Basic characteristic of
100μmGEM
K,Kadomatsu (saga.u)
池野正弘、宇野彰二、内田智久、氏家宣彦、関本美智子、
田中秀治、田中真伸、仲吉一男、村上武(KEK)
青座篤史、杉山晃(佐賀大)
中野英一、中川伸介(大阪市大)
杉山史憲(東京理科大)
Motivation
We want to get high gain
• To understand a basic characteristic of 100
mmGEM.
• We inspect that 100 mmGEM can provide
higher gain than 50 mmGEM.
GEM Foil
φ = 70μm
10cm
8 μm
10cm
5 μm
50 μm
8 μm
5 μm
Polyimide
100μm
Polyimide
Cu
ScienergyCu
Co., Ltd. 製
Single 100mm-GEM Test Chamber
PCB
GAS
Ar-CO2(70/30)
□15mm×15mm
36=6×6
1mm
55Fe
(5.9 keV X-ray)
ED=0.75kv/cm
EI=7kv/cm
Drift Plate
2mm
Drift Area→ED
100mm-GEM1
2mm
2200pF
Read out
Induction Area →EI
PCB
2200pF
Read out
Single GEM
ΔVGEM
10000
もう少し、高い電圧を
掛けれるようにしたい
1000
100μm(single)
Higher Gain is
obtained with
100μmGEM
Gain
50μm(triple)
100
We normalize ΔVGEM of 100μmGEM to
Δ VGEM of 50μmGEM
10
250
275
300
325
350
375
400
ΔVgem/2 (100μ) = ΔVgem (50μ)[V]
Single GEM
ED dependence
Collection Efficiency
1.2
1
100mmGEM
ΔVGEM=660V
EI=6.0kV/cm
Ehole=61.9kV/cm
0.8
0.6
100μGEM
50μGEM
・AAHEN
測定
50mmGEM
ΔVGEM=350V
EI=7.0kV/cm
Ehole=47.5kV/cm
0.4
0.2
0
0
0.05
0.1
0.15
Field Ratio (ED/Ehole)
0.2
0.25
・
Extraction Efficiency
Single GEM
EI dependence
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
100μmGEM
50μmGEM
・AAHEN
50mmGEM
100mmGEM
ΔVGEM=660V
ED=0.76kV/cm
Ehole=61.9kV/cm
0
0.05
0.1
0.15
Field Ratio (EI/Ehole)
測定
0.2
ΔVGEM=350V
ED=0.5kV/cm
Ehole=47.5kV/cm
0.25
Relative Gain
EI dependence
High Electric field
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
ED=0.75kV/cm
ΔVGEM=640V
ED=0.75kV/cm
ΔVGEM=660V
ED=0.75kV/cm
ΔVGEM=620V
0
1
2
3
4
5
6
7
8
9
10
11
12
13
Electric field (kV/cm)
Double GEM Test Chamber
0.75kV/cm
ET
7.0kV/cm
Drift
2.0 mm
Transfer
2.0 mm
Induction
2.0 mm
Relative Gain
Double GEM, 100μm
ET dependence
1.2
ArCO2
1
0.8
0.6
0.4
ΔVGEM=500V
ED=0.75kV/cm
EI=7.0kV/cm
0.2
0
0
0.5
1
1.5
2
2.5
3
Et[kV/cm]
Gain
高Gainを得たい
Double GEM
ΔVGEM We were not able to apply
the high voltage to ΔVGEM
100000
P10
P10[抵抗あり]
Ar-CO2(70-30)
10000
Ar-CO2(70-30)
[抵抗あり]
1000
100
380
430
480
530
580
ΔVGEM[V/cm]
Now
• Electric field @ Hole center
– 100μmGEM:61.9kV/cm (Maxwell 3D)
– 50μmGEM:47.5kV/cm (Maxwell 3D)
• Single GEM Max high Voltage→Δ VGEM:660V
• Double GEM Max high Voltage→ Δ VGEM:540V
– It is easy to discharge in Double GEM.
• The second layer GEM discharges due to large number of
electrons produced at the First layer GEM
We change a diameter of GEM hole.
70μmφ→90μmφ
Drift Plate(Mesh)
2mm
100μGEM(90φ)
2mm
Single GEM
ΔVGEM
10000
70Φ
90φ
70φ
ED=1.5kV/cm
EI=6.0kV/cm
Ehole=61.9kV/cm
Gain
1000
90Φ
ED=1.5kV/cm
EI=6.0kV/cm
Ehole=58.0kV/cm
100
10
500
550
600
650
ΔVgem[V]
700
750
800
ED dependence
90Φ VS 70Φ
Collection Efficiency
1.2
1
70Φ
ΔVGEM=660V
EI=6.0kV/cm
Ehole=61.9kV/cm
0.8
0.6
90Φ
0.4
ΔVGEM=660V
EI=6.0kV/cm
Ehole=58.0kV/cm
70Φ
90Φ
0.2
0
0
0.02
0.04
0.06
Field Ratio (ED/Ehole)
0.08
0.1
EI dependence
90Φ VS 70Φ
Extraction Efficiency
1.4
1.2
70Φ
1
ΔVGEM=660V
ED=0.76kV/cm
Ehole=61.9kV/cm
0.8
0.6
90Φ
0.4
ΔVGEM=660V
ED=0.76kV/cm
Ehole=58.0kV/cm
70Φ
90Φ
0.2
0
0
0.05
0.1
Field Ratio (EI/Ehole)
0.15
0.2
Summary
• 100μmGEM
– We have measured the basic characteristic.
• A Higher Gain can be got with 100 mm-Single GEM than
that with 50 mm-Double GEM . But the gain is not so high
as that with 50 mm-Triple GEM
– A diameter of a GEM hole.
• We changed a diameter of a GEM hole to 90μm φ from
70μm φ
– We can apply higher ΔVGEM .
– We can get 2times larger gain.
• Electric field @ Hole center
– 70μmφ:61.9kV/cm
– 90μmφ:58.0kV/cm
Recycle GEM
• We try to revitalize the GEM which discharges.
There is burnt
area
Normal
Zoom
Dead GEM
Damaged
東海電子工業株式会社の方で
エッジングを行った。
Soft etching
1~3%の塩酸
水溶液に浸ける
エッジング
マシン
80℃で6時間
乾燥
50cm/分のスピードでエッジングされる
Reprocessing
• Soft etching
– Etching time is shorter than usual chemical etching.
• Plasma etching
– An etching effect is stronger than chemical etching.
– Dead GEMs, which can not be recovered by soft
etching , are regenerated by Plasma etching.
Recovery of GEM is basically possible
About 90% of Dead GEMs can be recovered
by Soft or Plasma etching .
10000
1000
100
こちらを見てください
10
250
300
350
400
450
500
ΔVgem
550
600
650
700
750
ED dependence
90Φ VS 70Φ
1.2
1.1
Relative Gain
1
0.9
90φ
70φ
0.8
ΔVgem=660V
Ei=6.0kv/cm
0.7
0.6
0
0.5
1
1.5
2
Ed[kV/cm]
2.5
3
3.5
4
EI dependence
90Φ ,V,S 70Φ
1.4
1.2
90φ
70φ
Relative Gain
1
0.8
0.6
Ed=1.5kv/cm
ΔVgem=660V
0.4
0.2
0
0
1
2
3
4
5
Ei[kV/cm]
6
7
8
9
10
ED
Collection Efficiency
1.2
100μGEM
50μGEM
1
0.8
0.6
100mmGEM
ΔVGEM=660V
EI=6.0kV/cm
Ehole=61.9kV/cm
0.4
0.2
50mmGEM
ΔVGEM=350V
EI=7.0kV/cm
Ehole=47.5kV/cm
0
0
0.02
0.04
0.06
Field Ratio (ED/Ehole)
0.08
0.1
EI
1.8
1.6
100μmGEM
50μmGEM
1.4
1.2
1
0.8
0.6
0.4
0.2
0
0
0.05
0.1
0.15
0.2
0.25
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100μm厚GEMの基本特性 - SAGA-HEP