basic characteristic of １００ μ ｍＧＥＭ k,kadomatsu （ saga.u)...

Basic characteristic of１００ μ ｍＧＥＭ

　 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

• To understand a basic characteristic of 100 mGEM.

• We inspect that 100 mGEM can provide higher gain than 50 mGEM.

We want to get high gain

GEM Foil

140 μm

φ = 70μm

50 μm

5 μm

5 μm

CuPolyimide

10cm

10cm

Scienergy Co., Ltd. 製100μm

8 μm

8 μm

CuPolyimide

100m-GEM1

Drift Plate

2 ｍｍ

ED=0.75kv/cmEI=7kv/cm

Single 100mm-GEM Test Chamber

2 ｍｍ

Drift Area→ED

Induction Area →EI

GASAr-CO2(70/30)

2200pF

2200pF

Read out

Read out

55Fe (5.9 keV X-ray)

PCB

1mm

□15mm×15mm

36 ＝ 6×6

PCB

10

100

1000

10000

250 275 300 325 350 375 400

Δ Vgem/ 2　 (100μ )　　　=　　Δ Vgem　 50μ [V]（）

Gain

100μ (single)ｍ

50μ (triple)ｍ

We normalize ΔVGEM of 100μmGEM to Δ VGEM of 50μmGEM

Higher Gain is obtained with 100μmGEM

もう少し、高い電圧を掛けれるようにしたい

Single GEM Δ ＶＧＥＭ

Single GEMED dependence

0

0.2

0.4

0.6

0.8

1

1.2

0 0.05 0.1 0.15 0.2 0.25

Field　Ratio　(ED/ Ehole)

Collection　Effi

ciency 100μ GEM

50μ GEMΔVGEM=660VEI=6.0kV/cmEhole=61.9kV/cm

ΔVGEM=660VEI=6.0kV/cmEhole=61.9kV/cm

100mGEM



50mGEM

・　・・

・

Single GEM EI dependence

00.20.40.60.81

1.21.41.61.8

0 0.05 0.1 0.15 0.2 0.25

Field　Ratio　(EI/ Ehole)

Extraction　Effi

ciency

100μ mGEM50μ mGEM

ΔVGEM=660VED=0.76kV/cmEhole=61.9kV/cm


100mGEM



50mGEM

・　・・

00.20.40.60.81

1.21.41.61.82

0 1 2 3 4 5 6 7 8 9 10 11 12 13

Electric　field　(kV/ cm)

Relative　Gain

EI dependence 　High Electric field

ED=0.75kV/cm

ΔVGEM=640V

ED=0.75kV/cm

ΔVGEM=640V

ED=0.75kV/cm

ΔVGEM=620V

ED=0.75kV/cm

ΔVGEM=620V

ED=0.75kV/cm

ΔVGEM=660V

ED=0.75kV/cm

ΔVGEM=660V

Double GEM Test Chamber

2.0 mm

2.0 mm

2.0 mm

Induction

Drift

Transfer

7.0kV/cm

0.75kV/cm

ET

Double GEM, 100μm ET dependence

0

0.2

0.4

0.6

0.8

1

1.2

0 0.5 1 1.5 2 2.5 3Et[kV/ cm]

Relative　Gain

ArCO2

0

0.2

0.4

0.6

0.8

1

1.2

0 0.5 1 1.5 2 2.5 3

ΔVGEM=500VED=0.75kV/cmEI=7.0kV/cm

ΔVGEM=500VED=0.75kV/cmEI=7.0kV/cm

Double GEMΔV ＧＥＭ

100

1000

10000

100000

380 430 480 530 580

Δ ＶＧＥＭ[V/ cm]

Gain

P10

P10[ ]抵抗あり

Ar-CO2(70-30)

Ar-CO2(70-30)[ ]抵抗あり

We were not able to apply the high voltage to ΔVGEM

高 Gain を得たい

Now

• Electric field @ Hole center– １００ μ ｍＧＥＭ：６１．９ kV/cm (Maxwell 3

D)– ５０ μ ｍＧＥＭ：４７．５ kV/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.

70μ ｍ φ→ ９０ μ ｍ φ

100μGEM （ 90φ ）

Drift Plate （ Mesh ）

２ｍｍ

２ｍｍ

Single GEM Δ ＶＧＥＭ

10

100

1000

10000

500 550 600 650 700 750 800

Δ Vgem[V]

Gain

90φ70φ

ED=1.5kV/cmEI=6.0kV/cmEhole=61.9kV/cm


70Φ



90Φ

0

0.2

0.4

0.6

0.8

1

1.2

0 0.02 0.04 0.06 0.08 0.1


Collection　Effi

ciency

70Φ90Φ

ED dependence90Φ VS 70Φ



70Φ



90Φ

0

0.2

0.4

0.6

0.8

1

1.2

1.4

0 0.05 0.1 0.15 0.2

Field　Ratio　(EI/ Ehole)

Extraction　Effi

ciency

70Φ90Φ

EI dependence90Φ VS 70Φ



70Φ



90Φ

Summary• 100μmGEM

– We have measured the basic characteristic.• A Higher Gain can be got with 100 m-Single GEM than t

hat with 50 m-Double GEM . But the gain is not so high as that with 50 m-Triple GEM

– A diameter of a GEM hole.• We changed a diameter of a GEM hole to 90μm φ from 70

μm φ– We can apply higher ΔVGEM .– We can get 2times larger gain.

• Electric field @ Hole center– ７０ μ ｍ φ ：６１．９ kV/cm– ９０ μ ｍ φ ：５８．０ kV/cm

Recycle GEM

• We try to revitalize the GEM which discharges.

Dead GEM　

Normal

Damaged

There is burnt area

Zoom

Soft etching１～３％の塩酸水溶液に浸ける

５０ｃｍ /分のスピードでエッジングされる

エッジングマシン

８０℃で６時間　　　乾燥

東海電子工業株式会社の方でエッジングを行った。

http://www.arttodayjapan.com/

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 etchin

g , 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

10

250 　　 300 350 400 450 500 550 600 650 700 750

ΔVgem

こちらを見てください

0.6

0.7

0.8

0.9

1

1.1

1.2

0 0.5 1 1.5 2 2.5 3 3.5 4

Ed[kV/ cm]

Relative　Gain

90φ70φ

ΔVgem=660VEi=6.0kv/cm

ED dependence90Φ VS 70Φ

0

0.2

0.4

0.6

0.8

1

1.2

1.4

0 1 2 3 4 5 6 7 8 9 10

Ei[kV/ cm]

Relative　Gain

90φ70φ

Ed=1.5kv/cmΔVgem=660V

EI dependence90Φ ,V,S 70Φ

0

0.2

0.4

0.6

0.8

1

1.2

0 0.02 0.04 0.06 0.08 0.1


Collection　Effi

ciency

100μ GEM50μ GEM

ＥＤ



100mGEM



50mGEM

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

0 0.05 0.1 0.15 0.2 0.25

100μ mGEM50μ mGEM

ＥＩ

basic characteristic of １００ μ ｍＧＥＭ k,kadomatsu （ saga.u)...

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