development of hard x-ray detector with gem
DESCRIPTION
Development of Hard X-ray Detector with GEM. Shoji Uno (KEK) M. Sekimoto, T. Murakami, T. Uchida (KEK) T. Koike (Tokyo University of Science) M. Kuroishi (Shinshu University) KEK Detector Technology Project MPGD2009 Crete, Greece 12 June 2009. 10cm. 10cm. - PowerPoint PPT PresentationTRANSCRIPT
Development of Hard X-ray Detectorwith GEM
Shoji Uno (KEK)M. Sekimoto, T. Murakami, T. Uchida (KEK)
T. Koike (Tokyo University of Science)M. Kuroishi (Shinshu University)KEK Detector Technology Project
MPGD2009 Crete, Greece12 June 2009
GEM foils made by Japanese company
• New method (plasma etching) was tried in several years ago. – Not chemical etching (CERN) – M. Inuzuka, et al., NIM A 525(2004) 529-534
• Laser + Plasma – To reduce sparks– T.Tamagawa, et al., NIM A560(2006) 418
• It is convenient for us to make new types of GEM foils.– Fine pitch/small hole : 50m/30m
• Better resolution Cosmic X-ray polarimeter• RIKEN
– Thicker/thinner : 100(150)m/ 25(12)m • Higher gas gain : a part of my talk
– S.Uno, et al., NIM A581 (2007) 271• Higher transparency : Gating grid for TPC
– Coated GEM• Boron : Neutron detection • Gold : Hard X-ray my talk• CsI : Hamamatsu Sekiya’s talk
10cm
10cm
Scienergy Co., Ltd. (Japanese company)http://www.scienergy.jp/
Ar-CO2
P10
Triple GEM with 50mt
Single GEM with 100mt
100mmt GEM : Hole diameter 70m (90m)Pitch 140m
Double GEM with 100mt GEM 70m
Thickness(m)
VGEM1
(V)VGEM2
(V)Sum(V)
Gain Comments
100/100 557 557 1114 1.3x104
100/100 579 579 1158 4.3x104
100/100 651 506 1157 5.4x104
100/50 675 375 1050 4.8x104 Stable
100/50 650 400 1050 5.0x104 Stable
Triple 390 × 3 1170 3.0x104
Diameter:90m for 100mt GEM :70m for 50mt GEM
Combination of different thickness GEM
Hard X-ray detector• Hard X-ray can even penetrate a thick iron plate and a concrete
block. Therefore, it is useful for non-destructive inspection in industrial purpose.
• Usually, Xenon gas has been used for detection of X-ray.
• But, efficiency is not so high for hard X-ray ( >~60keV).
• Solid converter (Gold) is used for detection of hard X-ray.
• Range of produced electron is very short. Gold layer should be thin. Then, many thin gold layers are necessary to get higher efficiency.
Gold plated GEMto get higher efficiency
for hard X-ray with higher energy
Au 3m Cu 1m
Polyimide 50m
X-Rays
Electrons
Standard GEM+Gold Plating
141keV γ-ray
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.00 0.05 0.10 0.15
Electron Energy (MeV)
Rel
ativ
e In
tens
ity
8
Simulation Study
Energy spectrum in gas volume for produced electron in gold layer
0
5
10
15
20
25
30
0 10 20 30 40 50
Number of GEMs
Eff
icie
ncy(
%)
9
Optimization of Gold thickness
0.0
0.2
0.4
0.6
0 5 10 15 20 25
Thickness of Gold Layer (m)
Effic
ienc
y (%
)
Photon Energy: 141keV
1m
2m
3m
4m
5m
10m
Simulation
Chamber structure
Au-GEM3m
2mm
2mm
Readout board X-Y strip0.8mm pitch 120+120
Multiplication
X-ray conversion layersEffective gas gain ~ 1
Gas:Ar-CO2(70-30)
Ground
100mt GEM1mm1mm1mm
1mm
1mm
50mt GEM
Drift planeAu 3m
0
1
2
3
4
0 1 2 3 4 5
Number of Au-GEM
Rel
ativ
e V
alu
e
11
Experimental result
57Co ( 122keV )
Thickness of Gold Layer: 3mon both surfaces
Gold coated GEMC
oun
tin
g ra
te (
rela
tive
val
ue)
GEMChamber
• I/F– One HV cable– Five LV cables– One Ethernet cable
• Electronics– Four ASIC boards– One FPGA board
• FE2007 ASIC– By Y. Fujita (KEK)
• Data transfer and Control through Ethernet– SiTCP ( by T. Uchida)– Using Note-PC
Present Detector System
Low Voltage
Electronics
Note PC
Ethernet
Detector size 150mm×150mm×510mm
High Voltage
Compact and Portable System T.Uchida et. al., "Prototype of a Compact Imaging System for GEMdetectors," was published on IEEE TNS 55(2008)2698.
0
0.2
0.4
0.6
0.8
0 20 40 60 80 100 120 140
Photon Energy (KeV)
Rel
ativ
e In
tens
ity
X-ray irradiation test
• Medical X-ray Generator
– Voltage 120kV
– Current 1mA 0
200
400
600
800
1000
1200
0 1 2 3 4 5
(mA)管電流値
(kHz)
計数
率
Current (mA)
Cou
ntin
g ra
te (
kHz)
Energy Spectrum
Data Taking Rate
Without filterWith Mo 0.3mmt
Max. rate1.1MHz
2D Image for Hard X-ray
Clear 2D image could be seen.
96mm96
mm
Pinhole ( 0.5mm ) Irradiation time:100sec
0.8mm
0.8m
m
Iron Plate and Bars• On the Detector
1. Grid (Laminate structure of Lead and Aluminum)
To reduce scattering X-Rays 2. Iron plate : 10mm thickness 3. Four bars with different diameter
0.4mm2mm
0.9mm4.2mm
Iron Platewith holes
9mm 8mm 7mm
6mm 5mm 4mm
3mm 2mm1mm
Depth:
Iron plate with 10mm thickness Hole diameter : 6mm
Iron Bars inside Concrete
Thickness of Concrete :10cmIrradiation Time : 100sec
9~10mm 6mm 15~17mm
Four types of Iron Barsbefore molding
Concrete sample with Iron Bars
10cm
Summary• Japanese company (Scienergy Co., Ltd.) can produce various
GEM foils.
• Flexible 100mt GEM is effective to get higher gas gain for single GEM structure.
• Gold coated GEM foils were manufactured.
– Higher efficiency was obtained with more GEM foils.
• A prototype of hard X-ray detector with gold coated GEM was
constructed.• Performance study was done with X-ray generator.
– Clear 2D image could be seen.
– Hard X-ray could be observed through the thick iron plate with 10mm thickness.
– Iron bars could be seen inside concrete block.