development of tracking detector with gem kunihiro fujita rcnp, osaka univ. yasuhiro sakemi cyric,...
TRANSCRIPT
Development of Tracking Detector with GEM
Kunihiro Fujita RCNP, Osaka Univ.Yasuhiro Sakemi CYRIC, Tohoku Univ.
Masaharu Nomachi Dep. of Phys. , Osaka Univ.
• Short range component of Nuclear force: g’– ++g’ model
• Landau-Migdal parameters: g’ (g’NN, g’N, g’)– g’ : Few experimental information
• Coherent pion production is sensitive to g’
Physics Motivation
),q(eff V ),(),( qq VV LMV
universality(gNN=gN=g)
g’ affect • Critical Density of Pion Condensation• property of high density nuclear matter
g’
n
p
t
Initial state Intermediate state Final state
“Absorb” the virtual pion(off-shell pion)
“Emit” the real pion(on-shell pion)
Propagation of -h states
RecoilHe3 He3
Virtual Pion : +*
~ interaction (w,q)
Ground State
is generated sequentially
pion, charged particle
Detector Requirement• Motivation
– Tracking of low energy (< few hundred MeV) charged particle
• Requirements ( why GEM? )– high position and angle resolution
• spatial : <100m & angle: < 2 mrad– rate capability : >100kcps– can be operated under high magnetic field: < 1 Tesla– boundary condition ~ narrow space
neutron70m TOF
TOF counter (NPOL2)
10 cmcm
Magnet & Counter Box
400 MeV proton from Ring cyclo.
Swinger Magnet (proton is bent by 90 deg)
B~1.5T
Detectors
• Size : 1×1×0.1 m3
• 4 liquid, 2 plastic scintillators with charged particle catcher
• Energy resolution : 500 keV• Detection efficiency : 15 %
• Flight Path was set to 70m• Developed by Tokyo Univ. group
• Gas Electron Multiplier (GEM) detector ~ Tracking
newly developed for this experiment
• Plastic Scintillator ~ Trigger– Size : 320×50×10 mm3
– 2 plastic scintillators– Fine Mesh PMT ~ gain is 105 at 1 Tesla
Trigger counter
typical
Tracking counter
Neutron Counter (NPOL2)
Pion Counter
Detector specification• To Get position information for Two layers• Component
– Cascade GEM structure ~ Three layers– Two dimensional Readout Board– Charge Information : Multi channel ADC
• Specification – high position resolution
: 100m (designed value)– radiation tolerance – tolerance for magnetic field: ~1 Tesla
1st Plane
2nd Plane
Electronics
Cable (analog sig.)
77mm452mm
110mm
cathode
3mm
1mm
1mm
1.5mm
Readout Board
GEM1
GEM2
GEM3
H.V.
GEM
50307.2
• CERN-GEM (supplied by GDD group)
– Active Area: 307.2x50 mm– Segmented by two area
• protection from discharge
– Standard Material & Size • Cu-PI-Cu 5-50-5m• hole 70m, pitch 140m
GEM holes (standard)triangular pattern
size: 70umpitch: 140um cross section
200m separation
H.V.
Triple GEM effective gain
1.E+02
1.E+03
1.E+04
1.E+05
340 350 360 370 380 390 400 410ΔVgem
Effective Gain
ArCO2
ArC4H10
the measured amplification factor in each gas.
Readout Board and Connector
• Readout Board– Same size with GEM– Base : G10 50m– Cu-PI-Cu : 5-25-5 m– Strip width
• horizontal (x) : 80 m• vertical (y) : 340 m
– pitch: 400 m
• Connection– Flexible Cable– Sandwiched Structure :
GND-Signal-GND
Readout Board (supplied by ‘RAYTECH, INC.’)
Flex Cable (supplied by ‘TAIYO Ind. CO., LTD’)
768ch
120ch
connect 400m
340m
80m
Readout Electronics
Readout ElectronicsAnalog-LSI boards
Readout Board
FPC (one of 14)
to VME module
Va32_Rich2
~2000ch
I/O Board
Space Wire Protocol
Analog MUX
Trig/Ctrl
data
CPLD
Flash ADC
• Analog– VA: amp, sample/hold, serialize– TA: shaper, discriminator trigger– Dynamic range : ~ 140 fC– 256ch outputs are multiplexed
• Digital– ADC: 12-bit– Serial Data Transfer (LVDS)– Sparse Data Scan : Skip un-triggered
chip
• Data Transfer Rate – ≳ 2kHz limited by FADC
to VME
Data Acquisition• SW-VME module
– transceiver( ADC data, control commands)
– decoder– memory control
• Trigger module– decide coincidence level GEM, Trigger SCI, and neutron counter
FPGA GDG
VME bus
x8
in x2out x2
SW-VME x4
memory to/from neutron DAQ
TriggerCPLD
Trigger Sci.2ch
data /control
trighold
from GEM
Experiment (1)
• Date: July 2006• Reaction: 12C(p,p’), faint beam (direct)• Beam:
– particle: proton– energy: 392MeV– rate : <2k count / sec
• Detector Setting– Gas : Ar/CO2 (7:3)– Vgem : ~ 410V (gain ~12k)
proton
GEM
Spectrometer (Grand Raiden)
proton
trigger counter
GEM
Result(1)• Position Dependence of GAIN
– uniformity was was 2%(RMS) for x1, and x2 3~5% for y1, and y2
• Angle Dependence of Cluster Size (CLS)– at 0 deg. cls ~ 3, 4 – at 40 deg. cls > 10
Fig1. position dependence of gain
=0 deg.
=40 deg.
Tracking Result
beam position with three magnetic field settings.
FWHM:~2mm (= 200 keV)
[mm]
•Tracking information was observed ~ peak width was 2mm (include beam size)
Experiment(2)
• Date: October and November 2007• Reaction: 12C(p,n+)12C(g.s.)• Beam:
– particle: proton– energy: 20MeV, 392MeV– rate : <2k count/sec (pion counter)
• Detector Setting– installed in the high Magnetic field
~1 Tesla– GEM + trigger SCI + neutron counter
proton
+neutron
12C Target
proton beam
neutronpion counter
50cm
Swinger Magnet
Result(2)
• Gain dependence in Magnetic field– measured with 3 settings 1.1, 0.98, and 0.75T– fluctuations was less than 3%
• position resolution– 2.3mm (FWHM)
peak position for each B
ADC
FWHM:~2.3mm
SUMMARY• We developed GEM detector for nuclear experiment.• Large size GEM and Two dimensional Readout Board
is made.• Readout Electronics was developed with VA/TA
chip, FADC board, SW-VME and CPLD module.• Beam test was performed and specification was
estimated.• Data run was performed and position information
was acquired successfully in the high magnetic field.
Next Plan• improve DAQ system for the high counting rate• Data analysis with GEM + neutron counter
Missing Mass Spectrum