Abstract #: 1054 Conference: NSS (Oral)
Accelerator Technologies and Beam Line Instrumentation

X-Ray Detection Using SOI Monolithic Sensors at a
Compact High-Brightness X-Ray Source Based on
Inverse Compton Scattering
T. Miyoshi1, Y. Arai1, M. Fukuda1, J. Haba1, H. Hayano1, Y. Honda1, A. Kuramoto2,
K. Sakaue3, H. Shimizu1, A. Takeda2, J. Urakawa1, K. Watanabe1
1Institute of Particle and Nuclear Studies, HIGH ENERGY ACCELERATOR RESEARCHORGANIZATION (KEK), Tsukuba, Japan
2Graduate School of High Energy Accelerator Science, The Graduate University for Advanced
Studies (SOKENDAI), Tsukuba, Japan
3Research Institute for Science and Engineering, Waseda University, Tokyo, Japan

N42-1, Nov. 1 (Thursday) @ 16:30 in room: Magic Kingdom Ballroom 3See also : N14-1 (Poster), “Development of a Compact Laser-Compton X-Ray
Source Using Optical Super-Cavity at KEK-LUCX”, K. Sakaue et al.
1

Outline

Laser Compton scattering
Quantum Beam (QB) accelerator- Electron accelerator- Laser- X-ray detector
Pre-experiment of X-ray detector
X-ray detection – status of accelerator
Summary2

Inverse Compton scattering(Laser-Compton Scattering, LCS)
Features of LCS X-ray- good directivity- angularly distributed- quasi-monochromatic in small
solid angles
Electron energy (Ee)

 ~ 80 @ Ee = 40 MeV
Maximum flux: Head-on collision
Maximum X-ray Energy ~ 30 keV

Utilization for material science, etc
Ultra-short pulse,
high-peak power lasers+Low emittance, High brightness,
electron source=High flux X-ray source(can be a “Compact” X-ray sourcecompared with Synchrotron facility)3

A compact high-brightness X-ray source@ Superconducting Accelerator Test Facility (KEK STF)
The Quantum Beam Technology Program of the Japanese Ministry of
Education, Culture, Sports, Science, and Technology (MEXT) 2008.9 to 2013.3

Goal:
1.3 x 1010 photons/sec 1% bandwidth@ 5 Hz, 40 MeV, 10 mA beam
Beam & Laser collision point
Beam dump
Passed w/o beam loss
in April 2012

Electron Accelerator
20 deg bend

Laser
40 deg bend

X-ray detector

From the cathodeTo the dump ~ 23m
Beam operation (~ Dec. 2012)4

Electron beam

(C) Rey.Hori

Capture module (SC 9‐cell cavity x 2)
MHI‐12: Max Eacc = 40 MV/m (V.T.)
MHI‐13: Max Eacc = 33 MV/m (V.T.)
PhotocathodeL‐band RF gun(2.6MW input)

DRFS klystronElectron beam generation
Specification (Goal)
Pulse length 1 ms
Repetition rate 5 Hz
Bunch Spacing
6.15 ns (162.5 MHz)
Number of Bunch 162500
Bunch Charge
62 pC
Total charge / pluse 10,000 nC
Beam Current
10 mA (~7mA@Mar.)
Beam size at collision point ~ 10 m (36m in  @ July)
Bunch length
12 ps (Laser, FWHM)
Max. Beam Enegry 40 MeV
Beam power 2.0 kW (40 MeV Beam)

Laser gate

30~40pC/bunch
162448 bunches in 1ms rf pulse
Beam energy ~ 3MeV5Laser system
Pump LDOscillator
100mW

162.5MHz mode-locking
2D four mirror cavity togenerate X-ray with two
cylindrical lenses

60W

EO

30mJ/pulse

Burst Amp
By 100 times(10uJ/pulse)

Fiber Amp
(100nJ/pulse)

Short pulse 4.3 ps in 6

SOI X-ray detector
One of the Detector Technology Project (DTP) at KEK since 2005
Monolithic silicon pixel detector with Silicon-On-Insulator technology

CircuitInsulator

Absorption coefficient(NIST calculation)

SensorEnergy spectrum &High-resolution X-ray image
can be measured in one detector!
Almost inactive with -ray more than 100 keV-ray reaction probability at SOI layer(40nm) and bulk (260um)
 very small ~ 0.6% @ bulk
Good for high radiation background environment such as the QB Accelerator
7

Integration-type SOI pixel detector (INTPIX4)

10.2 mm15.3 mm・developed in 2009
・832 x 512 pixels (14x8 mm)
・17m pixel size
・300V for full depletion(resistivity=700 Ohm-cm)

INTPIX sub-board
INTPIX
Analog output

DAQ board(“SEABAS1/2”)
Analog toDigital Converter(ADC) 12-bit

PC@control room
Data transfer
Ethernet
Using “SiTCP”
8Pre-experiment at KEK Photon Factory (KEK-PF)
Integration time 200us/image x [ 50 dark images + 300 X-ray images ]BL-14CSi(220)asymmetricMirror

30keV
monochromatic X-ray

Fish bone

INTPIX4
Photon accumulation
Photon counting~250ADU
Single hit onlyin 256x256
pixels(300 images x200us)
Energy Spectrum

ADU

X-ray image (net exposure 60ms)

9Detector Setup at QB accelerator
X-ray(distance fromcollision point
~ 6m)

SOI

X-rayNaI(5mm-thick)

NaI signal by beam loss back ground

20us

X-ray

SOI

Pulse train timing signal (5Hz)
 SOI trigger
 SOI integration gate(changeable, from 40 ns/clk to ~ 1 ms)
Delay timing was adjusted using
NaI background signal from beam loss10

X-ray detection and current status

ElectronLaser

End of October (operation in last week)
Position of laser and electron beam at thecollision point can be adjusted on theflorescence screen[Current issue]- Electron beam requires additional
feedback control system to be stabilized- Laser system optimization is underway.
We are focusing synchronization ofelectron beam and laser with lower
intensity very carefully (to prevent
physical damage first)- Collision tuning and increase of laser
intensity will be performed in November.

Screen captures of florescence screen at the collision point11

X-ray detection : very preliminary analysis
400 bunch (~2.4us) pulse train, ~40 pC/bunch
Counts

Red: “On” beam
- Beam position is adjusted to thelaser position.
Black: “off” beam
- Beam position is off by ~1mm
300 pulse trains accumulation???
‐raybackground

Unfortunately we don’t detect Xray yet due to very weak laser
power currently (to be continued)

Output[ADU]
No signal

We established DAQ system for the measurement of X-ray spectrum
12Summary and near future plan
A compact high-brightness X-ray source based on inverse Compton scatteringhas been developed on the Superconducting Accelerator Test Facility (STF) atKEK.
All the component was installed and we are operating the accelerator.
We are trying to do collision experiment and optimizing electron beam and laser
to reach our goal and demonstrate X-ray imaging by using SOI X-ray detector.
Operation will be continued in the end of December.
To be done:- Stabilization of electron beam at the collision point - within a few microns- Electron beam size ~ 10 m / laser size ~ 20 m- Increase of laser intensity with the synchronization to electron beam
- measure X-ray intensity  1.3 x 1010 photons/sec 1% bandwidth@ 5Hz, 40 MeV - 10mA electron beam & 30mW/pulse laser13