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

�15�MPGD 14 Dec 2018 J. Parker

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

�15�MPGD 14 Dec 2018 J. Parker

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

�15�MPGD 14 Dec 2018 J. Parker

µPIC-based Neutron Imaging Detector (µNID)

�15�MPGD 14 Dec 2018 J. Parker

•  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

05

101520253035404550

Entries 28Entries 28Position

X (strips)0 10 20 30 40 50 60Ti

me-

abov

e-th

resh

old

(clo

cks)

0

5

10

15

20

25

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

�15�MPGD 14 Dec 2018 J. Parker

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)

�15�MPGD 14 Dec 2018 J. Parker

µNID performance and usage at RADEN

Distance from interaction point (mm)-2 0 4 8Ti

me-

over

-thre

shol

d (n

s)

0

50

100

150

200

250

62

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

�15�MPGD 14 Dec 2018 J. Parker

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)

�15�MPGD 14 Dec 2018 J. Parker

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

�15�MPGD 14 Dec 2018 J. Parker

Ongoing development•  215µm pitch MEMS µPIC for improved spatial

resolution

•  µNID with boron converter for increased rate performance

�15�MPGD 14 Dec 2018 J. Parker

0.1

1

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)

�15�MPGD 14 Dec 2018 J. Parker

Small-pitch MEMS µPIC

�15�MPGD 14 Dec 2018 J. Parker

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

�15�MPGD 14 Dec 2018 J. Parker

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

Coun

ts/p

ulse

/25

0

0.02

0.04

0.06

0.08

0.1

0.12

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

�15�MPGD 14 Dec 2018 J. Parker

Gain instability under irradiation (MPGD2017)

9.5

10.0

10.5

11.0

11.5

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

�15�MPGD 14 Dec 2018 J. Parker

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?

11

12

13

14

15

0:00 2:00 4:00 6:00 8:00 10:00 12:00 14:00

Me

an

TOT

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

�15�MPGD 14 Dec 2018 J. Parker

12

14

16

18

20

22

24

0:00 2:00 4:00 6:00

Me

an

TO

T

Time (hours)

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

�15�MPGD 14 Dec 2018 J. Parker

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

�15�MPGD 14 Dec 2018 J. Parker

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

�15�MPGD 14 Dec 2018 J. Parker

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