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足付き GEM / GEM 付き micromegas. 佐賀大学 大学院工学系研究科物理学専攻 1年 青座 篤史. Good point of GEM. Good point of micromegas. Gain is large. Easy to handle. Danger of damaging RO electronics is a little. Diffusion at the gas amplification is small. Weak point of GEM. Weak point of micromegas. - PowerPoint PPT Presentation
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足付き GEM/ GEM付き micromegas
佐賀大学 大学院工学系研究科物理学専攻 1年青座 篤史
Good point of GEM
The frame becomes a dead space.
Good point of micromegas
•Diffusion at the gas amplification is large
•Gain is large
•Gain is small
Weak point of GEM Weak point of micromegas
•The frame is necessary
•discharge
Damage to RO electronics.
•Easy to handle
Multi-layer structure
•Diffusion at the gas amplification is small•Danger of damaging RO electronics is a little.
GEM+micromegas(足付き GEM)
•Structure to combine GEM with micromegas
GEM+micromegas
gas amplification area
•Gain is large
•The danger of the electrical discharge is reduced.
amplification areaThe amplification area is kept away from the reading part.
•The frame is unnecessary.
micromegas
Micromegas
Pad
•Operation test in airThere were a lot of electrical discharges in a low potential difference(250V~ 280V) .
50μm
Result of electric field calculation by Maxwell3D
•It is a high electric field in the place where the insulator is near Pad.
•The insulator should be vertical to Pad.
micromegas
setup
ED : 100[V/cm]
天板
Pad
Fe55 ( 5.9keV ) Pad
•3.01cmピッチ( Pad間隔 100μm)
足の形を円柱にしたメッシュの micromegasをテスト
Gas : P10 : 95 %、 C4H10 : 5 %
200μ m
50μ m
15μm
The same method as saclay group
Operation test of micromegas(mesh )
P10: 95%、 C4H10: 5%で 440Vまで印加でき、動作する事は確認できた。
GEM+micromegas(足付き GEM)
足付きGEM(サイエナジー社製)試作品
10 cm ×10cm
200μ m
50μ m
足の大きさ
Operation test
3 [cm ]
55Fe
Ed : 100[V/cm]ΔVGEM = 250[V]Pad~GEM :250[V]
Setup
Gas : P-10 ( Ar 90% 、 CH4 10% )
6mm
0.1mm 1.17mm
Pad
Operation test
1 2 3 4
It measures it by using six Pad.
Operation test
Setup
Pad
1mm
1.5cm
1.5cm
3 [cm ]
55Fe
Ed : 100[V/cm]ΔVGEM = 320[V]Pad~GEM : 190 ~240[V]
Gas : P-10 ( Ar 90% 、 CH4 10% )
Pad ~ GEM: 240VPad ~ GEM: 230VPad ~ GEM: 220V
Pad ~ GEM: 210VPad ~ GEM: 200VPad ~ GEM: 190V
55Fe
Ar : CH4=80: 20
Ar : CH4=70: 30
Ar : CH4=60: 40
Ar : CH4=50: 50
Ar : CH4=40: 60
Ar : CH4=30: 70
Ar : CH4=20: 80
The mixture ratio of the gas was changed.
Ar : CH4=0 :100
Ar : CH4=90: 10
Ar : CH4=95: 5
これまでの測定で使っていた足付き GEM もう 1枚の足付きGEM
resolution : 0.13 resolution : 0.10
Ed : 100[V/cm]ΔVGEM=320[V]Pad~GEM: 210[V]
Gas : P-10 ( Ar 90%、 CH4 10%)
•Result of measurement動作することは確認できたが、再現性がない。
Summary
•Gain is large was able to be confirmed.
•no reproducibility.
詳しくはまだ解っていないが、足付き GEMは micromegasに比べて構造が厚いため足付き GEMをフラットにするには静電力が十分ではないようで、空気中で印加した様子では、読み出し Padに張り付いてフラットになっているようには見えなかった。今後、この問題を改善したい。
Question concerning Garfield
ION FEEDBACKelectron ion
Avalanche
losses
Feedback
GEM GATE
ion
GATE 電子を通すときとは逆の電位差にしてイオンをここで止める。
Question concerning Garfield
GATE
electron
Q 1
Q 2
Q2/Q1ができるだけ 1に近くなるセットアップ( ΔVGEM、 hole、 GAS)を調べる
•Garfieldで電子をモンテカルロドリフト させて Q2/Q1を評価する。
step
•step size Interval when position of electron is updated
Step size is specified by the number of collisions and length.
Question concerning Garfield
•The calculations are stopped if the number of step reaches the maximum number of steps allowed
•It reaches the maximum number of steps before the particle reaches the electrode if the step size is too small.
•If the steps are too large, the method is inaccurate.
collection efficiency
extraction efficiency
1000
•length
Question concerning Garfield
extraction efficiencyextraction efficiency
collection efficiency collection efficiency
•Number of collisions
GAS EFFECT
P-5Ar‐CO 2 70-30
Measurement by Sauli
simulation
φ100μm
φ70μm
HOLE DIAMETER EFFECT
Measurement by Sauli
simulation
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