PANAREAIMAT

F. AliottaIPCF-CNR, Messina, ITALY

ISIS is actually the world’s leading pulsed neutron and muon source.It is a high flux pulsed source (~1012 n∙cm-2·s-1). The time width of the moderated neutron pulse at the beginning of its path toward the sample is ~20 ms and the pulse repetition rate is 60Hz.The time width of the pulse on the sample depends on the length of the path to the sample area (after tenths of meters the pulse width becomes several hundreds s).

With the project TS2, in July 2003 began the construction of a second target station at ISIS.On 3 August 2008, the first neutrons from the new target station have been measured.The ISIS second target station project was completed in 2009. All seven Phase One neutron instruments are operational.

Since 1985, CNR has been supporting the access of italian researchers to the neutron spectroscopy techniques here available.

CNR-CCLRC International Agreement for the utilization of the ISIS spallation neutron source in the Rutherford Appleton Laboratory.(CCLRC=Council for the Central Laboratory of the Research Council)

Diamond

ISIS

Harwell Science & Innovation Campus

TS-II: 7 instruments10 HzTarget: W, clad in Ta

( 6.6, 27 cm)48 kW40 μA (60 μA)

TS-I20 instruments50 HzTarget: W, clad in Ta150 kW160 μA (240 μA)

Proton energy 800 MeV

With the project TS2, in July 2003 began the construction of a second target station at ISIS.On 3 August 2008, the first neutrons from the new target station have been measured.

In 2008 a new agreement for collaboration between CNR and STCF has been performed. Within this agreement a new project, PANAREA, will be developed, that will be co-financed by CNR and STCF (2008-2016).(STFC=Science and Technology Facilities Council)

The ISIS second target station project was completed in 2009. All seven Phase One neutron instruments are operational.

Since 1985, CNR has been supporting the access of italian researchers to the neutron spectroscopy techniques here available.

CNR-CCLRC International Agreement for the utilization of the ISIS spallation neutron source in the Rutherford Appleton Laboratory.(CCLRC=Council for the Central Laboratory of the Research Council)

Progetto per l'Applicazione dei Neutroni Alla

Ricerca in Elettronica e Archeometria

Agreement concerning collaboration in scientific research at the spallation neutron source ISIS

[...] CNR shall collaborate with CCLRC in the exploitation of ISIS by making contributions as follows: [...]Aiming to collaborate with CCLRC in the development of mutually beneficial instrumentation and techniques associated with the utilisation of ISIS Target Station 1 and especially its new Target Station 2.

CHIPIRCHIP IRradiation

IMATIMage and MATerials

science and engineering

A thermal-cold imaging / materials science beamline for TS-II

Imaging mode diffraction mode

IMAT will be a world-leading pulsed-source cold neutron radiography station and facility for materials science, materials processing and engineering.

CHIPIRCHIP IRradiation

IMATIMage and MATerials

science and engineering

IMAT

The possibility of non-destructive testing and the penetration power of neutrons is the basis of a materials science instrument for engineering, geology, and archaeological sciences. Imat will allow the study of novel alloys and composite materials, phase transformations, creeps and fatigue, corrosion, and ancient fabrication techniques.

Available Techniques:•Neutron radiography and tomography•Diffraction-enhanced imaging•Neutron strain scanning•Rapide texture analysis

Applications:•Aerospace and transportation•Fuel and fluid cell technology•Cultural heritage•Earth sciences•Engineerig and reverse engineering

IMATdiffraction mode

IMAT will be significantly complementary to ENGIN-X (TS1) which is specifically designed for evaluating lattice spacings in engineering relevant materials in minimum times.IMAT will employ a relaxed resolution to bias towards higher intensity, and will provide greater solid angle detector coverage in order to evaluate texture, phase volume fractions, and strain orientation distributions in short data acquisition times. The simultaneous analysis of internal stress and texture will be a unique and key capability of thebeamline.

Texture analysis capabilities are already available at the GEM and POLARIS instruments on ISIS TS1.IMAT will have a highly flexible and spacious sample area to accommodate a diverse range of engineering-specific and user-supplied sample environment and processing cells and allow for motorised spatial scanning.

POLARIS

GEM

The instrument will be ideally suited to in-situ processing studies, in which materials are typically peak-broadened so that instrumental resolution is not a critical parameter.

Bragg edge analysis allows to obtain information about the stress and deformation distribution in mechanical components.

The fine selection of the neutron energy allows to evidenciate any small local deformation of the crystaline lattice.

Energy resolved imaging would allow to clearly distinguish among different materials.

To tune the neutron energy around the Bragg edge of the material of interest results in the increasing of the phase contrast.

The otained image can be used to select the sample volume which must be investigated by diffraction technique.

imaging diffraction

target/moderator TS-II /broad-face, decoupled solid-CH4. (Alternative: TS-II /coupled LH2 for high intensity imaging).

TS-II /broad-face, decoupled solid-CH4.

wavelength range 1 - 7 Å (dmax at 180°: 3.5 Å l-Ni(100));

1 - 7 Å (dmax at 180°: 3.5 Å l-Ni(100));

incident collimation/focussing

adjustable apertures D=10-100 mm for varying L/D >300

motorised jaws, 0.1-20mm; ellipsoidal mirror for focussing

beam size/field of view maximum 20x20 cm2 variable (max horizontal/vertical: 8/20mm)

flight path moderator-pinhole

10 m 10 m

flight path pinhole sample

~25 m ~25 m

spatial resolution better than 0.2x0.2 mm standard operating mode: 5x5x5 mm3, variable from 1-10mm

d-spacing resolution n/a Δd/d: 0.3 % at 2θ=90°

outgoing beam collimation

n/a standard mode 5 mm, removable radial 90° collimators for variable resolution

divergence L/D: > 300 (< 0.2° vertical and horizontal)

0.35° horizontally; vertically larger; tunable

IMAT: instrument parameters

Common features of IMAT for the two operating modes are a Bragg edge detector, the sample positioning systems and the sample environment. Switching IMAT from imaging to diffraction mode must not require sample removing. This will allow a complete survey of a sample by 2D or 3D imaging, followed by a detailed diffraction analysis of the interesting regions guided by the tomography data.

simulated intensity distribution

image mode diffraction mode

An ellipsoidal mirror will allow switching between image mode and diffraction mode with a collimated neutron beam. The neutron focusing device is curved in two dimensions, with a length of about 10 m and a height of about 10 cm.

Inter

LetNimrod

Offspec

Polref

Wish

IMAT

IMAT drawings

IMAT moderator

Material LH2, 22K

Solid-methane, 26 K

De-coupler none

Poison none

W5 size 110 mm high

IMAT

ZOOMCHIPIR

LAMOR

IMAT on W5

TS-II phase 2

Source repetition 10 Hz

Moderator Liquid H2 / solid CH4 coupled

Primary neutron guide m=3 straight, square, 95x95 mm

Single frame bandwidth 0.5 - 6.5 Ǻ

Flight path to sample 56 m

Disc chopper 1: 10 HzPosition: 12.8 m

T0-chopper: 20 HzPosition: 21.1 m

Disc chopper 2: 10 HzPosition: 21.5 m

Aperture selectorD = 10 , 20 , 40 , 75 mm + openL/D = 1000, 500, 250, 133

LET

IMAT

Incident beamline

IMAT blockhouse

Day-1 90-degree detectors

Imaging cameras

Pinholeselector

sample

• Large detector coverage for rapid phase and texture analysis

• Scintillation detectors; fibre-coded or wavelength shifting fibres

• Highly pixellated; each pixel <5deg

• Medium spectral resolution for strain analysis

Primary flight path 56 m

L: pinhole-detector 10 m

D: pinhole sizes 10, 20, 40, 75 mm

L/D 1000, 500, 250, 133

Spatial resolution Standard: 200 micron

Minimum: 100 micron

Wavelength resolution 0.7 % at 3Å

Neutron flux (L/D=250) 2 ·107 neutrons·cm-2·s-1

Max. field of view 200 x 200 cm2

IMAT ENGIN-X

diffraction resolution(3Å/90º)

0.69 % 0.33 %

strain resolution[microstrain]

70 50

Bragg intensity 3 Å [a.u.] 8.5 1.0

Strain analysis performance

1.8 1.9 2.0 2.1 2.2 2.3

0

200000

400000

inte

nsi

ty

d-spacing (Angstrom)

E8: de-coupled CH4 W5: coupled H2

Neutron Flux Gain over ENGIN-X

Primary flight path 56 m

L: pinhole-detector 10 m

D: pinhole sizes 10, 20, 40, 75 mm

L/D 1000, 500, 250, 133

Spatial resolution Standard: 200 micron

Minimum: 100 micron

Wavelength resolution 0.7 % at 3Å

Neutron flux (L/D=250) 2 ·107 neutrons·cm-2·s-1

Max. field of view 200 x 200 cm2

• High flux moderator

• Energy resolution better than 0.8%

• Two imaging positions

• Gated CCD + Bragg edge transmission detectors

First questions: are we able to get conventional tomography images from the beam flux available at the ISIS pulsed source?

are we able to obtain the required spatial resolution performances?

First prototype (installed at INES)

•Flight Path L = 23.84 m•Source Dimension D ~ 8.5 cm => L / D ~ 280•Sample-scintillator distance l ~ 10 cm (Mean) •Spatial Resolution: 0.26 < d < 0.42 [mm]•Camera CCD not cooled 640x480 - 8 bit•Optics 8 mm, f: 1.4•Scintillator ZnS / 6LiF on Al substrate

The Imaging Source: DMK 21BF04

Further questions: which kind of imaging device is more appropriate to obtain high spatial resolution images on the large field (20x20cm2) that will be available at IMAT?

is it possible to obtain the required time resolution by any commercial imaging device?

are there practical perspectives to reach an enough high efficiency of energy selective image acquisition?

which kind of scintillator plate can ensure us a bright image together with the required space and time resolution performances?

which is the better geometry to minimize radiation damages effects of the CCD (or any other imaging device)?

Second prototype (portable test chamber)

Scintillator plateMirrorRotating platformX-Z translatorCCD

•Flight Path L = variable•Source Dimension D variable•Sample-scintillator distance 8 cm l 30 cm•Spatial Resolution: variable•Camera CCD inter-changeable•Optics 35÷135 mm, f: 4.5÷5.6•Scintillator variable

Test at ROTAXsample: nail from a medieval wreck found in the Palermo Gulf.

CCD: Andor iStar DH712scintillator plate: ZnS(Ag)6Li

Tests at ROTAX CCD: Andor iStar DH712

scintillator plate: ZnS(Ag)6Li

Sample 1: fibula Sample 2: snail

Effective active area of CCD 13.3x13.3 mm2

Fibre optic taper magnification

1:1

Effective CCD pixel size 13x13 m

(100% fill factor)

Active pixels 1024X1024

Read noise As low as 2.9e

Frame rate (image/sec max,) 0.9

Useful photocatode spectral range

120 – 1090 nm

Photocatode QE Up to 50%

Minimum optical gate width 1.2 ns

Specification Summary

Andor iStar 734

200 300 400 500 600 700 800

200

250

300

350

400

450

Res

olut

ion

[m

]

Thickness [m]

Experimental Linear Fit of B

Equation y = a +

Adj. R-Sq 0.9243

Value Standard

B Interce 169.89 15.9944

B Slope 0.3241 0.04112

Slanted Edge Method

Line Spread Function

Point Spread Function

At TS2 the distance between pulses is 20 ms.

The acquisition of energy resolved images with enough energy resolution to distinguish the Bragg edge shift originated by local deformation of a material implies a time resolution of 10 s.

20000 images are required to cover the 20ms interval between pulses with 10 s aquisitions.

At IMAT: the neutron beam section will be 20x20cm2;

the estimated neutron flux is about 2∙107 neutron/s.

With a 1024x1024 pixel detector, the average counting rate on each pixel will be of 0.95 over 10s.

On day 1, recording an image at a single energy value will require an acquisition time of about 30s.

G.Salvato, F. Aliotta, V. Finocchiaro, D. Tresoldi, C.S.Vasi, R.C. PonterioNuclear Instruments and methods in physics research, A 621, 489, 2010.

type thickness

N1 6LiF/ZnS:Ag 225 m

N2 6LiF/ZnS:Cu 225 m

N3 6LiF/ZnS:Ag 450 m

14.3ms –0.5ms

Cu

Fe

15.5ms – 0.5ms

Cu

Fe

available room: 400x660x900 mm3

requirements: 2048x2048 CCD ready, user friendly

OPTICS

lens: NIKON 85mm f/1.4 mirrors: silicon wafer (Al coated)

Newport

Edmund Optics

Reactors

1. FRM-II Garching, GERMANY (fast neutrons, 8∙1014 n·cm-2∙s-1) 2. BENSC (CONRAD) Berlin, GERMANY (cold neutrons, 109 n·cm-2∙s-1)3. CASACCIA Rome, ITALY (thermal neutrons, 2∙106 n·cm-2∙s-1)4. CEA Saclay, FRANCE (thermal neutrons, 3.4∙106 n·cm-2∙s-1)5. ATOMINSTITUT Wien, AUSTRIA (thermal neutrons, 1.3∙105 n·cm-2∙s-1)6. KFKI Budapest, HUNGARY (thermal neutrons, 108 n·cm-2∙s-

1)Neutron Spallation Sources

1. SINQ (NEUTRA, PGA) Villigen, Switzerland (thermal and cold neutrons, 1014 n·cm-2∙s-1,

continuous)2. LPI Moscow, Russia

(thermal and fast neutrons, 109 n·cm-2∙s-1, pulsed)

NEUTRON TOMOGRAPHY IN EUROPE