Constructing and calibrating a neutron detector using cosmic rays
The µPIC-based neutron imaging detector (µNID) for energy ... · µPIC-based neutron imaging...
Transcript of The µPIC-based neutron imaging detector (µNID) for energy ... · µPIC-based neutron imaging...
The µPIC-based neutron imaging detector (µNID) for energy-resolved neutron imaging at J-PARCJoe Parker CROSS
�15�MPGD @ 14 December 2018
RADEN and µNID development members
JAEA/J-PARC Center Takenao Shinohara Tetsuya Kai Kenichi Oikawa (BL10) Masahide Harada (BL10) Takeshi Nakatani Mariko Sagawa Kosuke Hiroi Yuhua Su
CROSS Joe Parker (µNID Lead Developer)
Hirotoshi Hayashida Yoshihiro Matsumoto Nagoya University Yoshiaki Kiyanagi Kyoto University Toru Tanimori Atsushi Takada (µNID development) Taito Takemura Tomoyuki Taniguchi
Ken Onozaka Mitsuru Abe
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Outline
• (Brief) Intro to energy resolved neutron imaging
• Current status of the µNID at RADEN
• Ongoing development
• 215µm pitch MEMS µPIC
• µNID with boron converter
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Energy-resolved neutron imaging at RADEN
• Energy-dependence quantitative information on macroscopic distribution of microscopic quantities
• Pulsed neutrons wide energy range, accurate energy determination by time-of-flight
• Use time-resolved imaging detectors at RADEN: • Sub-mm spatial resolution
• Sub-µs time resolution
• Mcps count rate
• Strong background rejection
Energy-dependent neutron transmission
Energy meV 1 keV
Wavelength10 10-2
Resonance absorption
Bragg-edge, Magnetic imaging
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µPIC-based Neutron Imaging Detector (µNID)
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• Gaseous time-projection chamber
• CF4-iC4H10-3He (45:5:50) at 2 atm
• µPIC micropattern readout
• Compact ASIC+FPGA data encoder front-end
• 3-dimensional tracking of decay pattern + time-over-threshold
• Accurate position reconstruction
• Strong gamma rejection
400 μm
50 μm
CathodeAnode
100 μm
400 μm
33 cm
E
µPIC-based neutron imaging detector (µNID)
X (strips)0 10 20 30 40 50 60
Relat
ive cl
ock p
ulse
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Entries 28Entries 28Position
X (strips)0 10 20 30 40 50 60Ti
me-
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30Energy DepositionTOT for proton-triton track
Proton Triton
Neutron
Digital encoder with time-over-threshold (TOT)
ThresholdµPIC
Discriminator
Time-over-threshold (∝ energy dep.)
Neutron detection via n + 3He p + tOverall track length ~��mm in gas
µPIC readout 10 cm x 10 cm area, 400 µm pitch x,y strips
Polyimide substrate
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2.5
cm
• FPGA-based encoders for high-speed data acquisition
• Data transfer via Gigabit Ethernet with SiTCP
• FPGA-based system controller
Encoders DAQ PC
SiTCP
EncodersµPIC
Control box DAQ controller System monitor DC power
External timing signals
Vessel pressure
Ethernet
GbE × 4
±2.5V, +3.3V
Ambient temperature
Network
DAQ control
Monitoring
Power
Sensor power
µPIC-based neutron imaging detector (µNID)
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µNID performance and usage at RADEN
Distance from interaction point (mm)-2 0 4 8Ti
me-
over
-thre
shol
d (n
s)
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50
100
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Template for fit
Proton Triton
Base performance characteristics
Active area 10 x 10 cm2
Spatial resolution 0.1 mm
Time resolution 0.25 µs
-sensitivity < 10-12
Efficiency @25.3meV 26%
Count rate capacity 8 Mcps
Effective max count rate > 1 Mcps
Fine spatial resolution using template fit to TOT distribution
Bin size: 40 x 40 µm2
8 cmImage of Gd test target
Detector usage at RADEN (2018A)
µNID 34 days
CCD camera 20 days
Other counting-type 36 days
µNID used primarily for Bragg-edge, magnetic imaging, and phase imaging measurements at RADEN
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µNID control software/analysis GUI
• New DAQ controller hardware and detector control software
• Based on DAQ middleware
• Full integration into beam line control system
• In use since March 2018
• New browser-based UI for offline analysis
• First update with simplified interface, better data visualization, etc.
• In use since April 2018
µNID analysis GUI
Software frameworks at the MLF
IROHA2 – Experimental device control system with web-based UI (MLF)
DAQ Middleware – Detector control and data collection (KEK)
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Automated measurements• Increased rate and integrated
control
• Perform complex measurements more easily
• Computed tomography with TOF
• Quantify effects of scattering, beam hardening, etc.
• Combine with energy-resolved imaging techniques
• Dynamic samples
• Fold TOF info with motion/process frequency
• Currently limited to cyclical processes
P/P0
4 cm4
cm
K. Hiroi et al., J. Phys.: Conf. Series 862 (2017) 012008
5 c
m
Computed tomography Fe step wedge
Polarization image
Magnetic imaging of running motor Model electric motor (provided by Hitachi)
2°/step 91 images
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Ongoing development• 215µm pitch MEMS µPIC for improved spatial
resolution
• µNID with boron converter for increased rate performance
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0.1
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10
100
0.01 0.1 1 10
Co
unt r
ate
(M
cp
s)
Spatial resolution (mm)
µNID
GEM
LiTA12
Current and projected performance of event-type imaging detectors at RADEN
µNID (Optimum rate performance)
Boron-µNID
µNID (MEMS)
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Small-pitch MEMS µPIC
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55 mm
Small-pitch MEMS µPIC• Improve spatial resolution
with reduced strip pitch
• Develop small-pitch µPIC
• Manufacture using MEMS on silicon substrate (by DaiNippon Printing Company, Ltd.) Thru-silicon-via (TSV) µPIC
• Successfully produced 215 µm pitch µPIC (down from 400 µm)
• Small (14 x 14 mm2) and larger area TSV µPICs (55 x 55 mm2) tested at RADEN
100µm 400µm
Cu
10~15µm4~11µm
15µm
Current PCB µPIC (400 µm pitch)
TSV µPIC
215 µm
Surface of TSV µPIC (digital microscope) 215µm TSV µPIC
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First test of TSV µPIC at RADEN (MPGD2016)
280µm pitch (192×192 strips)
215µm pitch (64×64 strips)
Time (ms)0 5 10 15 20 25 30 35 40
sµ
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ulse
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Neutron TOF (MEMS uPIC test)
TSV µPIC test board
Neutron TOF on 215µm section
• No signal measured on 280µm section (gain too low)
• Signal confirmed on 215µm section
• Observed gain instability Gas filling used for test: P10:CF4:He (60:30:10) @2 atm
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Gain instability under irradiation (MPGD2017)
9.5
10.0
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12.0
0:00 1:00 2:00 3:00 4:00 5:00 A
vera
ge
TO
T (c
loc
ks)
Elapsed time (min)
Grounded
Floating • TSV µPIC gain observed to increase with neutron exposure even for 15µm SiO2 layer
• Tried grounding Si substrate
400µmCu
10µm4µm
15µm
Grounding substrate appears to stabilize gain
Necessary anode HV was also reduced
590V
410V
215µm pitch (64×64 strips)
GN
D
Mean TOT vs Time
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Large-area TSV µPIC test at RADEN• Imaging confirmed but spatial
resolution not improved as expected (slightly worse than PCB µPIC)
• Gain instability under neutron exposure improved by grounding substrate but not eliminated
Image taken with 215µm pitch TSV µPIC at BL22
55 m
m§ Gain stability: new MEMS µPIC
with glass substrate (TGV µPIC)
§ Spatial resolution: optimize gas for shorter tracks?
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Time (hours)
TSV185 (4/1) TSV165 (5/22)
500V
510V
460V
Odd behavior near end
Large current (>1 µA) on all strips
Mean TOT vs Time
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Me
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µPIC gain stability at RADEN
MEMS µPIC with glass substrate (12/10)
PCB
Silicon
Glass
Image from digital microscope
• Initial testing performed at Kyoto U. (Abe-san’s talk)
• Gain stability measured at RADEN
– Improved over silicon substrate
– Slightly worse than PCB µPIC
TGV µPIC test board Strip pitch: 215 µm Area: 27.5 x 27.5 mm2
P R E L I M I N A R Y
Imaging with the 215µm MEMS µPICs
400µm PCB µPIC 215µm TGV µPIC
40µm bins 21.5µm bins 21.5µm bins
215µm TSV µPIC
Note: measurement statistics are different for each image
l Image quality with TGV µPIC looks good
l Resolution may be slightly improved compared to PCB µPIC
P R E L I M I N A R Y
Imaging with the 215µm MEMS µPICs
400µm PCB µPIC 215µm TGV µPIC
l Image quality with TGV µPIC looks good
l Resolution may be slightly improved compared to PCB µPIC
40µm bins 21.5µm bins 21.5µm bins
215µm TSV µPIC
Note: measurement statistics are different for each image
P R E L I M I N A R Y
µNID with boron converter
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µNID with boron converter (B-µNID)
~5 mm
Al drift cathode (t=1mm)
µPIC readout
10B coating (t=1.2µm)
• Increase count rate capacity by reducing event size
• 10B ( ,Li) for 3x smaller event size than 3He (p,t)
• Trade-off in spatial resolution
• µNID with flat boron converter (for initial testing)
• Thin, 1.2µm 10B layer low efficiency (3~5%)
• Need to consider ways to improve detection efficiency
10cm
10B (t = 1.2µm)
Expect 20~25 Mcps count rate and 0.4 ~ 0.5 mm spatial resolution
Boron converter installed in µNID
Underside of drift plane
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Position (mm)10 20 30 40 50
Neut
ron
trans
miss
ion
0.6
0.7
0.8
0.9
1.0 0.9 0.8 0.70.6 0.5
0.4
Line-width (mm)
Spatial resolution study at RADEN• Study of spatial resolution, event size
vs. gas pressure (1.2 ~ 1.6 atm)
• L/D:1000, Exposure time: 15 mins
• Spatial resolution estimated from contrast of line-pairs (MTF)
• Maximum count rate at hardware limit: 22 Mcps @1.6 atm
Pressure (atm) 1.2 1.4 1.6
Average hits/event 5.86 5.42 4.82
MTF @0.6mm 27% 36% 41%
Spatial resolution @10% MTF (mm) 0.50 0.48 0.45
Gas pressure: 1.4 atm Bin size: 200 x 200 µm2
Contrast (MTF) from fit of sine curves
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Summary• Standard µNID detector is in regular use at RADEN
• Integration into RADEN control system greatly improved usability
• Incremental improvements in spatial resolution, rate performance
• MEMS µPICs for improved resolution
• TSV µPIC gain stability initially seemed to be improved with grounded substrate, but long-term operability may be adversely affected
• Large-area TSV µPIC � image quality worse than PCB µPIC (gain instability?)
• TGV µPIC � improved gain stability, good image quality
• µNID with boron converter for increased rate
• Proof-of-principle study completed � confirmed peak rate of 22 Mcps and spatial resolution of 0.45 mm
• Next: gas optimization for further reduced event size, increase efficiency of converter
• Will make a new, dedicated Boron-µNID system for RADEN next year
�15�MPGD 14 Dec 2018 J. Parker