors with the same dimensions of a typical sample hold-er, i.e. 3x4 cm2, in order to check how the characteristicsof the guide (reflectivity and dimensions) affect the ener-gy resolution and flux. The gain in flux is calculated as the ratio between the in-tensity for a given reflectivity and guide dimensions andthe flux for the present guide, which is simulated takinginto account the lost of reflectivity due to aging. Thus, aNi coated guide with a reflectivity of R0=0.96 instead of 1and width=30 mm was considered. The results are given in Table 1, where one can see thatthe best result obtained without substantial modification

Fig. 2. Sketch of the three different possible choices for the analyzers setup. The new version of the instrument could make possible to recordtwice the same signal either for the small or for the large scattering an-gles as well as to have the same angular coverage as now (full angularcoverage, each angle being measured only once).

Fig. 3. Schematic diagram of the IN13 layout.

of the instrument is reached by using a supermirrorguide (SMG) m=3 with a guide 30 mm wide. On the oth-er side, the replacement of the guide by a wider one isnot so effective as forecasted. In effect, the data given inTable1 show that the increase of the guide cross sectionfrom 4.5x13.5 cm2 to 3.0x13.5 cm2 does not result in a cor-responding increase of the neutron intensity at the sam-ple position, indicating that the extra 50% of neutronsgained by the larger cross section is lost before arrivingto the sample. In order to understand the origin of thisloss we have monitored what happens at the guide exit,the monochromator, the deflector and the sample posi-tion. The results show that all the extra neutrons arriveto the monochromator but afterwards a big percentage islost between the latter and the deflector. This is due tothe fact that the deflector width (5 cm) is not largeenough to recuperate the larger beam coming from themonochromator. In fact the beam width at the deflectoris ~ 5 cm for the 3 cm guide but increases to 8 cm for the4.5 cm guide. This is due to the high beam divergenceproduced by the supermirror guides, as can be seen inFig. 5, where a comparison between the beam size on thedeflector is shown for the cases of 30 mm and 45 mmguides. Besides this, some neutrons are also lost between

the deflector and the sample, as the width of the deflect-ed neutron beam is larger than 3 cm, which is the stan-dard sample size. While this is true in both cases thebeam width is slightly larger for the w=4.5 cm guidethan for the w=3 cm guide, resulting in a bigger loss andproducing the final result that the intensity at the sampleposition is practically the same. We have checked the ef-fect of using a larger deflector (8 cm wide), but althoughthe results are slightly better, a lot of neutrons are stilllost because of the divergence of the beam. Therefore, afirst important result from our simulations is that in or-der to profit from having a wider neutron guide severalchanges should be envisaged. First, the IN13 deflectorshould be reviewed, making it wider (at least 8 cm) andfocusing not only vertically but also horizontally. Otherproject under study is the possibility of redesigning thelast segment of the neutron guide to make it focusing orof adding a focusing guide between the monochromatorand the deflector. Further simulations are currently usedto test all of these ideas.

Fig. 5. Image of the neutron beam after being backscattered on themonochromator. Both pictures have been obtained using a position sensi-tive monitor with the dimensions of the present deflector and situated at90 cm from the monochromator (i.e. 12 cm before the deflector). The topfigure corresponds to the simulation results obtained with the 30 mmguide and the bottom figure to the 45 mm guide.

Fig. 4. Present deflector of IN13. It is composed from nine lamellae of py-rolitic graphite (004) crystal (13.4x5 cm2, η= 45’)


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18



Guide width (mm) Ni 58Ni SMG(m=2) SMG(m=3)

30 1.23 1.31 1.79 1.85

45 1.23 1.34 1.80 1.88

45* 1.34 1.48 2.09 2.19

Table 1 Gain of the flux at the sample position for different guide reflec-tivity. The reported quantity is the ratio between the number of neutronsreaching the sample position for a new ideal guide and the present situa-tion which corresponds to an aged Ni coated guide (see text). The firsttwo rows show the results obtained simulating the present deflector (5cm wide), the latest row marked by a star shows the results obtainedwhen a new deflector 8 cm wide is used in the simulation.

The effects of the change of the guide coating on the en-ergy resolution function were also studied, because it isimportant that the gain of the flux occurs without a toobig detriment of the energy resolution. The FWHM of the energy distributions of the neutronsarriving at the sample does not change significantly (seeFig.6), but their shapes are different. The tails of thecurves are more extended for the case of the SMG, whichcan be a disadvantage for the study of phenomena thatshow very small quasi-elastic broadening. On the otherside it looks acceptable for most of experiments.

ConclusionsThe aim of the upgrade of IN13 is to obtain a very flexi-ble instrument, which can be adapted to each experi-ment in order to obtain the best compromise betweenflux, energy resolution, Q-range and Q-resolution.In order to optimize the choice of the neutron guide andto obtain a reliable estimation of the gain in intensity andthe effect on the energy resolution, Monte Carlo simula-tions of the primary spectrometer were performed. Theresults show that the neutron intensity on the samplecan be multiplied by a factor of ~2 by using a SMG (ei-ther with m=2 or m=3). This could be combined with anew set up of the analyzers that will permit to multiplyit by a factor 2 in a chosen Q-range. Furthermore, whenthe quantity of sample is small it is possible to use a con-figuration of the instrument where the analyzers arealigned slightly out of BS and the chopper can bestopped, which would result in an additional gain by afactor 3. Thus a total gain of about one order of magni-tude can be expected, at least in special cases. Althoughsuch an increase would only be possible for small sam-ples, this is the usual case with biological systems and itis precisely then that the higher flux is more needed.In the future, further simulations including the sec-ondary spectrometer will be performed to determine theconsequences of any other modifications.

AcknowledgmentsParticular thanks go to M. A. González from the ILL forthe help given on the use of the McStas simulation pack-age and useful discussions.

References1. M. Prager and A. Heidemann, ILL Internal report, Grenoble

1995. 2. M.Bée, “Dynamical characteristics of biological systems

from neutron scattering experiments and relation to biologi-cal function.” CRG IN13 Internal report, Grenoble 2001.

3. See the IN13 home page:www.ill.fr/YellowBook/IN134. W. Kaiser, Flux measurements performed on the H24 guide

indicate that the reflectivity has decreased over 30 years ofoperation, resulting in a loss of flux of around 30%. Privatecommunication.

5. K.Lefman and K.Nielsen, Neutron news 10/3, 20 (1999).

Fig. 6. Energy resolution functions for the different guides proposed(30mm wide, 108 events were generated at the neutron source.

Abstract Force and shortening in muscle are thought to be drivenby a conformational change (the working stroke) in themyosin head domains that cross-link the myosin andactin filaments. However definitive evidence linking thestructural changes, seen in isolated myosin head frag-ments by crystallography, to the motor action in the pre-served structure has not yet been produced. The im-proved brightness and collimation of the X-ray beam atbeam line ID2 at the European Synchrotron RadiationFacility (ESRF, Grenoble, France) led to the developmentof a new technique that can measure the axial motions ofmyosin heads in muscle with Å sensitivity. The methoddepends on X-ray interference between the two arrays ofmyosin heads in each bipolar myosin filament, whichsuperimposes a finely spaced fringe pattern onto the~14.5 nm X-ray reflection (M3) originating from the axialrepeat of the myosin heads along the thick filaments [1]. We used this method to study the motions of myosinheads in single intact fibres from frog muscle during thesynchronous execution of the working stroke elicited byrapid decreases in length superimposed on an isometriccontraction [2]. During the isometric contraction the M3reflection is composed of two major peaks with axialspacings 14.46 and 14.67 nm; the ratio of the intensitiesof the high angle peak to the low angle peak, IHA/ILA, isabout 0.8. Shortening steps reduce the value of IHA/ILA toa minimum value of ~0.3, as expected for displacementof the myosin heads towards the centre of the myosin fil-ament. The results indicate that tilting of the lever arm ofthe myosin head is the mechanism that drives force gen-eration and up to 10 nm filament sliding.

Structure of the sarcomere In the striated muscle the contractile proteins, myosinand actin, are organised into filaments that overlap inaxially repeating structural units called sarcomeres (Fig.1A). In each sarcomere the myosin (thick) filament,about 1.6 µm long, is made of two symmetrical halves,each containing about 150 myosin molecules, connectedat the centre of the sarcomere by the M line. The actin

(thin) filament, 1 µm long, originates from the Z linebounding the sarcomeres and partially overlaps with themyosin filament. The myosin molecule is a dimer withan elongated portion, the tail, made by the coiled coil al-fa helices of the two monomers, which lies on the thickfilament, and two large globular portions, the myosinheads, that emerge from the thick filament. To form thethick filament, the tails assemble in an anti-parallel man-ner starting from the M line, so that myosin heads areoriented in opposite directions in the two halves of thefilament and a region of ~ 0.2 µm around the M line isfree of myosin heads (bare zone, Fig. 1B). Crowns ofthree pairs of heads emerge from the thick filamentevery ~14.5 nm (Fig. 1C). Successive crowns are rotatedby 40° forming a three-stranded helix with ~ 43 nm peri-od. Actin monomers (diameter 5.5 nm), with axial peri-odicity of 2.73 nm, are arranged in a double stranded he-lix in the thin filament with pitch 37 nm.Force and shortening in muscle are generated by cyclicinteractions of the myosin heads with the adjacent thinfilaments in the region of overlap. During the interactionthe myosin head undergoes a conformational change(the working stroke) that, depending on the mechanicalconditions, can generate a force of several pN or an axialdisplacement of the actin filament toward the centre ofthe sarcomere of several nm. The work produced is ac-counted for by the free energy of the hydrolysis of ATPon the catalytic site of the myosin head.

A crystallographic model of the working strokein the myosin headBiochemical studies of contractile proteins in solution [3]provided evidence that the energy liberation by the acto-myosin complex is mainly associated with the release ofthe ATP hydrolysis products, phosphate and ADP. In theabsence of ATP, the nucleotide-free myosin head strong-ly bound to actin is responsible for the rigor state of themuscle. The description of the crystallographic structureof the nucleotide-free myosin head [4, 5] allowed devel-opment of a model of the working stroke with atomicresolution [6]. The myosin head consists of a large globu-

X-RAY INTERFERENCE MEASURES THE STRUCTURALCHANGES OF THE MYOSIN MOTOR IN MUSCLE WITHÅ RESOLUTIONM. Reconditi, G. Piazzesi, M. Linari, L. Lucii,Y.-B. Sun*, P. Boesecke‡, T. Narayanan‡, M. Irving*and V. Lombardi

Dipartimento di Scienze Fisiologiche, Università di Firenze,Viale G.B. Morgagni 63, I-50134 Firenze, Italy *School of Bio-medical Sciences, King’s College London, Guy’s Campus, Lon-don SE1 1UL, UK ‡ESRF, BP 220, 38043 Grenoble, France

Articolo ricevuto in redazione nel mese diMaggio 2002


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Fig. 1. Sarcomere structure. A. Longitudinal section of frog sartorious muscle as seen by electron microscopy (top) together with the diagram showingthe overlapping actin (red) and myosin (blue) filaments (adapted from H.E. Huxley, 1972 [27]). B. Antiparallel arrangement of the myosin dimers in thetwo halves of the thick filament, with a bare zone free from heads in the centre. The origin of the bare zone is indicated. C. The myosin filament (cyan)with the protruding myosin heads (blue) overlapped with a hexagonal net of six actin filaments (red). The myosin heads emerge axially as triplets with14.5 nm periodicity. In each triplet the pairs of heads are separated azimuthally by 120° and adjacent triplets are rotated by 40°, thus forming a three-stranded helix with period ~ 43 nm. Each actin filament is made by monomers assembled in a double stranded helix with period ~ 37 nm.


21


Fig. 2. Atomic model of the working stroke. Grey/brown, actin filament; red, myosin catalytic domain (residues 1–707); green, converter domain(residues 711–781); blue, long helix (residues 781–843); yellow, essential light chain; magenta, regulatory light chain. The lower myosin structure (N-free,nucleotide free, light blue long helix) shows skeletal muscle myosin bound to actin in a conformation determined by cryo-electron microscopy in the ab-sence of ATP; the upper myosin structure (ADP•AlF4

-) is derived from a smooth muscle myosin fragment with ADP•AlF4- in the active site. The catalyt-

ic domain of the ADP•AlF4- bound structure was superimposed on that of the nucleotide-free structure; only the nucleotide-free catalytic domain is

shown. The orientation of the light chain domain in the ADP•AlF4- structure was determined by superimposing residues 711–731 and 738–780 of the

converter–light chain domain complex from the nucleotide-free structure onto the corresponding converter residues in the ADP•AlF4- bound structure,

assuming that the converter–light chain complex moves as a rigid body. The Z-line of the half-sarcomere is at the bottom. Residue numbers refer tochicken skeletal myosin. From Irving et al., 2000 [18].

22



lar catalytic domain (CD, residues 1-707) that containsboth the actin binding site and the catalytic site and aslender neck region, the light chain binding domain(LCD, residues 707-843), formed by an alfa helix 9.5 nmlong that extends from the catalytic domain to the junc-tion with the rod and is stabilised by binding the twolight chains. Comparison of the crystallographic struc-ture of a fragment of the myosin head, complexed withan analogue of the ATP hydrolysis products (ADP.AlF4

-,[7]), with that of the nucleotide-free head [5] (Fig. 2) sug-gests that the release of Pi from the active site induces in-ter-domain molecular rearrangements resulting in a ~70°tilting of the LCD about the CD firmly attached to actin.Due to the length of LCD acting as a lever arm the tiltingmotion is amplified into ~ 11 nm axial displacements ofthe head-rod junction. This value is twice the length stepmeasured for one myosin encounter with actin in mostsingle molecule experiments [8, 9], but is similar to thevalue estimated with the rapid force transients that fol-low step changes in sarcomere length superimposed onisometrically contracting intact muscle fibres [10, 11].

SAXS measurements of the working strokeThe function of myosin depends on the interaction be-tween conformational changes in the motor and externalforce or motion as it occurs in the native system (the sar-comere) when the head is attached to actin, and this can-not be reproduced in crystallographic studies. Due to thequasi crystalline arrangement of the motor proteins inthe three-dimensional lattice of a muscle, small-angle X-ray scattering (SAXS) can be used to record the confor-mational changes in the myosin motor, at a lower spatialresolution than that of crystallography, but in the nativeenvironment for the motor function. In particular the in-tensity of the strong third order meridional reflection(IM3), originating from the ~14.5 nm axial repeat of themyosin heads, is sensitive to the changes in mass densityprojection of the myosin heads onto the filament that ac-company the execution of the working stroke.IM3 changes can be interpreted in terms of detailed con-formational changes by using the crystallographic mod-els. In Fig. 3 IM3 is used to measure the tilting angle be-tween the LCD and the CD in the atomic model of Fig.2. The horizontal axis in Fig. 3 shows the displacement(z) of the tip of the lever arm (the head-rod junction)produced by the tilting, thus it is related to the slidingbetween the thick and thin filament. At z= 0, that corre-sponds to the nucleotide-free structure, IM3 has a valuesimilar to that at z= 10.6 nm, corresponding to theADP.AlF4

- structure. IM3 is higher for intermediate tilt-ing and is maximum for z= 5.4 nm, when the axial coor-dinates of the centroids of the LCD and of the CD coin-cide and the axial density distribution is the narrowest.Thus changes in IM3 can be used to define the conforma-

tional changes during the myosin working stroke. In a normal contraction working strokes occur asynchro-nously, since the ensemble of myosin heads is spread outthrough the various steps of the chemo-mechanicaltransduction cycle. However, in intact single fibres iso-lated from frog muscle, the working stroke in the at-tached myosin heads can be synchronized by superim-posing, on the isometric contraction, step length pertur-bations controlled at the level of the half-sarcomere [10,12]. The drop in force simultaneous with a shorteningstep (phase 1 of Huxley and Simmons force transient),due to the elasticity of attached myosin heads and my-ofilaments, is followed by a quick recovery of force(complete within 1-2 ms, phase 2), which represents themechanical manifestation of the myosin working stroke.By repetitive synchronisation of the working stroke us-ing trains of steps of the appropriate frequency (Fig. 4A),it is possible to preserve an adequate signal:noise and re-duce the time per frame of X-ray signal to the 100 µsrange necessary to resolve the changes of IM3 during theelastic response and the subsequent execution of theworking stroke [13-15]. As shown in Fig. 4, a step releaseof 5.5 nm per half-sarcomere (B) produces a little (6 ±6%, mean ± SD) increase of IM3 (D) during the elasticdrop in force to 0.25 T0 (C). IM3 shows a large decreaseduring the quick recovery: 1 ms after the release, whenthe force has recovered to 0.66 T0, IM3 is reduced to ~0.5of its isometric value. The little change of IM3 during theelastic response suggests that z moves across the peak ofthe IM3-z relation in Fig. 3. The synchronous execution ofthe working stroke moves the experimental point down-hill along the ascending limb of the IM3-z relation. Fol-lowing a step stretch of the same size as the release, ap-

Fig. 3. Dependence of the intensity of the M3 X-ray reflection (IM3) on z.Filled circle indicates the nucleotide-free crystallographic conformationand filled square indicates the ADP•AlF4

- structure. Filled triangles,filled diamond, open circle and open square correspond to five timepoints in the experiment in Fig. 4. Adapted from Irving et al., 2000 [18].

plied 1 ms after the shortening step, the force rises toabout 1.5 T0 and then recovers towards its isometric val-ue (Fig. 4C). IM3 increases during the stretch (Fig. 4D),due to the elastic response of the heads that brings zback towards the isometric value (Fig. 3), and then un-dergoes a small decrease, during the force recovery asso-ciated with the reversal of the working stroke, due to themovement of z across the peak of the IM3-z relation. Thebest fit of the data with the IM3-z curve shows that dur-ing isometric contraction the LCD is tilted by 60° fromthe filament axis, that is 40 ° (or 7 nm, filled triangle inFig. 3) from the nucleotide-free conformation. Though the SAXS data are consistent with the tiltinglever arm model, the measurements of the extent and ofthe direction of the working stroke from the intensity

changes of the M3 reflection are strongly model-depen-dent. Moreover, the intensity of the reflection dependsalso on other parameters, such as the number of con-tributing heads and their axial and conformational disor-der. For these reasons, a completely different mechanismfor force generation cannot be excluded: the decrease inintensity of the M3 reflection during the quick recoveryfollowing a shortening step could be interpreted as wellwith increase in conformational disorder due to rapiddetachment of a fraction of heads after their spring hasbeen unloaded, followed by rapid reattachment in astrained conformation.

The X-ray interference effectWith a highly collimated beam such as that of ID2/SAXSbeamline at ESRF (Grenoble, France [16]), the myosin-based meridional reflections show a fine structure (Fig.5; [1]), due to the interference between the two arrays ofmyosin heads in each thick filament, an effect first de-scribed in the whole muscle at rest by Huxley andBrown [17]. Each half of the thick filament (Fig. 6B, blue)contains an array of 49 layers of heads (red) with regularspacing d (~14.5 nm). This array generates the M3 X-rayreflection (Fig. 6C, red). The two arrays in each thick fila-ment generate a sinusoidal interference modulation(blue) with a spatial frequency equal to the reciprocal of


23


Fig. 4. Changes in force and the intensity of the M3 X-ray reflection (IM3)produced by a shortening step and stretch separated by 1 ms during ac-tive contraction. A, Superimposed slow time base force records in thepresence and absence of the 40 length change cycles imposed at 50 ms in-tervals. Fibre cross-sectional area was 22,200 µm2 and its length was 6.75mm; the mean sarcomere length in the 2.10 mm segment was 2.09 µm.Changes in segment length (B) and force (C), in the same fibre as panel(A), sampled at 10 µs intervals, in the first part of the first length changecycle, and IM3 (D, filled circles, in 100 µs time bins) from 402 tetani in 14fibres; the noise is predominantly due to the small number of diffractedX-ray photons in each time bin. The length change measured 1 ms afterthe start of the shortening step in these fibres was 6.36±1.12 nm hs-1

(mean±SD). Dashed line: IM3 without applied length changes in the samefibres (48 tetani). Open circles were calculated from the relation in Fig. 3with ziso=7.2 nm. From Irving et al., 2000 [18].

Fig. 5. Axial X-ray diffraction patterns from a single muscle fibre at rest(A) and at the plateau of an isometric tetanus (B). Sarcomere length,2.07 µm; 6 s exposure time in both conditions. The axial pattern at restshows a series of reflections that index on the ~ 43 nm quasi-helical peri-odicity of the myosin heads in the thick filaments [17]. The reflection indi-cated by the arrow (M3) corresponds to the ~ 14.5 nm axial repeat of themyosin heads and remains intense also during the isometric contraction.

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the centre-to-centre distance between the arrays (L, theinterference distance, ~900 nm). The structure of thethick filament in Fig. 6B can be approximated by a mod-el where each layer of myosin heads is reduced to apoint diffractor at the position of its centre of mass andcan be defined by the convolution of an array of Npoints with spacing d with two points separated by L.The Fourier Transform (F.T.) of an array of N pointsspaced d is:

(1)

where Z is the reciprocal space parameter.The phase of the F.T. is set to zero by choosing the centreof mass of the array as the origin of the coordinates inthe real space. The F.T. of the whole structure is the prod-uct of the F.T. of the two separate structures, and, oncesquared, it gives the scattered intensity distributionalong the meridional direction:

(2)

The first factor of the last term in eq. (2) represents thereflection originating from the axial repeat in each array(Fig. 6B, red), and the second factor is the interferencefunction (blue). When, as in the case of the myosin fila-ment, L is much larger than d (L ~ 900 nm ~ 60 d), the re-flection is finely sampled by the interference function(Fig. 6C, black).In an isometrically contracting muscle fibre at 4 °C theM3 reflection, due to the 14.57 nm spacing of 49 layers ofheads in each array, is split into two closely spacedpeaks, at 14.47 nm and 14.66 nm (Fig. 6A). The ratio ofintensity of the high angle peak to that of the low anglepeak (IHA/ILA) is ~0.8 [1], showing that the interferencedistance is close to an odd multiple of half the 14.57 nmspacing. Due to the bipolar arrangement of the myosin heads inthe two halves of the thick filament, when actin-attachedmyosin heads execute the working stroke that pulls theactin filaments towards the centre of the sarcomere, thecentre of mass of the heads, and hence the centre of massof each array, also moves towards the centre of the sar-comere (Fig. 6E). Consequently, the interference distanceL reduces and the sinusoidal intensity distribution shiftsto a higher reciprocal spacing (rightward in Fig. 6F), de-creasing the relative intensity of the high angle peak ofthe sampled M3 reflection. If the fibre is stretched so thatthe actin filament and the catalytic domains attached toit are pulled away from the centre of the sarcomere, Land the relative intensity of the M3 high angle peak in-crease accordingly. Thus the interference method is ableto resolve the direction of the movement, independent ofa structural model for the head. The high order (~60th)by which the interference function samples the M3 re-flection increases the sensitivity of the method to Å scalemovements of the centroid of myosin heads. In Fig. 7 it

I(Z) = sin( )sin( )

sin( )sin( )

sin( )sin( )

cos ( )N Zd

Zd

ZL

ZL

N Zd

ZdZL

ππ

ππ

ππ

π

⋅

=

2 2 2

224

F.T. (Z) = sin( )sin( )

N Zd

Zd

ππ

Fig. 6. Interference fine structure of the M3 reflection and its dependenceon axial motion of the myosin heads. A, D. 2D patterns in the region ofthe M3 reflection, collected on the Image Plate detector, at the isometricplateau (A), and during the quick force recovery following a shorteningstep (D). B, E. Scheme of the two arrays of myosin heads (red) in eachmyosin filament (blue) with the LCD tilting as during the isometric con-traction (B) and following a shortening step (E). Actin filament in green.C, F. Axial X-ray intensity distribution (black) generated by the samplingof the M3 reflection (red) by the interference function (blue). To fit the ax-ial intensity distributions from A and B the interference distance L is setto 866 nm (C) and 863 nm (F) respectively.

Fig. 7. Relation between IHA/ILA and L, calculated with eq. (2) with N=49and d=14.57 nm. Triangle and circle correspond to the axial intensity dis-tribution in C and F of Fig. 6.


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Fig. 8. Changes in interference fine structure of the M3 X-ray reflection produced by rapid shortening. A, Length change (nm/hs), and force normalizedby isometric force T0. Fibre cross-sectional area, 27,300 µm2; T0, 293 kN m-2; sarcomere length, 2.13 µm. B, Axial X-ray intensity distribution of the M3 re-flection normalized to that of the lower angle peak. Colours denote the periods T0, T1 and T2 shown in A. Adapted from Piazzesi et al., 2002 [2].

26



is shown how the ratio IHA/ILA varies with L based on eq.(2), for the given d (14.57 nm) and N (49). Unlike the totalintensity of the reflection, the interference effect is insen-sitive to changes in the fraction or conformational disor-der of attached heads. These features altogether make X-ray interference the most powerful tool for testing, in thenative system, the tilting LCD model of force generationversus rapid attachment/detachment of the heads.

Interference measurement of the working strokeThe structural changes in the head accompanying themechanical working stroke were measured in a series ofexperiments at ID2/SAXS (ESRF) by recording the inter-ference changes during the elastic response and the sub-sequent quick force recovery following shortening stepsranging from 2 to 9 nm per half-sarcomere [2]. Intensityprofiles of the M3 reflection were collected in a 2-mstime frame before the length step (Fig. 8, A, B, T0, green),in a 100-µs time frame close to the end of phase 1 (T1,red) and in a 2 ms time frame near the end of phase 2(T2, blue). The shortening step reduced the value ofIHA/ILA and shifted both peaks to a higher angle (Fig. 6Dand 8B), as expected for displacement of the two arrays

of actin-attached myosin heads towards the centre of thesarcomere. Most of the change occurred at the end of theshortening step (T1) and only a small further reductionoccurred during the subsequent rapid force recoveryphase (T1 to T2 transition). The reduction is larger thelarger the size of the step, but saturates for steps largerthan 7 nm (Fig. 9). The experimental values of IHA/ILA were used to calculatethe interference distance L, using the theoretical intensitydistributions described above (Fig 6). Eq. 2 applies exact-ly if each layer of myosin heads can be considered as apoint diffractor, but parallel analysis using the mass pro-jection of the atomic model of the myosin head in the iso-metric conformation [5, 18] gave the same values ofIHA/ILA [1]. Thus the change in L responsible for thechange in IHA/ILA can be used as an estimate of the aver-age displacement (∆C) of the centres of mass of themyosin heads with respect to their attachment to themyosin filament (the tip of the LCD). As shown in Fig.10, ∆C (negative for displacements towards the center ofthe thick filament) was proportional to the size of theshortening step for steps up to 7 nm, but was about 5times smaller than the imposed filament sliding. The val-ue of ∆C at T2 (Fig. 10, blue triangles) was similar to thatat T1 (red circles). This result is consistent with models inwhich the quick force recovery is due to the workingstroke in myosin heads that remain attached to actin inphase 2. In fact, in models without working stroke, wherethe force is simply proportional to the strain in the heads,force recovery in phase 2 would be accompanied byheads binding to new actin sites farther from the centreof the myosin filament, and thus by an increase of ∆C. To make a quantitative interpretation of the observed ax-ial motions of the myosin heads during the elastic phase1 response, we must take into account the compliancesof the actin filament (0.26%/T0, [15, 19]) and of themyosin filament (0.14%/T0, [2, 15, 20, 21]). With theseparameters the axial displacements of each layer ofmyosin heads along the filament during the elastic re-sponse to length steps of different size can be calculated.The displacements are then used in the fine structuresimulation (see Methods), where each layer of myosinheads is represented by the atomic model with the CD inits nucleotide-free conformation [5, 6] and a variable tiltbetween the CD and the LCD. The changes in IHA/ILA cal-culated with this simulation are shown by the reddashed line in Fig. 9 and are much larger than the ob-served changes (red circles). The reduced changes in in-terference fine structure during the length step can beexplained if a population of heads do not respond to thelength step, although they have sufficient axial order tocontribute to the M3 reflection. These heads can be thepartner heads of those attached to actin. In this case theattached head imposes order on its partner since they

Fig. 9. Changes in IHA/ILA following shortening steps of different sizes. Redcircles (T1) and blue triangles (T2) are the means ± SEM for n=3–6 fibres, ex-cept for the T1 point at -7 nm per half-sarcomere (n=1). Green square de-notes the value for the 2-ms period before the length step (T0, Fig. 8); or-ange diamond is the value from contractions without imposed lengthsteps. The lines were calculated from the simulations described in the text:red, T1; blue, T2. Continuous lines indicate that only one head of eachmyosin responds to the length step; red dashed line (T1) indicates that allheads in the fibre respond to the step; blue dashed line (T2) indicates therapid detachment/attachment model. From Piazzesi et al., 2002 [2].

are joined at the head-rod junction. The changes inIHA/ILA during the elastic response, calculated with theaddition of the partner heads (Fig. 9, red continuousline), gave a good fit to the observed changes.According to the working stroke model, during thequick force recovery the tilt of the attached headschanges to account for the changes in the strain of actinand myosin filaments and heads themselves. The calcu-lated values for T2 interference changes (Fig. 9, blue con-tinuous line) are close to the observed data (blue trian-gles) even if the fit is not perfect. In contrast, the interfer-ence changes calculated with the rapid attachment/de-tachment model (blue dashed line) are clearly inconsis-tent with the results of the experiment, because in thiscase the centres of mass are expected to move fartherfrom the centre of the thick filament as new strainedmyosin heads are formed during rapid force recovery.The imperfect fit of the working stroke model to the ob-served fine structure at T2 may be explained by a smallfraction of heads detaching during phase 2, as alreadysuggested on the basis of changes in stiffness [12] and to-tal intensity of the M3 reflection [18] following a 5 nmshortening step. In conclusion, the X-ray interference changes measuredduring the elastic response and the subsequent rapidforce recovery following shortening steps of differentsize (2-9 nm) provide definitive evidence for a mecha-

nism of force generation based on a ~10 nm workingstroke in the myosin heads attached to actin, and againstthe idea of rapid detachment of myosin heads followedby rapid reattachment to new actin monomers.

MethodsExperimental protocol.Single fibres were dissected from the lateral head of thetibialis anterior muscle of Rana temporaria, and mountedhorizontally on a microscope stage in a chamber contain-ing Ringer’s solution. One of the fibre tendons was at-tached to a loudspeaker coil motor and the other to a ca-pacitance gauge force transducer via aluminium foil clips[22]. The resting sarcomere length was set to 2.1 µm andfibre length, width and depth were measured. The tem-perature was controlled at 4∞C. Fibres were electricallystimulated for 2.3 s at 18-25 Hz. After 0.3 s of isometriccontraction, a series of 40 shortening/stretch cycles wasimposed with a 4 ms interval between shortening andstretch and a 50-ms cycle time [14]. Sarcomere length in a1-2 mm segment near the centre of the fibre was mea-sured continuously with a striation follower [23]. The stage carrying the muscle fibre, motor and transduc-er was mounted on the high brilliance X-ray beamlineID2 at ESRF (Grenoble, France, [16]). The X-ray flux wasup to 2 x 1013 photons s-1 at wavelength 0.1 nm, and thefull width at half-maximum (FWHM) of the X-ray beamwas ca 0.1 mm vertically and 0.6 mm horizontally. Mus-cle fibres were mounted with their long axes vertical tooptimise spatial resolution. The X-ray path through theRinger’s solution was reduced to about 600 µm by plac-ing two mica windows close to the fibre. The timing ofX-ray exposures was controlled with 10-µs precision us-ing two electromagnetic shutters in series, and moni-tored using a pin diode on the backstop of the X-raycamera. X-ray data were collected on A3-size storagephosphor Image Plates (Molecular Dynamics) mountedin an evacuated camera tube 9.85 m from the fibre. Im-age plates were scanned off-line at nominal spatial reso-lution 100-µm with a Molecular Dynamics 840 scanner.The point spread function of the X-ray camera/scannercombination was measured by recording 50-µs expo-sures with the X-ray beam attenuated by 50-µm rhodi-um, and was well fitted by a Gaussian function withFWHM 320 µm in the vertical direction.Fibres were stimulated at 4 min intervals. After each pe-riod of stimulation the fibre was moved along its axis by100-250 µm to spread the effects of radiation damage.Length change cycles were imposed during stimulationusing the cyclical protocol described above. For 100 µsX-ray exposures, diffraction data were typically accumu-lated from 40 length steps in each of 20 contractions withthe unattenuated X-ray beam (total exposure 80 ms per


27


Fig. 10. Axial motions (∆C) of myosin head centroids with respect to theirmyosin filament attachments. The value of ∆C was obtained for each fi-bre and condition by fitting experimental values of IHA/ILA. A negativevalue of ∆C denotes motion towards the centre of the myosin filament.See Fig. 9 for definition of symbols. The lines were obtained by linear re-gression of all individual fibre data except the T2 points in the -9 nm perhalf-sarcomere. From Piazzesi et al., 2002 [2].

28



image plate). For 2 ms exposures, data were collectedfrom 40 length steps in each of 4 contractions with thebeam attenuated by a factor of 4. The X-ray pattern dur-ing isometric contraction was recorded with 200 ms ex-posure in each of 4 contractions with 7x beam attenua-tion. The total X-ray exposure per fibre was typicallyequivalent to 0.5 s of the unattenuated beam. Experi-ments were terminated by failure of excitation-contrac-tion coupling, and up to this point X-ray and mechanicalresponses were stable. X-ray data are presented from 18fibres with cross-sectional area 22,500 ± 5,800 µm2 (SD)

X-ray data analysis.X-ray diffraction patterns were analysed with the pro-grams HV (A. Stewart, Brandeis), Fit2D (A. Hammersley,ESRF) and Peakfit (SPSS Science). Patterns were alignedand centred using the 1,0 equatorial reflections. Thebackground under the axial X-ray reflections was sub-tracted using HV. The axial intensity distribution wascalculated by radial integration from ± 1/64 nm-1. The in-tensity distribution in the region of the M3 reflection wasfitted by two Gaussian peaks using Peakfit, with the po-sition, height and width of each peak as free parameters.The centre of mass of the M3 reflection was then calcu-lated as the intensity-weighted mean of that of the twocomponent peaks. Axial spacings were calibrated by as-suming the M3 spacing in the resting fibre to be14.340 nm [24], or that in active isometric contraction tobe 14.573 nm [1].

Simulation of the interference fine structureThe intensity profile of the M3 reflection was calculatedas the F.T. of the axial mass distribution of the myosinheads. Each myosin filament is represented as two ar-rays of 49 layers of heads symmetrical with respect tothe centre of the filament. The axial mass projection ofeach layer was calculated from crystallographic datawith the CD (heavy chain residues 1-707) of the head inthe nucleotide-free conformation [5] and the LCD (heavychain residues 707-843 and both light chains) tiltedaround the CD/LCD junction (residue 707). In the simu-lation shown in Fig. 9 we have used a distributed fila-ment compliance formalism [19, 25, 26] to calculate theforce and strain distributions along the myosin and actinfilaments. The strain in the myosin heads, representedby the tilt of the LCD with respect to the actin-boundCD, is assumed to be uniform during the steady forcedeveloped in the isometric contraction. Following thelength step the tilt (and the strain) of the heads changesaccording to the change in strain of myosin and actin fil-aments. In the working stroke model the distribution ofhead strain after a length step is calculated under theconstraint that the sarcomere length remains constantduring the quick force recovery. Simulation using the

rapid detachment/attachment model assumes that thetotal fraction of heads attached to actin remains constantand that the average head strain is proportional to force.With either models, there is no detectable difference if,instead of using heads with different strains according tothe distributed filament compliance, we use heads uni-formly spaced and with the same angle of tilt corre-sponding to the average conformation in each phase ofthe mechanical response. In this case the two arrays ofheads on the myosin filament can be represented as twoheads (or two pairs of heads) with the same tilt of theLCD, one the mirror image of the other, and with theircentres of mass separated by L, convoluted with an arrayof 49 points with spacing d. The predicted intensity dis-tribution is then the product of the intensity distributionfrom the array of points centred at the position 1/d inthe reciprocal space (see eq. 1), and the intensity distrib-ution from the two heads (or pairs of heads), that carriesinformation on both the conformation of the heads andthe position of the centres of mass and may be calculatedwith the equation:

(3)

where D is the distance between the head-rod junctionsof the two heads and xi is the coordinate of the ith residueconstituting the molecule, relative to the head-rod junc-tion. The position of the centre of mass of the head rela-tive to the head-rod junction is:

(4)

and L= D + 2C. Changes of the interference distance Lare due to either changes in the strain of the myosin fila-ment, which affects D, or changes in the tilting of theLCD, which affects C. In the first case D and, by approxi-mation, L change by the same proportion as d, so that(Eq. 2) the fine structure of the reflection does notchange. Thus only changes in L due to axial motion ofthe heads change the fine structure of the reflection.

References1. Linari, M., Piazzesi, G., Dobbie, I., Koubassova, N., Recondi-

ti, M., Narayanan, T., Diat, O., Irving, M., Lombardi, V., Proc.Natl. Acad. Sci. USA 97, 7226-7231 (2000)

2. Piazzesi, G., Reconditi, M., Linari, M., Lucii, L., Sun, Y.-B.,Narayanan, T., Boesecke, P., Lombardi, V., Irving, M. Nature415, 659-662 (2002)

3. Lymn, R.W. and Taylor, E.W. Biochem. 10, 4617-4624 (1971)4. Rayment, I., Rypniewski, W.R., Schmidt-Base, K., Smith, R.,

C = x /nii 1

n

=∑

I(Z) ∝ +

=

∑cos[ ( / )]2 21

2

πZ x Dii

n


29


Tomchick, D.R., Benning, M.M., Winkelmann, D.A., Wesen-berg, G., Holden, H.M. Science 261, 50-58 (1993)

5. Rayment, I., Holden, H.M., Whittaker, M., Yohn, C.B.,Lorenz, M., Holmes, K.C., Milligan, R.A. Science 261, 58-65(1993)

6. Geeves, M.A. and Holmes, K.C. Annu. Rev. Biochem. 68, 687-728

7. Dominguez, R., Freyzon, Y., Trybus, K.M. and Cohen, C. Cell94, 559-571 (1998)

8. Molloy, J.E., Burns, J.E., Kendrick-Jones, J., Tregear, R.T.,White, D.C. Nature 378, 209-212 (1995)

9. Mehta, A.D., Finer, J.T. and Spudich, J.A. Proc. Natl. Acad.Sci. USA 94, 7927-7931 (1997)

10. Huxley, A.F. and Simmons, R.M. Nature 233, 533-538 (1971)11. Piazzesi, G. and Lombardi, V. Biophys. J. 68, 1966-1979 (1995)12. Lombardi, V., Piazzesi, G, and Linari, M. Nature 355, 638-641

(1992)13. Irving, M., Lombardi, V., Piazzesi, G. and Ferenczi, M.A. Na-

ture 357, 156-158 (1992)14. Lombardi, V., Piazzesi, G., Ferenczi, M.A., Thirlwell, H.,

Dobbie, I., Irving, M. Nature 374, 553-555 (1995)15. Dobbie, I., Linari, M., Piazzesi, G., Reconditi, M., Koubasso-

va, N., Ferenczi, M.A., Lombardi, V., Irving, M. Nature 396,383-387 (1998)

16. Boesecke, P., Diat, O. and Rasmussen, B. Rev. Sci. Instrum. 66,1636-1638 (1995)

17. Huxley, H.E. and Brown W. J. Mol. Biol. 30, 383-434 (1967)18. Irving, M., Piazzesi, G., Lucii, L., Sun, Y.-B., Harford, J.J.,

Dobbie, I.M., Ferenczi, M.A., Reconditi, M., Lombardi, V. Na-ture Struct. Biol. 7, 482-485 (2000)

19. Linari, M., Dobbie, I., Reconditi, M., Koubassova, N., Irving,M., Piazzesi, G., Lombardi, V. Biophys. J. 74, 2459-2473 (1998)

20. Wakabayashi, K., Sugimoto, Y., Tanaka, H., Ueno, Y., Takeza-wa, Y., Amemiya, Y. Biophys. J. 67, 2422-2435 (1994)

21. Huxley, H.E., Stewart, A., Sosa, H. and Irving, T. Biophys. J.67, 2411-2421 (1994)

22. Lombardi, V. and Piazzesi, G. J. Physiol. (Lond.) 431, 141-171(1990)

23. Huxley, A.F., Lombardi, V. and Peachey, L.D. J. Physiol.(Lond.) 317, 12P-13P (1981)

24. Haselgrove, J.C. J. Mol. Biol. 92, 113-143 (1975)25. Thorson, J.W. and White, D.C.S. Biophys. J. 9, 360-390 (1969)26. Ford, L.E., Huxley, A.F. and Simmons, R.M. J. Physiol. (Lond.)

311, 219-249 (1981)27. Huxley, H.E. In The structure and function of muscle, Academic

Press Inc. (1972)

Supported by MURST, CNR and Telethon (Italy), MRC(UK), EU, EMBL and ESRF.

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Abstract The discovery of ancient artefacts and artworks that bearwitness to our cultural heritage typically raises a varietyof questions: from the correct determination of their his-torical and cultural time-frame, the place and method ofproduction, to the choice of treatments and conditionsfor restoration and preservation. A large variety of chem-ical, physical and microstructural techniques are current-ly employed to characterise objects of cultural signifi-cance, indeed the same techniques that are generally ap-plied to studies in the mineralogical and material sci-ences, and which deal with the characterisation of solid,generally inorganic matter such as; mineral, stone, ce-ramic, glass, metal, and their derivates. Neutrons, as opposed to X-rays, are the best probe forexamining the interior of thick samples. Neutron analy-sis, which is intrinsically non-invasive, is both uniqueand complementary to more conventional techniques.When sampling is not possible, neutron methods pro-vide chemical, phase specific, and microstructural infor-mation from undisturbed large volumes. Furthermore,comparison with artificially produced materials, such asmetals and alloys, can also be effectively exploited in or-der to obtain indirect information on the manufacturingtechniques of the objects under investigation. Specifically, neutron diffraction at the most modern andpowerful neutron sources and, in the future, at the newgeneration of ESS-type sources, is providing and willprovide invaluable information on cultural heritage ob-jects that must not be damaged by cutting, drilling,scraping etc. Data can be collected from large, intact ob-jects of almost any shape, and the experimental set-up isboth simple and free from sample movements. Themany-fold increment in signal and resolution affordedby the newly designed sources and instruments, will al-low element sensitive small volume phase identificationand quantification, detailed crystal structure analysis ofthe constituent phases, and direct imaging in two- andthree-dimensions by imaging and tomography tech-niques also enhanced by energy-tuning procedures.These methods can certainly provide a clearer picture ofthe technological, commercial and, more generally, his-

torical and archaeological aspects of the sample. With aview towards preservation, they can provide invaluableinformation regarding the choice of restoration and con-servation procedures. As with the mineral and Earth sciences, the potential ofneutron scattering is only recently being realised in thefields of archaeometry and preservation of cultural her-itage. With the availability of modern and future neutronsources there is much to look forward to with the open-ing of new avenues in this field of study.

1. IntroductionMost frequently, archaeometric determinations of arte-facts are obtained by methods such as electron mi-crobeam analysis and imaging, x-ray fluorescence andneutron activation analysis. These are predominantlychemical probe methods; complementary informationcan be obtained by phase analysis through diffractionmethods (x-ray, electron or neutron). However, most ofthese methods are invasive in one form or another asthey require destructive sampling techniques such ascoring, transversal sectioning, or even powdering someportion of the sample. When dealing with objects of cul-tural heritage and historical significance (prehistoricalartefacts, priceless artworks, palaeontological material)sample destruction or damage is clearly unacceptable.Consequently, much current research is aimed at devel-oping non-destructive, diagnostic techniques. Moreover, extrapolation of results taken from micro-samples to represent large objects or bulk samples isstrongly questionable. What is required is a non-invasivediagnostic technique that provides fundamental infor-mation on composition and structure from anywherewithin an antique object (i.e. penetrating deeply into thesample as well as probing a large part of its volume)which can be ideally represented by present-day, and es-pecially next generation, neutron scattering facilities.

2. Neutrons in archaeometry and conservationMicrostructure, phase identification/quantification andtexture analysis of archaeological objects by neutron dif-fraction has only recently been undertaken, but the po-

THE CONTRIBUTION OF NEUTRON SCATTERING TO CULTURAL HERITAGE RESEARCHR. Rinaldi1, G. Artioli2, W. Kockelmann3, A. Kirfel4,S. Siano5

1 Dipartimento di Scienze della Terra, Università di Perugia,I-06100 Perugia, Italy2 Dipartimento di Scienze della Terra, Università di Milano,Via Botticelli 32, I-20133 Milano, Italy

3 University of Bonn, Forschungszentrum Jülich, D-52425Jülich, Germany and ISIS Facility, UK4 Mineralogisch-Petrologisches Institut, Universität Bonn,D-53115 Bonn, Germany5 CNR - Istituto Fisica Applicata “Nello Carrara”, I-50127Firenze, Italy

Articolo ricevuto in redazione nel mese di Maggio 2002


31


tential applications of such powerful techniques spanmany fields of interest within archaeometry, conserva-tion, archaeological and natural history research, rang-ing from routine fingerprinting to complex conservationproblems. The standard diagnostic tools used today forceramics, glass, paintings, and metals are not suitable forthe characterisation of inhomogeneities at both the mi-croscopic and macroscopic scale, that would provide in-formation on thermal profiles, element distribution, mix-ing, and mechanical properties developed during manu-facture. For instance, segregation, dendritic heterogene-ity, degree of hardening and twinning, crystallinity, allrepresent fundamental aspects required for the determi-nation of the historical and cultural background of ar-chaeological findings, to correctly reconstruct their histo-ry, the manufacturing technology and to evaluate sam-ple deterioration.

Non-destructiveness in bulk. The non-destructive nature of neutron scattering experi-ments makes the technique well suited for handlinglarge, undisturbed samples and rare, unique objects,both natural and man-made, that encompasses materialsas diverse as, for instance: sediment layers, rocks, fossils,bones, ceramic, plasters, paintings, glass, metals and al-loys. The importance of good grain statistics demandsmeasurements from large samples. In stone diagnosticsin particular, where grains on the order of one mm3 arenot rare, again large samples are often required. Further-more, a generalised interpretation of analytical resultsfrom small portions of a large artwork be it stone, ceram-ic, glass, metal or other, can be highly misleading. Neu-trons offer a non-destructive diagnostic technique pro-viding fundamental information on the composition andstructure of an antique object, extending deeply into itsinterior as well as on a large part of its volume.

Direct imaging, radiography, tomography. Neutron penetration can be advantageously exploitedfor neutron imaging to determine the inner features ofmaterials and artefacts, such as composition, density andphase distributions, beyond the reach of less penetratingprobes, with specific applications in archaeology andpreservation. At present most neutron imaging is performed either bysimple neutron radiography, which exploits the absorp-tion contrast of different elements in the object to obtaintwo- and three- dimensional projections (Winkler et al.,2002), or by neutron-induced gamma activation, whichalso allows chemical analysis by measuring the decaytime of the activated species. These techniques can be very advantageously used to in-vestigate stone, ceramic and glass materials but also fres-coes and painting materials such as recently performed

at HMI Berlin for the correct attribution of some of Rem-brandt’s works from the Berlin-Dahlem Museum(Preussischer Kulturbesitz).It is expected that the neutron flux supplied by the nextgeneration of ESS-type source will enhance the quality ofimaging of artworks through the use of energy-tunednarrow (but still intense) neutron beams, so that the res-onant absorption of specific nuclei and the prompt emis-sion of gamma rays by short lived isotopes may be usedfor a 2-dimensional (radiography) or 3-dimensional (to-mography) analysis of the successive paint layers as wellas of bulkier materials. The enhancement of the attenua-tion coefficient due to coherent Bragg scattering can beexploited to provide an element sensitive signature in ra-diography and tomography (Kardjilov et al., 2002).

3. Stone materialsSurface reactivity and water content. The specific problem of stone degradation (i.e. in histori-cal buildings) needs detailed characterisation of the con-stituent materials and textures, including porosity andfluid contents. The methods and techniques are identicalto those used in the investigation of modern buildingmaterials such as cements and concretes.Water, carbon dioxide and sulphate ions are largely re-sponsible for the degradation of natural building stoneseven when present in very low concentrations; the de-tailed study of such systems on an atomic scale can sole-ly be addressed by the unique capabilities of modernneutron facilities. The breakdown, weathering and trans-formation of minerals generally involves the migrationof hydrogen through the mineral surface and into thesubsurface of the crystals. This implies volume increase,may induce oxidation and can be coupled with other ionexchange reactions or the freeze-thaw cycling. All ofthese processes change the physical properties of thenear-surface region of the minerals. As these weatheringreactions occur at the mineral/fluid or mineral/biota in-terface, a fundamental understanding of mineral surfacereactivity requires the application of light element sur-face sensitive spectroscopy and diffraction. Furthermore,reactive H2O, CO2 and SO4 must be neutralised prior topreservation.Commonly, X-rays are used in the reflective mode to in-vestigate mineral surfaces, however, neutrons are far su-perior to X-rays for direct probing of protons anddeuterons. Furthermore, rapid high-resolution, high-in-tensity neutron spectroscopy, reflectivity and diffractionare required to study the dynamics and to generate mod-els of mineral hydration, molecular binding and ion ex-change involving iso- and quasi-iso-electronic species(e.g. Ti4+-Ca2+-K+; K+-Cl-, Na+-Mg2+-Al3+-Si4+, or Fe2+-Mn2+)where X-rays fail to provide the necessary scatteringcontrast for discrimination.

32



Fig. 1. Perugia, Fontana Maggiore after restoration of the marble and limestone decorations. Conservation and preservation problems still need to beaddressed. (Photo courtesy of B. Moroni and G. Poli, Perugia)

33



Prior to any surface treatment of degrading stones andsculptures in monuments and buildings, a bulk, quanti-tative assessment of the residual H, OH and H2O contentmust be performed. This analysis must be non-destruc-tive and capable of handling/exploring large dense sam-ples while simultaneously detecting weak and/or verysubtle signals. Only the next generation of neutronsources and instrumentation will enable studies on verylow concentrations present in such samples.

Diffraction methods in archaeometry and restoration. Archaeological research based on phase, microstructureand texture analysis of artefacts and stone materials us-

ing neutrons is also relatively new but offers great poten-tial. A review of the work done by these techniques inthe field of natural stone materials can be found inSchäfer (2002). Diffraction techniques are important forhelping to date excavation sites, to establish trading pat-terns, to determine cultural exchange between regions,to elucidate historic and regional abundance, tradingnetworks and to help identify the original source of rawmaterials. Phase and microstructural characterisation ofancient objects by diffraction methods can provide sug-gestions as to the specific manufacturing techniques thatwere used. Diffraction studies, besides the issues ofsource materials may also address the alteration or cor-

Fig. 2. Time of Flight neutron dif-fraction yields information on in-tact objects such as of this smallblack-gloss Athenian-style winejug (approx. 7cm high) of un-known origin. A secondary colli-mation device or a neutron ab-sorber inside the vessel preventsneutron scattering from the backwall of the vase. The diffractionpatterns were simultaneously ob-tained with detectors at forward(a) and backscattering (b) angles.The olpe was kindly provided byDr. A..J.N.W. Prag, The Manches-ter Museum, Manchester Universi-ty, UK. The photo is the propertyof The Manchester Museum.(Kockelmann et al., 2000).

34



Fig. 3. Time of Flight diffraction patterns and Rietveld analyses from data collected at RO-TAX, ISIS, on Brühl and Siegburg ceramics (top). Characterisation of pottery fragments bymineral phase fraction ratios mullite/quartz (full columns), indicative of firing tempera-tures. The B* samples from a 13th century pottery series from Brühl are characterised by ahigh cristobalite content (hatched columns). (Kockelmann et al., 2002).

Fig. 4. Top: side (left) and bottom (right) view of an Etruscan olpe (400 BC, Museum of Chiusi, Italy) different parts of which have been analysed byquantitative multiphase analysis using TOF neutron diffraction (ISIS, ROTAX): (1) bottom wall, (2) side wall, (3) handle and (4) repair patch. Differentpeak positions indicate different tin contents while different peak widths indicate different microstructures (top, centre). Bottom: diffraction patternsand Rietveld analyses of side wall (2) and repair patch (4). (Siano et al., 2002).

35



Fig. 5. The copper axe of the Iceman (3200 BC, Ötztal, Eastern Alps) with its original handle and bindings.

Fig. 6. Experimental pole figures of a copper axe obtained by neutron diffraction at ILL .Texture analysis provides information on heat and cold treat-ments during manufacture.

36



rosion phases produced by changes in the environment(e.g. patina, black crusts, etc.).Owing to the non-destructive character of neutron tech-niques, their applicability to relatively large, intact, andprecious archaeological objects is obvious. Additionally,the large interaction volume and rapid data collectionachievable at future neutron sources will provide arange of new applications in the study and conservationof historical artefacts. TOF neutron diffraction providesnew and unique information to that from x-ray diffrac-tion. No preparation of the objects is needed and the ex-perimental set-up is simple and free of sample move-ments. Ultimately, restoration and conservation prob-lems relating to artefacts such as that reported in Figure1 can be very effectively addressed through this wide va-riety of neutron scattering techniques.

4. CeramicsCorrelations between phases or ratios of phase propor-tions, may be used to characterise or classify an artefact.During ceramics firing the starting materials undergosolid state reactions with products strongly dependentupon the firing temperature, duration and atmosphereof the process. Ancient or pre-historic ceramics fired atmoderate temperatures, often exhibit very complex dif-fraction patterns due to a wide variety of mineral phas-es, among them clay minerals and sheet silicates whichneed high intensity and resolution for identification andquantification. Neutron diffraction allows the use of thewhole artefact as sample material without disturbing itor modifying it in any way.One, fairly straightforward example of neutron diffrac-tion is provided by the patterns obtained from an undis-turbed ceramic Greek wine jug shown in Figure 2(Kockelmann et al., 2000).Another example of the application of fingerprinting isthat of medieval German ceramics from Siegburg andBrühl, two prominent sites for stoneware developmentand production in the Middle Ages, where the presenceof cristobalite is characteristic of Brühl pottery. Charac-terisation of pottery fragments by mineral phase frac-tions derived by Rietveld analysis of TOF neutron dif-fraction is shown in Figure 3 (Kockelmann et al., 2001).

5. Metal artefactsMaterials and metals in particular, change their micro-scopic structure as a result of mechanical or thermaltreatments during manufacturing. This implies that astructural analysis by neutron diffraction may give valu-able information about ancient production processes. This has been demonstrated by TOF neutron diffractionanalysis in the case of an Etruscan bronze vessel (Figure

4). The compositions of the bottom and the wall of theobject were determined to be typical for classical bronzeswith 90% copper and 10% tin. Interestingly, a significantamount of lead was found in the handle, and a repairpatch at the base of the vessel revealed a considerabledegree of corrosion as indicated by the detection of asubstantial amount of cuprite (copper oxide). Further-more, from detailed analysis of the diffraction peak pro-files it was possible to distinguish the underlying origi-nal bronze from the patch material which is almost purecopper.More information is obtained by Rietveld refinementanalysis of the peak profiles and comparison with analo-gous spectra from modern reference samples producedunder controlled conditions. Raw casting of the jug’shandle is indicated by broad and structured bronzepeaks, whereas the much narrower peaks of the wallsuggest partial recrystallisation by mechanical and ther-mal treatment. These results are important because themanufacturing techniques of such small vessels are notyet entirely understood.Neutron diffraction is particularly powerful for theanalysis of the interior of materials, such as stackings ofmetal sheet, coins with coatings, or objects located insidesealed containers. There is further potential of neutrondiffraction for investigating the volume textures andgrain distributions of metal objects. Texture is a casestudy of its own and is an important characteristic formechanically treated archaeological artefacts. The graindistributions in coins for example could be used to dis-criminate authentic objects from forgeries or fakes, or todistinguish between differently struck coins.A very recent example concerning the interpretation ofmetal textures is the analysis of Copper Age axes per-

Fig. 7. Neutron scattering can provide information on microstructure,phase composition and texture, of undisturbed archaeological objects.The capabilities of next generation neutron sources promise to yield im-ages of inner fabrics, such as those reported in the figure (obtained bySEM and XRD), through the two- but also the three-dimensional recon-struction of signals collected without sampling the object or samplepreparation.

37



formed by neutron diffraction. Among others, theunique copper axe found together with the mummifiedbody of the 5200 years old Iceman (Ötztal Mountains,Eastern Alps) was analysed by neutron diffraction tech-niques at the ILL (Figure 5). This is the only prehistoricaxe ever found with the original handle and bindings.Full, non-destructive texture analysis has proven thattextural information can be successfully extracted fromthe diffraction data irrespective of the shape of the ob-ject, and that the specific manufacturing history of eachaxe can be derived (Figure 6).

6. Forecast of novel opportunities at next generation Neutron SourcesNeutron diffraction represents a very promising ar-chaeometric tool and the knowledge of its potential inthe examination of artefacts of nearly all shapes and ma-terials in a truly non-destructive manner is still at a veryearly stage of exploitation by the relevant science com-munity. The examples of neutron studies on artefactsand archaeological objects presented here are all very re-cent and some of the achievements are still far from thegoals envisaged, mainly due to limitations of presentneutron sources and instrumentations. The next genera-tion of neutron sources promises to provide all the infor-mation on phase composition, inner fabric and texturefor undisturbed art objects such as envisaged in Figure 7.The unique capabilities offered by an ESS-class neutronsource as regards intensity and the corresponding ad-vancements in time-of-flight instruments will allow thesimultaneous detection of weak and/or very subtle sig-nals and will enable combined analyses of phase identi-fication, phase fraction, microstructure and texture onboth, very small and large objects. Referring to the exam-ples given here, the proposed ESS neutron source will al-low neutron studies beyond current thresholds in thefollowing areas: - Phase and microstructural characterisation of stones

and ceramics by investigating large suites of site-spe-cific objects and, for comparison purposes, also ofwell-defined reference samples in a reasonable timeand finally on a routine basis.

- Combined texture and microstructure analysis ofmetallic objects, such as the Iceman axe, in order to getcomplementary information on the manufacturingconditions by analyses of grain size and strain as wellas preferred orientation of crystallites, again also oncomparative samples obtained by different manufac-turing processes.

- Texture analysis of precious and large or heavy objectsin a complete stationary experimental set-up which ispossible only at TOF-instruments with a wide three-dimensional detector arrangement surrounding theobject.

This paper draws upon the Report on Cultural Heritage pre-sented at the ESS European Conference in Bonn, Germany16-17 May, 2002. available on the web site: http://www.ess-europe.de

References

1. Kardjilov, N., Baechler, S., Lehmann, E., Frei, G. (2002) Ap-plied energy-selective neutron radiography and tomographywith cold neutrons. ESS European Conference, AbstractBook, p.137. Web site: http://www.ess-europe.de.

2. Kockelmann, W., Kirfel, A., Hähnel, E. (2001) Non-destruc-tive phase analysis of archaeological ceramics using tof neu-tron diffraction, J. Archaeological Science, 28, 213-222.

3. Kockelmann, W., Pantos, E., Kirfel, A. (2000) Radiation in Artand Archaeometry Edited by: D.C. Creagh, D.A. Bradley. El-sevier Science B.V., ISBN: 0-444-50487-7, p. 347-377

4. Schäfer, W. (2002). Neutron diffraction applied to geologicaltexture and stress analysis. Eur. J. Mineral. 14/II, 263-290.

5. Siano, S., Kockelmann, W., Bafile, U., Celli, M., Iozzo, M.,Miccio, M., Moze, O., Pini, R., Salimbeni, R., Zoppi, M.(2002) Quantitative multiphase analysis of archaeologicalbronzes by neutron diffraction, Applied Physics A, in print.

6. Winkler, B., Knorr, K., Kahle, A., Vontobel, P., Lehman, E.,Hennion, B., Bayon, G. (2002) Neutron imaging and neutrontomography as non-destructive tools to study bulk rocksamples. Eur. J. Mineral. 14/II, 349-354.

38


PROGETTO E.S.S.

The ESS project proposal was presented at the EuropeanSource of Science conference in Bonn, in the formerHouse of Parliament of the Federal Republic of Germanyfrom 15-17 May 2002. More than 750 scientists from 22 European countries at-tended the conference and its satellite meetings. The to-tal number of participants was around 900. The confer-ence presents an important milestone for the ESS project.The proposal and science case is now in place and wehave entered the decision phase for the ESS. Providedthe decision to build is taken within the year 2003 or ear-ly 2004, the ESS may be in operation in the year 2011. After words of welcome from the Chairman of the ESSCouncil, P.Tindemans, the Secretary of State of Nord-Rhein Westfalia, H. Krebs, on behalf of the Prime Minis-ter W. Clement, spoke about the advantages and attrac-tiveness - to any region in Europe - of hosting the ESS fa-cility. He underlined this statement effectively by report-ing that NRW was prepared to contribute 10% of the fullESS construction budget if NRW was selected to host theESS facility. The need for investment in Large scale facilities in gener-al and the ESS in specific was prominently stated in thetalks of Prof. E. Banda from the European Science Foun-dation and Prof. B. Cywinski from the European Neu-tron Scattering Association. The two speakers also referred to the OECD recommen-dation to build a third generation neutron source in eachof the three major economic regions: America, Asia andEurope. A recommendation that only Europe lacks to fol-low. The 30 year European lead in the field of neutronscattering is threatened by the US and Japanese projectsthat will deliver their first neutrons in 2006 and 2007 andclaim World leadership a couple of years later.The general science case for the ESS, with strong empha-sis on the new opportunities ESS will provide in a verybroad range of disciplines, was convincingly presentedby D. Richter the chairman of the ESS-SAC. The ESSTechnical Project was presented by the ESS-Project Di-rector J.-L. Laclare. Three specific examples of the scien-tific opportunities with the ESS in three key technologi-cal areas were described by three eminent scientists: Ph.Whiters on Engineering, G.Aeppli on Information Tech-nology and O.Byron on Biotechnology.On May 17, seven scientific talks demonstrated how thehuge step in source quality provided by the ESS wouldallow completely new scientific and technological prob-lems to be addressed in these seven fields of scienceranging from fundamental physics to biology, from in-formation technology to engineering and sustainable de-velopment. The ESS will be an extremely versatile tool.

On May 15, a number of satellite meetings took place.The German Neutron Society held its 2002 annual meet-ing in the Wasserwerk, the building used by the Germanparliament during the re-construction of the Bundeshausin Bonn; other neutron scattering societies organizedsimilar meetings: the Czech, Slovak, Dutch, Italian,Swiss and the Polish neutron societies all met in Bonn assatellite meetings. The board of the Italian, French andScandinavian neutron scattering societies also met inBonn. All the European communities are strongly infavour of the construction of the ESS. The EU supported neutron related instrumentation de-velopment networks in particular, ENPI, DLAB, e-VER-DI, SCANS, TECHNI and VESUVIO also wanted to ex-press their interests in the ESS, by arranging their annualmeetings as a satellite event on May 15 in Bonn. TheNeutron Round Table used the opportunity to organise ajoint RTD network meeting with all the networks coordi-nators. Two major European neutron user facilities didwant to be present in Bonn and had their annual usermeeting as satellite meetings of the ESS European Con-ference.The event was followed by 50 journalists from the majorEuropean countries and a press conference was orga-nized on May 16, 2002. Moreover, 10 companies from 6European countries were present in Bonn with theirproducts, demonstrating the industrial competencewithin Europe to construct the ESS facility.Five different regions in Europe 1) Yorkshire and 2) Ox-fordshire in the UK, 3) Sachsen and Sachsen-Anhalt and4) Nord-Rhein Westfalia in Germany and 5) a Scandina-vian consortium, presented their interest to host the ESS,in very impressive documentations and stands at theconference. In conclusion, the ESS project has entered a new phase.The ESS science case is now accepted as strong and wellpresented, the chosen technical solution has beendeemed convincing and within the capability of Euro-pean industry and the institutions behind the ESS pro-ject. The ESS facility will be the premier neutron sourcein the World – about an order of magnitude better thanthe US and Japanese projects. In short: The ESS project isready and timely – we can do it! – the next step is to in-duce the European governments and the EU to arrive ata decision that will allow us realise the ESS.

F. CarsughiESS Central Project Team

PRESENTATION OF THE EUROPEAN SPALLATION SOURCE (ESS) PROPOSAL

39


25 giugno - 16 agosto 2002 VARENNA, ITALY

International School of Physics “Enrico Fermi” -Courses 2002http://www.sif.it/sif/sif/varenna/2002-courses.html

15-20 luglio 2002 ERICE, ITALY

Euroconference Quantum Phases at the Nanoscale(Nanophase)

20 luglio - 1 agosto 2002 ERICE, ITALY

New Trends in Mesoscopic Physics (TowardsNanoscience)

4 - 6 agosto 2002 VILLIGEN, SWITZERLAND

Neutron and Synchrotron X-ray Scattering inCondensed -Matter Research (NSCMR2002)http://www.psi.ch/sls/NSCmr2002

25-29 agosto 2002 VENEZIA, ITALY

XII International Conference on Small Angle Scattering A satellite Conference of the 19th IUCR Congresshttp://www.infm.it

7-12 settembre 2002 SAN FELIU DE G., SPAIN

Euresco Conference - Computational Biophysics:Integrating Theoretical Physics and Biology. From theElectronic to the Mesoscale.

11-14 settembre 2002 TRENTO, ITALY

XVI Congresso Nazionale della Società Italiana diBiofisica Pura e Applicata e I Workshop di BiofisicaItaliano-Slovenohttp://www.science.unitn.it/SIBPA2002/

15-20 settembre 2002 BRATISLAVA, SLOVAKIA

International Conference on Thin Filmshttp://www.ictf12.savba.sk

23-28 settembre 2002 FRASCATI, ITALY

School and Workshop on Nanotubes andNanostructureshttp://www.lnf.infn.it/conference/nn2002

23 settembre - 3 ottobre 2002 PALAU, ITALY

VI Scuola di Spettroscopia Neutronica “Francescopaolo Ricci” (I Neutroni come Sonda Microscopica diSistemi Disordinati)http://www.sisn.it

12-14 dicembre 2002 GRENOBLE, FRANCE

Workshop on the prospectives in Single CrystalNeutron Spectroscopy (SCNS)http://www.ill.fr/Events/ONSITE/SCNS/index.htmle-mail [email protected]

4-7 agosto 2003 VENEZIA, ITALY

Polarised Neutrons and Synchrotron X-rays forMagnetism.A satellite of the International Conference of Magnetism,Rome 2003.http://venice.infm.ithttp://www.icm2003.mlib.cnr.it

CALENDARIO

40


VARIE

VI Scuola di Spettroscopia Neutronica‘‘Francesco Paolo Ricci’’

I neutroni come sonda microscopica di sistemi disordinati

Hotel Capo d’Orso - Località Cala Capra, Palau (SS)23 settembre - 3 ottobre 2002

DOCENTIA. Albinati Università di MilanoU. Balucani IFAC-CNR, FirenzeC. J. Carlile ILL, GrenobleD. Colognesi IFAC-CNR, FirenzeA. Deriu Università di ParmaB. Dorner ILL, GrenobleJ. Eckert Los Alamos National LaboratoriesE. Guarini INFM, FirenzeG. J. Kearley IRI, Technische Universiteit DelftR. Lechner HMI, BerlinA. Paciaroni Università di PerugiaM. A. Ricci Università di Roma TreF. Sacchetti Università di PerugiaR. Senesi Università di Roma Tor VergataJ.-B. Suck Universität ChemnitzG. Zerbi Politecnico di MilanoM. Zoppi IFAC-CNR, Firenze

• La Scuola si articola in lezioni di carattere generale, lezioni applicative ed esercitazioni in piccoli gruppi di studentisotto la guida di tutors.

• Il numero degli studenti è limitato a 30. Persone con precedente esperienza nel campo potranno essere ammessecome osservatori.

• Il costo di partecipazione di 700 comprende lezioni ed esercitazioni pratiche ed il trattamento di pensione com -pleta presso l’Hotel Capo d’Orso (www.delphina.it/orso.htm) per tutta la durata della Scuola. E’ disponibile un cer-to numero di borse a copertura del costo di partecipazione.

• La domanda di iscrizione, da inoltrare entro il 30 Giugno 2002, deve essere fatta compilando il modulo di parteci-pazione reperibile all’indirizzo www.sisn.it. L’accettazione delle iscrizioni, e della eventuale assegnazione dellaborsa, verrà comunicata entro il 31/07/2002.

SCADENZA PER LE ISCRIZIONI 30 Giugno 2002

Direttori: Caterina Petrillo, Dipartimento di Fisica, Politecnico di Milano, e INFM – Ubaldo Bafile, Istituto di Fisica Applicata“Nello Carrara”, CNR, Firenze

Segreteria: Grazia Ianni, Istituto di Struttura della Materia, CNR, Sede di Roma Montelibretti, Area della Ricerca di Roma, ViaSalaria, km 29,300 - 00016 Monterotondo Scalo (RM) - Tel: 06 90672285, Fax: 06 90672316, e-mail: [email protected]

Si ringrazia il Dipartimento di Chimica dell’Università di Sassari per aver contribuito al finanziamento della Scuola

CONSIGLIO NAZIONALEDELLE RICERCHE

ISTITUTO NAZIONALE PER LAFISICA DELLA MATERIA

41


VARIE

VI Scuola di Spettroscopia Neutronica‘‘Francesco Paolo Ricci’’

I neutroni come sonda microscopica di sistemi disordinati

Hotel Capo d’Orso - Località Cala Capra, Palau (SS)23 settembre - 3 ottobre 2002

MODULO DI ISCRIZIONE

Nome: ......................................................... Cognome: ...................................................................................................

Posizione attuale (laureando, dottorando, borsista, etc.): .................................................................................................

...........................................................................................................................................................................................

Affiliazione: .....................................................................................................................................................................

...........................................................................................................................................................................................

Indirizzo: ...........................................................................................................................................................................

Telefono: .............................................................. Fax: ...................................................................................................

e-mail: ...............................................................................................................................................................................

Campo di attività:..............................................................................................................................................................

...........................................................................................................................................................................................

...........................................................................................................................................................................................

Richiede una borsa a copertura del costo di partecipazione (No | Parziale | Totale):

...........................................................................................................................................................................................

Arrivo (nave | aereo): ........................................... Ore: ................................................

Partenza (nave | aereo): ........................................ Ore: ................................................

Il modulo di iscrizione deve essere inviato entro il 30 giugno 2002 alla segreteria della Scuola, preferibilmente perposta elettronica. Qualunque comunicazione agli iscritti sarà effettuata per posta elettronica all’indirizzo indicato nelmodulo. Si prega di comunicare eventuali variazioni.L’arrivo e la registrazione avranno luogo nel pomeriggio di lunedì 23 settembre. La Scuola termina la mattina digiovedì 3 ottobre.

Segreteria: Sig.ra Grazia Ianni,Istituto di Struttura della Materia, CNR, Sede di Roma MontelibrettiArea della Ricerca di Roma, Via Salaria, km 29,30000016 Monterotondo Scalo (RM)Tel: 06 90672285, Fax: 06 90672316e-mail: [email protected]

42


Scadenze per richieste di tempo macchina presso alcuni laboratori di Neutroni

ISISLa scadenza per il prossimo call for proposalsè il 16 ottobre 2002 e il 16 aprile 2003

ILLLa scadenza per il prossimo call for proposalsè il 22 settembre 2002 e il 24 febbraio 2003

LLB-ORPHEE-SACLAYLa scadenza per il prossimo call for proposalsè il 1 ottobre 2002per informazioni: Secrétariat Scientifique du LaboratoireLéon Brillouin, TMR programme, Attn. Mme C. Abraham, Laboratoire Léon Brillouin,CEA/SACLAY, F-91191 Gif-sur-Yvette, France.Tel: 33(0)169086038; Fax: 33(0)169088261 e-mail: [email protected]://www-llb.cea.fr

BENSCLa scadenza è il 15 settembre 2002 e il 15 marzo 2003

RISØ E NFLLa scadenza per il prossimo call for proposalsè il 1 aprile 2003

Scadenze per richieste di tempo macchinapresso alcuni laboratori di Luce di Sincrotrone

ALSLe prossime scadenzesono il 15 marzo 2003 (cristallografia macromolecolare)e il 1 giugno 2003 (fisica)

BESSYLe prossime scadenzesono il 4 agosto 2002 e il 15 febbraio 2003

DARESBURYLa prossima scadenzaè il 31 ottobre 2002 e il 30 aprile 2003

ELETTRALe prossime scadenzesono il 31 agosto 2002 e il 28 febbraio 2003

ESRFLe prossime scadenzesono il 1 settembre 2002 e il 1 marzo 2003

GILDA(quota italiana) Le prossime scadenzesono il 1 novembre 2002 e il 1 maggio 2003

HASYLAB(nuovi progetti) Le prossime scadenzesono il 1 settembre 2002, il 1 dicembre 2002 e il1 marzo 2003

LURELa prossima scadenza è il 30 ottobre 2002

MAX-LABLa scadenza è approssimativamente febbraio 2003

NSLSLe prossime scadenzesono il 30 settembre 2002, il 31 gennaio 2003 e il 31maggio 2003

SCADENZE

43


ALS Advanced Light SourceMS46-161, 1 Cyclotron Rd Berkeley, CA 94720, USAtel:+1 510 486 4257 fax:+1 510 486 4873http://www-als.lbl.gov/Tipo: D Status: O

AmPS Amsterdam Pulse StretcherNIKEF-K, P.O. Box 41882, 1009 DB Amsterdam, NLtel: +31 20 5925000 fax: +31 20 5922165Tipo: P Status: C

APS Advanced Photon SourceBldg 360, Argonne Nat. Lab. 9700 S. Cass Avenue, Ar-gonne, Il 60439, USAtel:+1 708 252 5089 fax: +1 708 252 3222http://epics.aps.anl.gov/welcome.htmlTipo: D Status: C

ASTRIDISA, Univ. of Aarhus, Ny Munkegade, DK-8000 Aarhus, Denmarktel: +45 61 28899 fax: +45 61 20740Tipo: PD Status: O

BESSY Berliner Elektronen-speicherring Gessell.für Synchro-tron-strahlung mbHLentzealle 100, D-1000 Berlin 33, Germanytel: +49 30 820040 fax: +49 30 82004103http://www.bessy.deTipo: D Status: O

BSRL Beijing Synchrotron Radiation Lab.Inst. of High Energy Physics, 19 Yucuan Rd.PO Box 918,Beijing 100039, PR Chinatel: +86 1 8213344 fax: +86 1 8213374http://solar.rtd.utk.edu/~china/ins/IHEP/bsrf/bsrf.htmlTipo: PD Status: O

CAMD Center Advanced Microstructures & DevicesLousiana State Univ., 3990 W Lakeshore, Baton Rouge,LA 70803, USAtel:+1 504 3888887 fax: +1 504 3888887http://www.camd/lsu.edu/Tipo: D Status: O

CHESS Cornell High Energy Synchr. Radiation SourceWilson Lab., Cornell University Ithaca, NY 14853, USAtel: +1 607 255 7163 fax: +1 607 255 9001http://www.tn.cornell.edu/

Tipo: PD Status: ODAFNEINFN Laboratori Nazionali di Frascati, P.O. Box 13,I-00044 Frascati (Rome), Italytel: +39 6 9403 1 fax: +39 6 9403304http://www.lnf.infn.it/Tipo:P Status: C

DELTAUniversität Dortmund,Emil Figge Str 74b,44221 Dortmund, Germanytel: +49 231 7555383 fax: +49 231 7555398http://prian.physik.uni-dortmund.de/Tipo: P Status: C

ELETTRASincrotrone Trieste, Padriciano 99, 34012 Trieste, Italytel: +39 40 37581 fax: +39 40 226338http://www.elettra.trieste.itTipo: D Status: O

ELSA Electron Stretcher and AcceleratorNußalle 12, D-5300 Bonn-1, Germanytel:+49 288 732796 fax: +49 288 737869http://elsar1.physik.uni-bonn.de/elsahome.htmlTipo: PD Status: O

ESRF European Synchrotron Radiation Lab.BP 220, F-38043 Grenoble, Francetel: +33 476 882000 fax: +33 476 882020http://www.esrf.fr/Tipo: D Status: O

EUTERPECyclotron Lab.,Eindhoven Univ. of Technol, P.O.Box 513,5600 MB Eindhoven, The Netherlandstel: +31 40 474048 fax: +31 40 438060Tipo: PD Status: C

HASYLABNotkestrasse 85, D-2000, Hamburg 52, Germanytel: +49 40 89982304 fax: +49 40 89982787http://www.desy.de/pub/hasylab/hasylab.htmlTipo: D Status: O

INDUS Center for Advanced Technology, Rajendra Nagar, In-dore 452012, Indiatel: +91 731 64626

L U C E D I S I N C R OT R O N ESYNCHROTRON SOURCES WWW SERVERS IN THE WORLD(http://www.esrf.fr/navigate/synchrotrons.html)

FACILITIES

44


FACILITIES

Tipo: D Status: C

KEK Photon FactoryNat. Lab. for High Energy Physics, 1-1, Oho,Tsukuba-shi Ibaraki-ken, 305 Japantel: +81 298 641171 fax: +81 298 642801http://www.kek.jp/Tipo: D Status: O

KurchatovKurchatov Inst. of Atomic Energy, SR Center,Kurchatov Square, Moscow 123182, Russiatel: +7 95 1964546Tipo: D Status:O/C

LNLS Laboratorio Nacional Luz SincrotronCP 6192, 13081 Campinas, SP Braziltel: +55 192 542624 fax: +55 192 360202Tipo: D Status: C

LUREBât 209-D, 91405 Orsay ,Francetel: +33 1 64468014; fax: +33 1 64464148E-mail: [email protected]://www.lure.u-psud.frTipo: D Status: O

MAX-LabBox 118, University of Lund, S-22100 Lund, Swedentel: +46 46 109697 fax: +46 46 104710http://www.maxlab.lu.se/Tipo: D Status: O

NSLS National Synchrotron Light SourceBldg. 725, Brookhaven Nat. Lab., Upton, NY 11973, USAtel: +1 516 282 2297 fax: +1 516 282 4745http://www.nsls.bnl.gov/Tipo: D Status: O

NSRL National Synchrotron Radiation Lab.USTC, Hefei, Anhui 230029, PR Chinatel:+86 551 3601989 fax:+86 551 5561078Tipo: D Status: O

PohangPohang Inst. for Science & Technol., P.O. Box 125 Po-hang, Korea 790600tel: +82 562 792696 f +82 562 794499Tipo: D Status: C

Siberian SR CenterLavrentyev Ave 11, 630090 Novosibirsk, Russiatel: +7 383 2 356031 fax: +7 383 2 352163Tipo: D Status: O

SPring-8

2-28-8 Hon-komagome, Bunkyo-ku ,Tokyo 113, Japantel: +81 03 9411140 fax: +81 03 9413169Tipo: D Status: CSOR-RING Inst. Solid State PhysicsS.R. Lab, Univ. of Tokyo, 3-2-1 Midori-cho Tanashi-shi,Tokyo 188, Japantel: +81 424614131 ext 346 fax: +81 424615401Tipo: D Status: O

SRC Synchrotron Rad. CenterUniv.of Wisconsin at Madison, 3731 Schneider Dri-veStoughton, WI 53589-3097 USAtel: +1 608 8737722 fax: +1 608 8737192http://www.src.wisc.eduTipo: D Status: O

SRRC SR Research Center1, R&D Road VI, Hsinchu Science, Industrial Parc,Hsinchu 30077 Taiwan, Republic of Chinatel: +886 35 780281 fax: +886 35 781881http://www.srrc.gov.tw/Tipo: D Status: O

SSRL Stanford SR LaboratoryMS 69, PO Box 4349 Stanford, CA 94309-0210, USAtel: +1 415 926 4000 fax: +1 415 926 4100http://www-ssrl.slac.stanford.edu/welcome.htmlTipo: D Status: O

SRS Daresbury SR SourceSERC, Daresbury Lab, Warrington WA4 4AD, U.K.tel: +44 925 603000 fax: +44 925 603174E-mail: [email protected]://www.dl.ac.uk/home.htmlTipo: D Status: O

SURFB119, NIST, Gaithersburg, MD 20859, USAtel: +1 301 9753726 fax: +1 301 8697628http://physics.nist.gov/MajResFac/surf/surf.htmlTipo: D Status: O

TERAS ElectroTechnical Lab.1-1-4 Umezono, Tsukuba Ibaraki 305, Japantel: 81 298 54 5541 fax: 81 298 55 6608Tipo: D Status: O

UVSORInst. for Molecular ScienceMyodaiji, Okazaki 444, Japantel: +81 564 526101 fax: +81 564 547079Tipo: D Status: O

D = macchina dedicata; PD = parzialmente dedicata; P = in parassitaggio.

O= macchina funzionante; C=macchina in costruzione.

D = dedicated machine; PD = partially dedicated; P = parassitic.

O= operating machine; C= machine under construction.

45


FACILITIES

Atominstitut Vienna (A)Facility: TRIGA MARK IIType: Reactor. Thermal power 250 kW. Flux: 1.0 x 1013

n/cm2/s (Thermal); 1.7 x 1013 n/cm2/s (Fast)Type of instruments available to external users:SANS, Interferometer, Depolarisation, TransmissionExpts, neutron radiography.Address for information:Atominstitut Oesterreichischen UniversitaetenStadionallee 2 A-1020 WienProf. H. RauchTel: +43 1 58801 14168; Fax: +43 1 58801 141199E-mail: [email protected]://www.ati.ac.at

BNL (USA)Brookhaven National Laboratory, Biology Department,Upton, NY 11973, USADieter Schneider;General Information: Rae Greenberg;Tel: +1 516 282 5564 Fax: +1 516 282 5888http://neutron.chm.bnl.gov/HFBR/

Budapest Neutron Centre BRR (H)Type: Reactor. Flux: 2.0 x 1014 n/cm2/sNumber of instruments available to external users: 9Type of instruments available to external users: 1 powder/liquid diffractometer; 1 single crystaldiffractometer*; 1 SANS; 1 reflectometer*; 2 3-axisspectrometers; 2 Neutron gamma activation analysis* Under construction.Dates for proposal submission: June 15/November 15Date for selection process: July/DecemberRelated scheduling periods: August-December/January-June.Address for application forms:Dr. Borbely Sándor, KFKI Building 10, 1525 Budapest, Pf 49, HungaryE-mail: [email protected]://www.iki.kfki.hu/nuclear

FRJ-2 Forschungszentrum Jülich (D)Type: Dido reactor. Flux: 2 x 1014 n/cm2/sNumber of instruments available to external users: 15Type of instruments available to external users: 2 powder/liquid diffractometers; 2 single crystaldiffractometers; 2 SANS; 1 duble crystal diffractometer; 3 3-axis spectrometers; 1 quasielastic diffractometer; 1TOF (MET); 2 backscattering spectrometers; 1 β-NMRDates for proposal submission: no formal selectionprocess.Informal proposals to:Prof. D. Richter, Forschungszentrums Jülich GmbH,Institut für Festkörperforschung, Postfach 19 13, 52425Jülich, GermanyTel: +49 2461161 2499; Fax: +49 2461161 2610E-mail: [email protected]://www.kfa-juelich.de

FRG-1 Geesthacht (D)Type: Swimming Pool Cold Neutron Source. Flux: 8.7 x1013 n/cm2/sNumber of instruments available to external users: 10Type of instruments available to external users: 1 four circle texture diffractometer; 2 residual stressdiffractometers; 2 SANS; 2 reflectometers; 1 TOFspectrometer for basic research; 2 duble crystaldiffractometer for high resolution SANS; 1 3-dimens.polarisation analysis diffractometer.Polarised neutrons available on 5 instrumentsDates for proposal submission: any timeDates for selection process: within 4 weeks ofsubmissionAddress for application forms and informations:Reinhard Kampmann, Institute for Materials Science,Div. Wfn-Neutronscattering, GKSS, Research Centre,21502 Geesthacht, GermanyTel: +49 (0)4152 87 1316/2503; Fax: +49 (0)4152 87 1338E-mail: [email protected]://www.gkss.de

N E U T R O N INEUTRON SCATTERING WWW SERVERS IN THE WORLD(http://www.isis.rl.ac.uk)

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FACILITIES

HMI Berlin BER-II (D)Facility: BER II, BENSCType: Swimming Pool Reactor. Flux: 2 x 1014 n/cm2/sNumber of instruments available to external users: >17Type of instruments available to external users: 2 powder/liquid diffractometers; 3 3-axis spectrometers; 4 single crystal diffractometers; 1 quasielasticspectrometer; 1 membrane diffraction; 2 TOF (MET); 2SANS; 1 spin echo; 1 reflectometer; 1 neutroninterferometer; 1 β-NMR; 1 cold source.NB: for many instruments options include polarisation,high fields, high pressures and low temperatures.Dates for proposal submission: 15 March/15 SeptemberDates for selection process: May/NovemberRelated scheduling periods: July-December/January-JuneAddress for application forms:Dr. Rainer Michaelsen, BENSC, Scientific Secretary,Hahn-Meitner-Insitut, Glienicker Str 100, 14109 Berlin,GermanyTel: +49 30 8062 2304/3043; Fax: +49 30 8062 2523/2181E-mail: [email protected]://www.hmi.de/

IBR2 Dubna (RU)Type: Pulsed Reactor. Flux: 3 x 1016 (thermal n in core)Number of instruments available to external users: 12Type of instruments available to external users: 4 powder/liquid diffractometers; 1 single crystaldiffractometer; 1 SANS; 2 reflectometers; 1 quasielasticspectrometer; 2 TOF (MET); 1 spin echo.Dates for proposal submission: 16 October/16 MayDates for selection process: 30 January/15 SeptemberRelated scheduling periods: February-June/October-FebruaryAddress for application forms:Dr. Vadim Sikolenko, Frank Laboratory of NeutronPhysics, Joint Institute for Nuclear Research, 141980Dubna, Moscow Region, Russia.Tel: +7 09621 65096; Fax: +7 09621 65882E-mail: [email protected]://nfdfn.jinr.dubna.su/

ILL Grenoble (F)Type: 58MW High Flux Reactor. Flux: 1.5 x 1015 n/cm2/sNumber of instruments available to external users: 36Type of instruments available to external users: 5 powder/liquid diffractometers; 7 single crystaldiffractometers; 2 SANS*; 3 reflectometers*; 5 polarisedneutron instruments*; 2 Nuclear Physics; 6 3-axisspectrometers; 2 backscattering spectrometers; 3 TOF(MET); 2 spin echo; 2 Fudamental Physics.* Some double countingNB: 7 of the above instruments are operated andsupported by Collaborative Research Groups (CRGs)Dates for proposal submission: 15 February/31 AugustDates for selection process: April/OctoberRelated scheduling periods: July-Decem./January-JuneAddress for application forms:Dr. H. Büttner, Scientific Coordination Office, ILL, BP156, 38042 Grenoble Cedex 9, FranceTel: +33 4 7620 7179; Fax: +33 4 76483906E-mail: [email protected]://www.ill.fr

IPNS (USA)Argonne National Laboratory, 9700 South Cass Avenue,Argonne, IL 60439-4814, USAP.Thiyagarajan,Bldg.200,RM. D125;tel :+1 708 9723593 E-mail: THIYAGA@ANLPNSErnest Epperson, Bldg. 212;tel: +1 708 972 5701 fax: +1 708 972 4163 or + 1 708 972 4470 (Chemistry Div.)http://pnsjph.pns.anl.gov/ipns.html

IRI Delft (NL)Type: 2MW light water swimming pool. Flux: 1.5 x 1013

n/cm2/sNumber of instruments available to external users: 5+2*Type of instruments available to external users: 2 powder/liquid diffractometers*; 1 reflectometer; 1small angle scattering spectrometer*; 1 TOF (MET); 2polarised neutron instruments.*Instruments located at ECN PettenDates for proposal submission: no formal selectionprocessAddress for application forms:Dr. A.A. van Well, Interfacultair Reactor Institut, DelftUniversity of Technology, Mekelweg 15, 2629 JB Delft,The NetherlandsTel: +31 15 2784738; Fax: +31 15 2786422E-mail: [email protected]://www.iri.tudelft.nl

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FACILITIES

ISIS Didcot (UK)Type: Pulsed Spallation Source. Flux: 2.5 x 1016 n fast/sISIS operates at 200 µA in 0.4 µs pulsed at 50 HzNumber of instruments available to external users: 24Type of instruments available to external users: 3.5 powder diffractometers; 1 single crystaldiffractometer; 1 SANS; 2 reflectometers; 1 cold neutrontest VESTA; 1 single crystal alignment ALF; 5 muoninstruments; 1 neutrino facility; 1 3-axis spectrometers;1.5 quasielastic spectrometer; 4 TOF spectrometers; 1 eVspectrometer; 1 strain/pressure diffractometer.Dates for proposal submission: 16 April/16 OctoberDates for selection process: first week of June and Dec.Related scheduling periods: Sept-January/April-AugustAddress for application forms:ISIS Users Liaison Office, Building R3, RutherfordAppleton Laboratory, Chilton, Didcot, Oxon OX11 0QXTel: +44 (0) 1235 445592; Fax: +44 (0) 1235 445103E-mail: [email protected]://www.isis.rl.ac.ukJAERI (J)Japan Atomic Energy Research Institute, Tokai-mura, Naka-gun, Ibaraki-ken 319-11, Japan.Jun-ichi Suzuki (JAERI); Yuji Ito (ISSP, Univ. of Tokyo);fax: +81 292 82 59227 telex: JAERIJ24596http:// neutron-www.kekjpl

JEEP-II Kjeller (N)Type: D2O moderated 3.5% enriched UO2 fuel. Flux: 2 x1013 n/cm2/sNumber of instruments available to external users: 5Type of instruments available to external users: 2 powder/liquid diffractometers; 1 single crystaldiffractometer*; 1 SANS; 1 3-axis spectrometer*; 1quasielastic spectrometer (TOF).*The 3-axis instrument may be used as a single crystaldiffractometerDates for proposal submission: no special datesDates for selection process: no special datesAddress for application forms:Institutt for Energiteknikk K.H. Bendiksen, ManagingDirector, Box 40, 2007 Kjeller, NorwayTel: +47 63 806000, 806275; Fax: +47 63 816356E-mail: [email protected]://www.ife.no

LLB Orphée Saclay (F)Type: Reactor. Flux: 3.0 x 1014 n/cm2/sNumber of instruments available to external users: 24Type of instruments available to external users: 6 powder/liquid diffractometers; 2 single crystaldiffractometers; 1 Strain diffractometer; 1 Texturediffractometer; 3 SANS; 3 reflectometers; 5 3-axisspectrometers; 1 TOF (MET); 1 spin echo; 1 polarisedneutron instrument.Dates for proposal submission: SeptemberDates for selection process: NovemberRelated scheduling periods: January-DecemberAddress for application forms:Mrs Claude Rousse, Laboratoire Léon Brillouin, CEA-Saclay, 91191Gif-sur-Yvette Cedex, FranceTel: +33 1 6908 5241/5417; Fax: +33 1 6908 8261E-mail: [email protected]://www-drn.cea.fr

NFL Studsvik (S)Type: 50 MW reactor. Flux: > 1014 n/cm2/sNumber of instruments available to external users: 5Type of instruments available to external users: 1 powder diffractometer; 1 liquid diffractometer; 1single crystal diffractometer; 1 residual stressdiffractometer; 1 TOF (MET).Dates for proposal submission: 1 December, 1 April, 1August (for LSF programme only)Dates for selection process: Decisions before 1 January, 1May, 1 September (LSF only)Related scheduling periods: January-April/May-August/September-December.Address for application forms:Dr. R. McGreevy, NFL Studsvik, S-611 82 Nyköping,SwedenTel: +46 155 221000; Fax: +46 155 263070/263001E-mail: [email protected]://www.studsvik.uu.se

NISTNational Institute of Standards and Technology-Gaithersburg, Maryland 20899 USAC.J. Glinka; tel: + 301 975 6242 fax: +1 301 921 9847E-mail: Bitnet: GLINKA@NBSENTHInternet: [email protected]://rrdjazz.nist.gov

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FACILITIES

NPI Rez (CZ)Type: 10 MW research reactor.Address for informations:Zdenek Kriz, Scientif Secretary, Nuclear ResearchInstitute Rez plc, 250 68 Rez, Czech RepublicTel: +420 2 20941177 / 66173428; Fax: +420 2 20941155E-mail: [email protected] / [email protected]://www.nri.cz

ORNL (USA)Oak Ridge National Laboratory Neutron ScatteringFacilities, P.O. Box 2008, Oak Ridge TN 37831-6393 USAGeorge D. Wignall, Small Angle Scattering GroupLeaderTel: +1 423 574 5237; Fax: +1 423 574 6268E-mail: [email protected]://neutrons.ornl.gov

PSI-SINQ Villigen (CH)Type: Steady spallation source. Flux: 2.0 x 1014 n/cm2/sNumber of instruments available to external users: 10Type of instruments available to external users: 2 powder diffractometers; 1 single crystaldiffractometer; 1 SANS; 1 reflectometer; 2 3-axisspectrometers (one for polarised neutrons); 1 TOF (coldneutrons); radiography; prompt gamma analysis.Related scheduling periods: January-June/July-December.Address for application forms:Prof. Albert Furrer, Secretariat, Laboratory for NeutronScattering, ETH Zurich and Paul Scherrer Institute, CH-5232 Villigen PSI, SwitzerlandTel: +41 56 3102088; Fax: +41 56 3102939E-mail: [email protected]://lns.web.psi.ch

TU Munich FRM, FRM-2 (D)Type: Compact 20 MW reactor. Flux: 8 x 1014 n/cm2/sNumber of instruments available to external users: 14Type of instruments available to external users: 1 powder diffractometer; 1 soft phase boundarydiffractometer; 2 single crystal diffractometers; 2 singlecrystal spectrometers; 1 small angle spectrometer/diffractometer; 2 spin echo spectrometers; 2 3-axisspectrometers; 1 radiography-tomography; 2 TOFspectrometers.Address for informations:Prof. Winfried Petry, FRM-II Lichtenbergstrasse 1, 85747GarchingTel: 089 289 14701; Fax: 089 289 14666E-mail: [email protected]://www.frm2.tu-muenchen.de

NOTIZIARIO Neutroni e Luce di Sincrotrone - Issue 7 n.2, 2002

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Transcript of NOTIZIARIO Neutroni e Luce di Sincrotrone - Issue 7 n.2, 2002