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GEM basic test and R&D plan. Takuya Yamamoto ( Saga Univ. ). Introduction. GEM is used for the sensor part of TPC. Beam test that examined a basic performance of GEM was done. GEM. Fuchigami GEM. 70μ m. 70μ m. 60μ m. 140μm. 10cm. CERN GEM. 5μ m( Cu ). 50μ m ( KAPTON ). 5μ m( Cu ). - PowerPoint PPT Presentation
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GEM basic test and R&D plan
Takuya Yamamoto ( Saga Univ. )
Introduction
GEM is used for the sensor part of TPC.
Beam test that examined a basic performance of GEM was done.
GEM
10cm
140μm
CERN GEM
5μ m( Cu )
5μ m( Cu )
50μ m( KAPTON )
70μ m
60μ m
Fuchigami GEM
70μ m
Outline of BEAM TEST
Compares of CERN and Fuchigami. •Used and tested at Hiroshima Univ. Refer
150MeV Electron Beam
•Three GEM was installed in the chamber.
•The gas used the P-10 gas.
•Reading PAD was used the one of PrototypeTPC.
•The trigger counter was set up back and forth.
2mm
6mm
Dielectric board
GEM3GEM2GEM1
PAD
Drift area
( Cathode)
( Anode)GND
213V/cm
The space between PAD is all 0.3 mm.
235mm
Transfer area 2kV/cm1.5mm
Induction area 3kV/cm1mm
Eve
nts
C.O.G. [mm]
( Fuchigami GEM : Layer 4 ( VGEM = 330 ( V ) )
Residual
Eve
nts
Track [mm]
180
100200
400
- 3 40- 3 40
Residual [mm]
Eve
nts
0- 2 2
0- 2 2
Residual [mm]
1000
σ ≒ 320 [ μm]m
σ ≒ 380 [ μm]m
Residual = C.O.G. - Track [μm]E
ven
ts
350
Fuchigami GEM
290μ m
CERN GEM
340μm
Each of Layer4
Positional resolution
Fuchigami
CERN
Track / Residual
Fuchigami GEM : Layer 4 ( VGEM = 330V ) CERN GEM : Layer4 ( VGEM = 330V )Track [mm] Track [mm]
CERNFuchigami
Res
idu
al [
mm
]
Res
idu
al [
mm
]
00
Systematic behavior is seen
2
- 2
2
- 2
0-3 4 0-3 4
Size of electron distribution
• Response Function
Rat
io o
f ch
arge
(%)
100
50
0
Distance from PAD to Track(mm)0-4 4
Distribution of charge seen from each pad of one layer.
0
Distance from PAD to Track(mm)0-4 4
100
50
CERN GEM : Layer4 ( VGEM=330V )Fuchigami GEM : Layer 4 ( VGEM = 330V )
Fuchigami CERNR
atio
of
char
ge (%)
Difference of pulse height
CERN
Fuchigami
sumADC
even
ts
ADC counts
1count = About 0.25pC
● CERN
〇 Fuchigami
The gain of Fuchigami GEM is about 0.8 times CERN GEM.Fuchigami GEM : Layer4 ( VGEM = 320V )
CERN GEM : Layer4 ( VGEM=320V )
Pad raw No.(Layer)
Result of BEAM TEST
•Obtained Position resolution
•Fuchigami About 290[μm ]
•CERN About 340[μm ]
( Non Magnetic field)
In SN influences
•Fuchigami GEM operated as well as CERN GEM , too
•Some problems happened during Beam test
•The durability of GEM
Discharged GEM( CERN)
Normal
Damaged
In developing
Durability of GEM
When HV is raised and beam ON, GEM is discharged.
When the numbers of ions collected in the hole increase too much,
and copper is transformed.
As a result, it energizes between both electrodes.
Hypothesis
Development of GEM①
•To investigate the cause of the electrical discharge, the segment does GEM.
10cm
Possible to impress HV to nine separate GEM
Development of GEM②
•We try Nickel coated GEM.
Nickel
Development of GEM③
•The load of one hole is decreased by increasing the number of holes. 9cm
3cm
•The diameter of the hole is 30μm.
•Laser etched by 50μm pitch.
Some surfaces are uneven because of the heat of the laser.