Energy-resolved neutron imaging with MCP/Medipxtechnology

120th Anniversary symposium on Medipix and Timepix, CERN, September 18, 2019

Energy-resolved neutron imagingwith MCP/Medipx technology

Energy-resolved neutron imagingwith MCP/Medipx technology

A.S. Tremsin , J.V. Vallerga

Space Sciences LaboratoryUniversity of California at Berkeley, USA


14 mm

Unique capabilities of neutron imaging


X-rays versus neutrons

X-rays interact with electrons in the atoms.The heavier is the atom – the larger is absorption of X-rays.

Neutrons interact with nucleus and have very different absorption contrast.

NIST annual report 2003, D. Jacobson, M. Arif, and P. HuffmanPhysics Laboratory Ionizing Radiation Division


14 mm

New detector technology we use in neutron imaging was partially

developed for astrophysical applications:

• Event counting• UV, soft X-ray sensitive• High dynamic range• Low noise/background• Good spatial resolution


Detectors developed at Berkeley for NASA applications

MCP detector technology developed for astrophysical

applications

NASA Image satellite


14 mm

Mdipix/Timepix neutron imaging was pioneered byInstitute of Experimental and Applied Physics,

Czech Technical University in Prague


MCP electron amplifier for UV/neutron detection

Circular pores ~8 m

V1

V2

Single pore

1 mm absorption

length

Walls between pores ~2 m

10B and Gddoping in glass

n

7Li

4He

1 mm absorption length~2 m escape range

High detection efficiency


64 data lines@100 MHz

MCPs

Timepixreadout

FPGA

64 data lines@100 MHz

FPGA

PCPC10 Gb interface10 Gb interface

~1.8 Mb/frame, up to 1200 frames/s

~1.8 Mb/frame, up to 1200 frames/s

Up to ~6 Gb/s

Vacuum ~10-6

Torr

• Bright pulsed neutron beams

• New neutron counting detectors with high timing and spatial resolution @ high count rates

Enabling technology: MCP/Timepix detectors

Active area with 2x2 Timepixchips (28x28 mm2)

Fast parallel readout (x32) allowing ~1200 frames per second and ~300 s dead time

Wide transmission spectrum measured at the same time.

A.S. Tremsin, et al., NIM A 787 (2015) 20–25.


Neutron cross sections vs. energyThermal range

1-5 Å (~4-100meV)

Bragg edges

Epithermal range1eV-10 keV (~2-300 mÅ)

Resonance attenuation

Crystallographic parameters extractedPhase

Texture Lattice parameter

Elemental/isotopic compositionTemperature map

1.0E+01

1.0E+02

1.0E+03

1.0E+04

1 10 100C

ross

sec

tion

(bar

ns)

Neutron energy (eV)

Eu-153


From radiography to energy resolved imaging

Images are taken from google images website


All energies are imagedat the same time!

Propagating neutron pulse

Neutron counting2D detector

Time

X

Y

Trigger synchronized to the source

X,Y,T for every detected neutron

Pulsed Neutron Source20 - 60 Hz

~100 ns pulses

Sample

~250,000 spectra is measured simultaneously!

Energy-resolved neutron imaging: time of flight

0.30.350.4

0.450.5

0.550.6

0.65

1 2 3 4 5

Tran

smis

sion

Wavelength (Å)

N2N1Annealed

200311 220 111


Application examples.

Optimization of crystal growth: In-situ imaging


Slide by Prof. J.J Derby, Univ. Minnesota


Industrial Bridgman furnace: RMD

A two-zone furnace, which allows 2” growth. Theoretically it can be used in neutron imaging experiments,

although our 5-zone furnace is better suited for it.Proc. of SPIE Vol. 8507 850716-1,

Hard X-Ray, Gamma-Ray, and Neutron Detector Physics XIV


Understand and optimize growth process for single crystal materials.

Transfer that knowledge to industrial scale production.

Crystal growth: In-situ measurement

Dedicated furnaces optimized for neutron imaging were developed.


Experimental setup pulsed beam: energy resoled imaging

Map of Euconcentration

~250000 spectra are measured

at the same time, each within 55 um pixel!

A.S. Tremsin, et al., Scientific Reports 7 (2017) 46275

1720th Anniversary symposium on Medipix and Timepix, CERN, September 18, 2019Jeff Derby, Univ. Minnesota


Crystal growth – in situ diagnosticsInitially 1 mm/hr pull speed. Increased to 2 mm/hr. Strong asymmetry of interface seen at high speed.

20 min image acquisition per step

1. Interface is convex, as desired.2. Interface remains at the same position/moves slowly during regular growth.

Should allow real-time adjustment of T profile to keep the interface convex and at the desired location.


Controlled interface shape

Sample width ~11 mm

Interface between the liquidand solid phases is convex.Contrast is due to segregation of Eu (CsI:Eu)and Li (in TLYC) between the liquid and solidphases.

Booster heater area. Neutron scattering distorts the image.

(CsI:0.5%Eu)Tl2LiYCl6:Ce


In-situ Eu distribution quantification

00.10.20.30.40.50.60.70.80.91

0.01 0.1 1 10

Tran

smission

Neutron enery (eV)

Solid 5% Solid 0.5% Melt 5%Theory 5.5% Theory 0.4% Theory 4%

Eu concentration (mole %)

00.10.20.30.40.50.60.70.80.91

0 5 10 15 20

Eu con

centratio

n (m

ole %)

Position (mm)

0.5% Eu

Started growth

Solid/liquid interface

0123456789

10

0 5 10 15 20

Eu con

centratio

n (m

ole %)

Position (mm)

5% EuStarted growth

Solid/liquid interface 0

123456789

10

0 2 4 6 8 10 12Eu

con

centratio

n (m

ole %)

Position (mm)

Solid phaseLiquid phase

5 mole % Eu doping

Vertical profiles

Radial profiles

Scientific Reports 7 (2017) 46275


In-situ measurement of strain


Load in Spiralock threads: vibrational stability

Steel screws in Al base

Steel screws in stainless steel

A.S. Tremsin, et al., Strain 52 (2016) 548-558


Torqued to 185 lb-in Not torqued

-1000

-800

-600

-400

-200

0

200

400

0 5 10 15 20 25 30

Mic

rost

rain

µε

Distance Along Bolt mm

RegularSpiralock

Thread start

Loaded Steel

-1000

-800

-600

-400

-200

0

200

400

0 5 10 15 20 25 30

Mic

rost

rain

µε

Distance Along Bolt mm

RegularSpiralock

Thread start

Unloaded Steel

A.S. Tremsin, et al., Strain 52 (2016) 548-558

Load in Spiralock threads: vibrational stability


Larger contiguous MxN area (TSVs)Better timing resolution Huge dynamic rangePhoton/particle counting

Future capabilities enabled by Timepix4

28x28 mm (2x2 Timepix)

200x200 mm (7x7 Timepix4)

Hubble Space

Telescope2.4 m(1990)

James WebbSpace

Telescope6.5 m

(~2021)

LUVOIR 16 m!!(~2035)


CERN Medipix teamAdvacamNIKHEF, Amsterdam IEAP, PragueUniversity of California at Berkeley, CA, USA

A.S. Tremsin, J. B. McPhate, J. V. Vallerga, O. H. W. SiegmundNova Scientific, Inc, Sturbridge, USA (manufacturer of neutron sensitive MCPs)

W. B. Feller, P. White, B. WhiteRutherford Appleton Laboratory, ISIS Facility, UK

W. Kockelmann, J. Kelleher, S. Kabra, D.E. Pooley, G. Burca, T. Minniti, E. Schooneveld, N. RhodesJ-PARC Center, JAEA, Nagoya University, Japan

Y. Kiyanagi, T. Shinohara. T. Kai, K. OikawaLANSCE, Los Alamos National Laboratory Lawrence Berkeley Laboratory

S. Vogel, A. Losko, M. Mocko, M.A.M. Bourke, R. Nelson D. Perrodin, G.A. Bizarri, E.D. BourretPaul Scherrer Institute, Switzerland

E. Lehmann, A. Kaestner, T. Panzner, P. Trtik, M. ManganoIstituto dei Sistemi Complessi, Sesto Fiorentino (FI), Italy European Spallation Source Scandinavia

F. Grazzi M. Strobl, R. WoracekANSTO Technical University of Denmark

A. Sokolova, A. Paradowska, V. Luzin, F. Salvemini S. SchmidtCONICET and Instituto Balseiro, Centro Atomico Bariloche, Argentina

J. SantistebanSpallation Neutron Source, Oak Ridge National Laboratory, USA Open University, Coventry University, UK

H. Z. Bilheux, L.J. Santodonato M. Fitzpatrick, R. RamadhanTechnische Universität München, Forschungs-Neutronenquelle FRM-II, Germany

B. Schillinger, M. LercheDepartment of Geology and Environmental Earth Science, Miami University

John RakovanWelding Science, Cranfield University General Electric Global Research

Supriyo Ganguly Yan GaoUniversity of Newcastle, Latrobe University, Australia

C. Wensrich, E. Kisi. H. Kirkwood

The work done in collaboration

…and many others!apologies for missed names


Thank you for your attention! This work was done within the Medipix collaboration.

We would like to thank Medipix collaboration for the readout electronics and data acquisition software (Advacam, Prague and Espoo, NIKHEF, Amsterdam and IEAP, Prague).

This work was supported in part by U.S. agencies: NASA, DOE, NSF, NIH and NNSA.

Energy-resolved neutron imaging with MCP/Medipxtechnology

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