Present Status of GEM Detector Development for Position Counter 1.Introduction 2.GEM 3.Readout Board 4.Fabrication Test 5.Large GEM 6.Readout Electronics 7.Summary Kunihiro Fujita Research Center for Nuclear Physics, Osaka University

IntroductionIntroduction Application to Nuclear Physics Experiment –Coherent Pion Production Requirements –high position resolution (< 100um) –radiation tolerance (> 1Mcps) Concept –GEM –Readout Board with Micro Pattern Strips Sci 1 Sci 2 GEM detector position 1 position 2 charged particle trigger tracking overview of the detector system

GEMGEM 100mm 140μm 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 Drift (3 kV/cm) GEM 1 Readout Board (GND) ΔV ~400V aramid carbon (6μm) GEM 2 GEM 3 E

Flexible Printed Circuit 500 channel 100mm Readout Board (ROB) electron microscope image and schematic image Cu (4um)Kapton (50um) Cu (4um) G10 (100um)400um 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 340um 80um 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 – 55 Fe source –Charge amp. → Camac ADC –calibration for gain result is consistent with CERN & CNS the measured amplification factor in each gas. [1] S. Bachmann et al., NIM A 438 (1999) 376. [2] M. Inuzuka et al., NIM A 525 (2004) 529. pulse height distribution. prototype chamber

Large Size GEM soldering pattern GEM holes (standard) triangular pattern size: 70um pitch: 140um cross section 200um separation H.V. divide 50.2 Active area –307.2x 50.2 mm 2 What should be solved –discharge propagation over 80cm 2 –H.V. terminal Solution –2-segmented –protection resistance –3 patterns of H.V. terminal 10M pattern 2pattern 3 discharge signals on anodes S. Bachmann et al., NIMA 479(2002)294

ConnectionConnection Propose –charge transfer from ROB to Readout electronics Components –Flexible Printed Circuit Board –its connector Advantages –low noise transfer –wire bonding less Front-end Card Readout Electronics Analog-LSI half-pitch connector FPC connector Readout Board FPC

easy to debug Requirements –huge number of readout channel→ ~2000ch –high counting rate→ ~1M count s -1 (detector total) –high trigger rate → ~100 kcps –small space→ installed in the magnet Concept –multi channel processing –high speed digitization and data transfer –small number of modules and low cost –easy to debug and connect to other devices small number of modules and signal lines high speed data taking Computer analog digital radiation hard environment GEM detector ADCs for each channel? Development of Readout System multi channel readout

Readout Electronics (Space Wire) Components –multi channel processing analog LSI ← sampling/hold, shaping, and multiplex –Flash ADC ← high speed digitization –Space Wire Protocol (IEEE 1355) ← simple and high speed data transfer protocol –Complex Programmable Logic Device ← reconfigurable logic unit Advantages –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 sample & hold sequential read Space Wire protocol (LVDS) Space Wire host Computer single line block diagram control / data GEM detector analog LSI Va32_Rich2 ~2000ch4 lane1 lane Flash ADC CPLD Connector Board (hub)

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 –performed by reconfiguring FPGA [3] T. Mitani et al., IEEE Trans. Nucl. Sci., 50 (2003) No [4] H. Tajima et al., IEEE Trans. Nucl. Sci., 51 (2004) No [5] H. Nakamura, NDM03 poster session. readout system for M-PMT energy distribution measured by the M-PMT. GEM reconfigure CPLD FADC & CPLD board

SummarySummary 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