Transcript Document

Present Status of GEM Detector
Development for Position Counter
1.
2.
3.
4.
5.
6.
7.
Introduction
GEM
Readout Board
Fabrication Test
Large GEM
Readout Electronics
Summary
Kunihiro Fujita
Research Center for Nuclear Physics, Osaka University
Introduction
• Application to Nuclear Physics Experiment
– Coherent Pion Production
• Requirements
– high position resolution (< 100um)
– radiation tolerance (> 1Mcps)
• Concept
– GEM
– Readout Board with Micro Pattern Strips
trigger
tracking
Sci 2
Sci 1
position 2
position 1
GEM detector
overview of the detector system
charged particle
GEM
•
Fabrication procedure
– Wet etching (supplied by CERN)
⇒ high quality and low cost ~ 700,000yen/10sheet
– Plasma etching ( by Fuchigami Micro Co., Ltd.)
⇒ large size is difficult
– Laser etching ( by Fuchigami Micro Co., Ltd.)
⇒ larger size needs higher cost ~ 3,700,000yen/20sheet
lowest cost and stable operation
⇒ We decide to use CERN-GEM
aramid carbon (6μm)
Drift (3 kV/cm)
100mm
GEM 1
GEM 2
E
ΔV
~400V
GEM 3
Readout Board (GND)
140μm
Readout Board (ROB)
• Readout Board
– high position resolution
– 2 dimensional readout
• components
– double layers of perpendicular copper strips
• fabrication procedure
– close to one of used for GEM
• wet etching ~ Raytech, CERN
• laser etching ~ Raytech
100mm
Kapton (50um) Cu (4um)
80um
100mm
340um
400um
Cu (4um)
G10 (100um)
electron microscope image and schematic image
Flexible Printed Circuit
500 channel
prototype
Fabrication procedure of ROB
• Raytech
– Wet etching
– Laser etching
• CERN
• Cost
– 1,000,000/3sheet
•Problem
–Over etching
–Mountain shape
•only 50um kapton
Fabrication test
• Components
– 3GEM electrode
– 128ch bundled Micro Strip
• test procedure
– 55Fe source
– Charge amp. → Camac ADC
– calibration for gain
• result is consistent with CERN & CNS
prototype chamber
Triple GEM effective gain
ArCO2
Effective Gain
ArC4H10
340
pulse height distribution.
350
360
370
ΔVgem
380
the measured amplification
factor in each gas.
390
400
410
[1] S. Bachmann et al., NIM A 438 (1999) 376.
[2] M. Inuzuka et al., NIM A 525 (2004) 529.
Large Size GEM
•
soldering
Active area
– 307.2x 50.2 mm2
•
pattern 321
What should be solved
– discharge propagation
• over 80cm2
– H.V. terminal
•
Solution
50.2
divide
– 2-segmented
– protection resistance
– 3 patterns of H.V. terminal
307.2
H.V.
GEM holes (standard)
triangular pattern
size: 70um
cross section
pitch: 140um
discharge signals on anodes
S. Bachmann et al., NIMA 479(2002)294
200um separation
10M
Connection
Readout Board
half-pitch connector
FPC connector
FPC
•
Propose
– charge transfer from ROB to Readout electronics
•
Components
– Flexible Printed Circuit Board
– its connector
•
Advantages
– low noise transfer
– wire bonding less
Analog-LSI
Front-end Card
Readout
Electronics
Development of Readout System
•
Requirements
–
–
–
–
huge number of readout channel
high counting rate
high trigger rate
small space
→ ~2000ch
→ ~1M count s-1 (detector total)
→ ~100 kcps
→ installed in the magnet
ADCs
for eachreadout
channel? high speed data taking
multi
channel
analog
GEM
detector
radiation hard environment
•
digital
digital
small number of modules
and signal lines
Concept
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–
Computer
multi channel processing
high speed digitization and data transfer
small number of modules and low cost
easy to debug and connect to other devices
easy to debug
Readout Electronics (Space Wire)
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Components
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multi channel processing analog LSI
Flash ADC
Space Wire Protocol (IEEE 1355)
Complex Programmable Logic Device
block diagram
analog LSI
Space Wire host
Flash ADC
Connector Board
(hub)
CPLD
single line
Va32_Rich2
~2000ch
•
sample & hold
sequential read
GEM
detector
← sampling/hold, shaping, and multiplex
← high speed digitization
← simple and high speed data transfer protocol
← reconfigurable logic unit
control / data
4 lane
Space Wire protocol
(LVDS) 1 lane
Advantages
–
–
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multi channel LSI and serial data transfer ← small number of modules and cables
high speed data transfer
← MAX 400Mbps
easy to fit to other detectors
← by reconfigure CPLD only
low cost/channel
← small number of module
Space Wire is simple protocol
← performed by only one CPLD chip
Computer
Example and Application
•
•
multi channel readout
– silicon strip detector [3]
– CdTe detector [3,4]
– multi-anode phototube [5]
easy to fit other detector
– replacement the detector
Energy Spectrum by using New Readout System
Left figure shows the photon yield at each channel of one M-PMT. Right figure shows
– performed by reconfiguring FPGA
energy spectrum obtained from summing up the photon yields.
This result shows that a newly developed
read-out
can board
be used to read-out MultiFADC
& system
CPLD
reconfigure
channels detectors.
GEM
40K
CPLD
17%（FWHM）
2.2 keV/ch
Sum
40K
17%（FWHM）
2.2 keV/ch
energy distribution measured by the M-PMT.
readout system for M-PMT
Fig8.
Energy distribution
in Mitani
the NaIetmeasured
by theNucl.
M-PMT(H6568-Mod).
[3] T.
al., IEEE Trans.
Sci., 50 (2003) No.4 1048
[4] H. Tajima et al., IEEE Trans. Nucl. Sci., 51 (2004) No.3 842
[5] H. Nakamura, NDM03 poster session.
Summary
• We develop GEM Position detector for tracking of
charged particle
• Stable operation with high gain
• High resolution will be performed by Micro
Pattern Readout Board
• Readout Electronics is consist of Multi-Channel
LSI and Serial data link system
• Now, Hardware is almost ready
• Experiment ~ will be performed in next April