RFQ Posters at EPAC2002, Paris

Alan Letchford, ISIS Accelerator Division, Linac Group

A summary of Radio Frequency Quadrupole

accelerator work as presented at the

poster sessions of the 8th European Particle

Accelerator Conference, Cité des Sciences, Paris, June

2002.

What is an RFQ accelerator?

The principles of operation of the RFQ where first presented by two scientists from ITEP Moscow in the former Soviet Union (now Russia)

I.M. Kapchinsky & V.A. TeplyakovLinear ion acceleration with spatially homogeneous strong focussingPrib. Tekh. Eksp. No.2 pp19-22 (1970)

First practical RFQ was realised by LANL (then LASL) in 1980. Much development occurred around this time in the USA driven by SDI (Star Wars)

The Quadrupole Lens

+

-

+

-

N S

NS

Magnetic Quadrupole Lens

Electric Quadrupole Lens

Focusing in one plane, de-focusing in the other

Alternating Gradient Focusing

F D F D F

D F D F D

Net focusing can be achieved by a system of focusing and defocusing elements

Radio Frequency Quadrupole

F F

F F

F

D D D F

D D D

Why an RFQ?

Magnetic quadrupoleforce:

Fx = -q B0 x aFy = +q B0 y a

Electric quadrupoleforce:

Fx = -qV0 x a2

Fy = +qV0 y a2

Ek = 35 keV = 0.0086 cRequired pole tip field fora = 5 mm, B0 = 3.5T

E.g. ISIS RFQ input:

V0 = 45 kV, a = 5 mm

Very high!

RFQ with acceleration

Vertical electrodes

Horizontal electrodes

3D focusing and accelerating field

Vertical electrode

Horizontal electrodeQuadrupole focusing field

Axial acceleration field

RFQ accelerator

Vertical force

Horizontal force

Axial force (acceleration)

ISIS RFQ structure

Electrode support assembly

ISIS RFQ structure

Electrode support assembly with electrodes

ISIS RFQ structure

Electrode detail

ISIS RFQ structure

Electrode detail

ISIS RFQ structure

Vacuum vessel and RF feed loop

Completed ISIS RFQ

ISIS EHT area, LEDS and RFQ test stand

RFQ posters at EPAC2002www.cern.ch/EPAC

34 Posters with RFQ keyword

Superconducting RFQ's Ready for Ion Beam Operation at INFN-Legnaro G. Bisoffi, V. Andreev, G. Bassato, G.P. Bezzon, S. Canella, F. Chiurlotto, A. Lombardi, A.M. Porcellato, INFN-LNL, Legnaro, Padova; E. Chiaveri, CERN, Geneva; W. Singer, DESY, Hamburg; T. Shirai, ICR, Kyoto; S.Y. Stark, Strumenti Scientifici, CINEL,

Vigonza, Padova Status Report on the Construction of the French High Intensity Proton Injector (IPHI) P.-Y. Beauvais, CEA, Gif-sur-Yvette

Correction of Spherical Aberrations by a Partially Neutralized Beam Part for the

Injection of Ions into a RFQ R. Becker, IAP, Frankfurt-am-Main; M. Mücke, Singulus Technologies GmbH, Alzenau

Linac Complex in the JAERI-KEK Joint RNB Facility S. Arai, Y. Arakaki, K. Niki, M. Okada, Y. Takeda, M. Tomizawa, KEK, Ibaraki-ken; S. Takeuchi, JAERI, Ibaraki-ken

Results from the ISIS RFQ Test Stand C.P. Bailey, J.P. Duke, A.P. Letchford, J.W.G. Thomason, CLRC RAL, Chilton, Didcot

Exploring the Feasibility of a Separated Function RFQ Structure C.E. Chen, J.X. Fang, Z.Y. Guo, W.G. Li, X.Q. Yan, IHIP, Beijing; Y. Wu, IPP, Hefei

Design of a 200MHz Proton RFQ Z.Y. Guo, C.E. Chen, J.X. Fang, Y.R. Lu, X.Q. Yan, C. Zhang, IHIP, Beijing

Injection into RFQ Using Beams with Different Energies V. Kapin, K. Noda, NIRS, Chiba City

New Potential Function for RFQ Accelerator Cells S. Koscielniak, TRIUMF, Vancouver

Development of a FDT-Cavity K.-U. Kuehnel, A. Schempp, IAP, Frankfurt-am-Main

RFQ posters at EPAC2002 Field Tuning of the TRASCO RFQ G. Lamanna, INFN-Bari, Bari; S. Fu, H.F. Ouyang, IHEP, Beijing; A. Palmieri, A. Pisent, INFN-LNL, Legnaro, Padova

Measured Performance of the ISIS RFQ A.P. Letchford, C.P. Bailey, J.P. Duke, D.J.S. Findlay, J.W.G. Thomason, CLRC RAL, Chilton, Didcot

Electromagnetic Design of an 80.5 MHz RFQ for the RIA Driver Linac H. Podlech, U. Ratzinger, IAP, Frankfurt-am-Main; D. Gorelov, W. Hartung, F. Marti, X. Wu, R.C. York, NSCL, East Lansing

RIA RFQ Beam Dynamic Studies H. Podlech, U. Ratzinger, IAP, Frankfurt-am-Main; D. Gorelov, W. Hartung, F. Marti, X. Wu, R.C. York, NSCL, East Lansing

Design of a 40 MHz RFQ for a Post Accelerator at the Coupled Cyclotron Facility at

NSCL H. Podlech, IAP, Frankfurt-am-Main; D. Gorelov, W. Hartung, F. Marti, X. Wu, R.C. York, NSCL, East Lansing

Theoretical Analysis of a Real-life RFQ Using a 4-Wire Line Model and the Theory of

Differential Operators F. Simoens, A. France, CEA, Gif-sur-Yvette

A New RFQ Model Applied to the Estimation of Mechanical Defaults Distribution F. Simoens, A. France, J. Gaiffier, CEA, Gif-sur-Yvette

A Fully Automated Test Bench for the Measurement of the Field Distribution in RFQ

and Other Resonant Cavity F. Simoens, F. Ballester, A. France, J. Gaiffier, A. Sinanna, CEA, Gif-sur-Yvette

Funneling with the Two-beam RFQ H. Zimmermann, A. Bechtold, A. Schempp, J. Thibus, IAP, Frankfurt-am-Main

Commissioning of the SNS Front-End Systems at Berkeley Lab R. Keller, J.J. Ayers, L. Doolittle, J.B. Greer, S. Lewis, C. Lionberger, M. Monroy, J. Pruyn, A. Ratti, J.W. Staples, D. Syversrud, R.W. Thomae, LBNL, Berkeley; A. Aleksandrov, T. Shea, ORNL, Oak Ridge

Ion Beam Buffer Gas Cooling by a RF-Quadrupole E. Vassilakis, A. Schempp, IAP, Frankfurt-am-Main

RFQ posters at EPAC2002 Electromagnetic Characterization of the First IPHI RFQ Section F. Simoens, A. France, J. Gaiffier, CEA, Gif-sur-Yvette

Beams Dynamics End to End Simulations in IFMIF Linac R. Duperrier, R. Ferdinand, N. Pichoff, D. Uriot, CEA, Gif-sur-Yvette

A New Experimental Approach to Space Charge Effects H. Okamoto, K. Ito, R. Takai, Y. Wada, Hiroshima University, Higashi-Hiroshima

Synchrobetatron Dynamics with a Radio Frequency Quadrupole A.A. Valishev, E.A. Perevedentsev, BINP, Novosibirsk

BRICTEST: A Code for Charge Breeding Simulations V. Variale, INFN-Bari, Bari; M. Claudione, T. Clauser, A. Raino', Universita' di Bari e INFN-Bari, Bari

The RFQ Test Stand Ion Source at RAL J.W.G. Thomason, P.J.S. Barratt, C.J. Barton, J.C. Kerr, C.R. Lambourne, A.P. Letchford, G.R. Murdoch, M. Perkins, J. Saunders, R. Sidlow, C.P. Viswanathan, M.O. Whitehead, CLRC RAL, Chilton, Didcot

Measurements of Beam Energy using the Gas Scattering System in the ISIS RFQ Test Stand J.P. Duke, D.J.S. Findlay, S. Hughes, P. Knight, G.R. Murdoch, CLRC RAL, Chilton, Didcot

A New Structure combining Low Dimensions of the Four Rods and Technical Advantages of the Four Vanes M. Painchault, R. Duperrier, CEA, Gif-sur-Yvette

High Power RF System for KOMAC RFQ Y.-S. Cho, B.-H. Choi, J.-M. Han, H.-J. Kwon, KAERI, Daejon

Status of the Vacuum System for the IPHI Project N. Rouvière, F. Dubois, R. Leplat, L. Vatrinet, IPN, Orsay; R. Gobin, F. Harrault, P.A. Leroy, CEA, Gif-sur-Yvette

Design and Construction of an RFQ-Drifttube-Combination for a Medicine Synchrotron A. Bechtold, U. Ratzinger, A. Schempp, IAP, Frankfurt-am-Main; B. Schlitt, GSI, Darmstadt

Development and Construction of Experimental ADS at ITEP A.M. Kozodaev, N.D. Gavrilin, V.N. Konev, N.V. Lazarev, D.A. Liakin, A.M. Raskopin, B.Yu. Sharkov, O.V. Shvedov, E.B. Volkov, ITEP, Moscow

COMMISSIONING OF THE SNS FRONT-END SYSTEMS AT BERKELEY LAB

R. Keller, J.J. Ayers, L. Doolittle, J.B. Greer, S. Lewis, C. Lionberger, M. Monroy, J. Pruyn, A. Ratti, J.W. Staples, D. Syversrud, and R. Thomae

Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA, USAA. Aleksandrov for the SNS Accelerator Physics Group and T. Shea for the SNS Diagnostics

Collaboration

AbstractConstruction of a 2.5-MeV linac injector, the Front-End (FE) for the Spallation Neutron Source (SNS) project, was completed in the spring of 2002. Of the major FE subsystems, the rf-driven H- ion source, the electrostatic LEBT, and the first of four RFQ modules had been commissioned by the spring of 2001, and commissioning of the remaining RFQ modules as well as the full system including the elaborate MEBT was carried out in Jan. through May, 2002. The Front End will be shipped to Oak Ridge, starting in June, 2002, and re-commissioned after installation at the SNS site. This paper gives an overview of FE major design features and experimental results obtained during the commissioning process at LBNL.

COMMISSIONING OF THE SNS FRONT-END SYSTEMS AT BERKELEY LAB

STATUS REPORT ON THE CONSTRUCTION OF THE FRENCH HIGH INTENSITY PROTON

INJECTOR (IPHI). P-Y Beauvais for the CEA and CNRS IPHI team, CEA Saclay, DSM/DAPNIA 91191 Gif sur Yvette

Cedex Abstract In 1997, the two French National Research Agencies (CEA and CNRS) decided to collaborate in order to study and construct a prototype of the low energy part of a High Power Proton Accelerator (HPPA). The main objective of this project (the IPHI project), is to allow the French team to master the complex technologies used and the control concepts of the HPPAs. The applications of such accelerators are numerous : Accelerator Driven Systems, irradiation tool, condensed matter studies, radioactive beam, muon or neutrino production. This demonstration linear accelerator, the assembly of which is presently in progress on the Saclay site, could reach in a final state a power of more than 1 MW for an energy of about 10 MeV (not presently funded). In a first step, the energy beam will be limited to 5 MeV. This paper reports on the state of the construction and assembly of IPHI. The planning of assembly and starting is also presented.

STATUS REPORT ON THE CONSTRUCTION OF THE FRENCH HIGH INTENSITY PROTON

INJECTOR (IPHI).

LINAC COMPLEX IN THE JAERI-KEK JOINT RNB FACILITY

S. Arai, Y. Arakaki, K. Niki, M. Okada, Y. Takeda, M. Tomizawa, KEK, Ibaraki-ken, Japan S. Takeuchi, JAERI, Ibaraki-ken, Japan

Abstract Construction of the JAERI-KEK joint RNB facility has started from 2001 at JAERI-Tokai tandem site. In the first stage, the facility comprises a tandem accelerator, an isotope-separator on line and a linac complex. The radioactive nuclear beams (RNBs) are produced by a 36-MeV 3-µA proton beam from tandem accelerator. The linac complex comprises a 26-MHz split coaxial RFQ and a 52-MHz interdigital-H (IH) linac. The beam energy is available in the range of 0.14 to 1.09 MeV/u. In the second stage, the RFQ/IH linac is connected to the JAERI superconducting tandem booster linac by adding a 2-MeV/u linac between them. The extended linac complex can provide the maximum beam energies of 5 Mev/u for q/A=1/7 ions and 8 MeV/u for q/A=1/4 ions.

LINAC COMPLEX IN THE JAERI-KEK JOINT RNB FACILITY

FUNNELING WITH THE TWO-BEAM RFQ

H. Zimmermann, A. Bechtold, A. Schempp, J. ThibusInstitut für Angewandte Physik, Johann Wolfgang Goethe-Universität,

Robert-Mayer-Straße 2-4, D-60325 Frankfurt am Main, GermanyAbstractNew high current accelerator facilities like proposed for ESS requires a beam with a very high brilliance. These beams can not be produced by a single ion-source. The increase in brightness in the driver linac is done by several funneling stages at low energies, in which two identically bunched ion beams are combined into a single beam with twice the frequency, current and brightness. Our Two-Beam-RFQ funneling experiment is a set-up of two ion sources, a Two-Beam-RFQ, two different funnel deflectors and beam diagnostic equipment to demonstrate funneling of ion beams as a model for the funneling stage for the ESS driver. The progress of the funneling experiment and results of simulations will be presented.

FUNNELING WITH THE TWO-BEAM RFQ

THE RFQ TEST STAND ION SOURCE AT RAL

J. W. G. Thomason, P. J. S. Barratt, C. J. Barton, J. C. Kerr, C. R. Lambourne, A. P. Letchford, G. R.Murdoch, M. Perkins, J. Saunders, R. Sidlow, C. P. Viswanathan and M. O. Whitehead, CLRC

RAL, Didcot, Oxon, UK

AbstractThe RFQ test stand at Rutherford Appleton Laboratory (RAL) is now being operated with an ion source identical to that used on ISIS. This is a surface plasma ion source of the Penning type, and on ISIS routinely produces 35mA of H- ions during a 200 µs pulse at 50 Hz for uninterrupted periods of up to 50 days. A new ion source vacuum chamber which is compatible with the low energy beam transport system for the RFQ has been constructed, and the layout of power supplies and other essential services have been reconfigured in order toensure that the RFQ will fit the space available when it is eventually installed on ISIS. An extensive redesign of many power supplies, where exact duplication of the ISIS equipment has proved impossible because of component obsolescence, has been necessary. In addition a new timing system and control systems using fibre optic ethernet have been developed specifically for this application.

THE RFQ TEST STAND ION SOURCE AT RAL

MEASUREMENTS OF BEAM ENERGY USING THE GAS SCATTERING

SYSTEM IN THE ISIS RFQ TEST STANDJ P Duke, D J S Findlay, S Hughes, P Knight, G R Murdoch, CLRC, RAL, Chilton, Didcot

AbstractThe new RFQ accelerator for the ISIS Spallation Neutron Source at the Rutherford Appleton Laboratory (RAL) is designed to accelerate H– particles from 35 keV to 665 keV. Beams have already been successfully accelerated through the RFQ, and now investigations are continuing into the detailed properties of the accelerated beam using the RFQ Test Stand at RAL. A novel system has been set up in which the beam of accelerated particles is attenuated in cascaded multiple scattering cells filled with xenon gas and the energies of the particles are measured using a semiconductor particle detector. Measurements and results are reported.

MEASUREMENTS OF BEAM ENERGY USING THE GAS SCATTERING

SYSTEM IN THE ISIS RFQ TEST STAND

MEASURED PERFORMANCE OF THE ISIS RFQ

A.P. Letchford, C.P. Bailey, J.P. Duke, D.J.S. Findlay, J.W.G. Thomason, CLRC RAL, Didcot, UK

AbstractThe ISIS RFQ is a 665 keV, 202.5 MHz, 4-rod RFQ intended as a replacement pre-injector for the ISIS spallation neutron source at RAL. A test facility has been constructed for soak testing and characterising of the RFQ before installation. Results are presented for measurements of the principal parameters of the RFQ together with its performance characteristics. A comparison is made between the measurements and the results from computer simulations.

MEASURED PERFORMANCE OF THE ISIS RFQ

MEASURED PERFORMANCE OF THE ISIS RFQ

LEBT Emittances

MEASURED PERFORMANCE OF THE ISIS RFQ

Measured

Calculated

Output Emittances

ElectrodeVoltage

Measured PeakEnergy

Calculated PeakEnergy

80 kV 661 keV 661 keV

85 kV 665 keV 663 keV

90 kV 670 keV 669 keV

Final Energy