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July-05-2013

GEM R&D Activity in USTC

Yi Zhou

University of Science & Technology of China

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Outline

The NS2 Self-stretching Technique

The 30cm×30cm GEM of USTC

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The self-stretching technique

Readout PCB

Readout PCB

GEMs

GEMs

Drift

Drift

NS1 is relaying on the elastic properties of the periphery frame

The screw is pushing the frame before the stretching.

The screw is pulling out the console

Detector Base

Detector Base

NS1

NS2

L. Franconi, A. Marinov, R. De Oliveira Status of no-stretch no-spacer GEM assembly

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The advantages of NS2

The whole construct progress is driving the screws, it is very easy and very fast, so that we can assemble a detector in 2 hours；

All the GEM foils are self-stretched, the detector doesn’t need support frames anymore. It means that there is no dead area inside the detector, no glue aging and gas flow problems anymore；

All the screws can be released and tightened again, so that any part of the detector is replaceable, it means that the cost of the GEM project can be greatly decreased；

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3D model of NS2 GEM

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10M

RGEM1

RGEM2

RGEM3

10M

10M

10M

100k Drift

dI=2mm

dT2=2mm

dT1=2mm

dD=3mm

HV 100k100k100k100k100k

2.2nF2.2nF2.2nF2.2nF

Connection of HV divider & filter

RD=1M

RGEM1=0.55M

RT1=1M

RGEM2=0.5M

RT2=1M

RGEM3=0.45M

RI=1M

Low Pass Filter

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The temperature of the dividers

HV=4500V

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Inefficiency estimate

LCR Meter

Capacity of 10cm×10cm GEM foil: ~4.5nF

After each discharge, the GEM sector need recharge, if the protected resistor is 10MΩ, the recharge time is about:

T = 4.5nF × 10MΩ ≈ 45ms this 45ms charging time causes

the inefficiency.

If we require the inefficiency < 1%, we need P×Φ×S×T < 1% , we have:

Here: P: the discharge probability; Φ: the flux of the beam; S: the area of a GEM sector; T: the recharge time(~45ms)

%1SP

T

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Foil assemblage

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Gas tight test

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Detector assemblage

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HV discharge problem & solution

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GEM system

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Signal of 30cm×30cm GEM from Rui

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We need the Cu-target X-ray tube

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Ultrasonic bath for detector clean

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Summary & near future work

System calibration for gain measurement; uniformity test for gain and energy resolution;

Setup the clean system;

The NS2 self-stretching technique is a very efficient way for the GEM detector construction; The HV part on the GEM detector should be sealed;

Summary:

Near future work: