The work of GEM foil at CIAE. Li Ye, Xiaomei Li Science and Technology on Nuclear Data Laboratory China Institute of Atomic Energy 2011.08 weihai. outline. Patr 1: Motivation Part 2: The structure of GEM foil Part 3： Gem foil researches at CIAE
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The work of GEM foil at CIAE
Li Ye, Xiaomei Li
Science and Technology
on Nuclear Data Laboratory
China Institute of Atomic Energy
Patr 1: Motivation
Part 2: The structure of GEM foil
Part 3：Gem foil researches at CIAE
Part 4: THGEM detector and test at IHEP
Part 5： Next step
Add 5 cryomodules
Add 5 cryomodules
in existing Halls
CIAE，USTC，TSinghua，Peking，HUST，Shandong，Lanzhou，Huangshan，and so on
Part 2: The Structure of GEM Foil
Structure of detector with single GEM foil
Structure of detector with triple GEM foils
A sandwich structure
5-10μm copper foils on the surfaces of Kapton foils
Field shape of a GEM foil
Kapton foils have excellent mechanical, physical and chemical properties. They will not melt, burn, and they are flexible.
1. Copper-plating on the two sides of Kapton foils.
a Clad the 5-10μm copper foils on the surfaces of Kapton foils by hot-pressing.
bMake 5-10μm copper foils on the surfaces of Kapton foils by vacuum deposition technique.
Pull the Kapton foil out of 303 negative photoresist, the thickness can be controlled by the pulling-out speed.
The patterns on the mask can be transferred to the photoresist layer, then wash it with developing solution.
4.Copper foil etching
Washing the foil with 30% iron trichloride（FeCl3）solution, then the pattern on the photoresist layer can be transferred to the copper foil layer, the depth of etching can be controlled by controlling the etching time.
5. Kapton foil etching
The most important step of the whole process flow diagram.
GEM foil is flexible, it must be fixed by a frame, then it can be mounted on detectors.
Processes of Fixation
Fix by a fiberglass substrate
Dry in 40°C circumstances
Dry and solidify
A standard GEM foil
Electrodes collecting avalanche electrons have crucial effects on spatial resolution, time resolution and detection efficiency.
Principle of Read Out
Parallel Strips and Pads Array
Thin Film Transistor, TFT.
Part 3：GEM FoilResearches at CIAE
Prof. Xiaomei LI has visited CERN PCB factory and GEM group in Feb. 2011 .
We got two GEM foil samples and two mask plates from CERN.
CERN PCB factory has agreedthat they would transfer the GEM foil production technology to CIAE for free for the research of high energy physics. Now we are doing the paper work.
10cm*10cm GEM foil sample
10cm*10cm mask plate
1. Kapton foil covered with copper
has got from the manufacturer in
2. Photoresist coating and masking
Cooperate with the factory, we can
make 70μm diameter 5cm* 5cm
3. Copper etching ---some problems.
It will be solved after getting the
technology transfer from CERN.
4. Kapton etching
CIAE has over 20 years nuclear pore
foil production and kapton etching
5. Clean room for GEMconstruction
5cm*5cm mask plate
particles are accelerated by HI-13 then pass through the kapton foil，kapton etching，20um，control the hole size by etching time
our 1K level cleanroom for
PART 4： Thick-GEM (THGEM) detector
A. Breskin, M. Cortesi, R. Alon, J. Miyamoto & R. Chechik
Weizmann institute of science, Rehovot, Israel
Manufactured by standard PCB techniques of precise drilling in G-10 (and other materials) and Cu etching.
Single THGEM Gain 104-105
Double THGEMs gain 106-107
THGEM - Gain vs rim size
6 keV x-rays
pitch = 1 mm; diameter = 0.5 mm;
rim=40; 60; 80; 100; 120 mm
Recent Advances in Thick-GEM(THGEM) Detectors -Feb.2008 A. Breskin
THGEM from Breskin
Drills with milling cutter
40-120 mm rims
0.2mm diameter THGEM according to CIAE requirement
Thick-GEM Test Result
we lost some gain，but we save lots of money！cheap（~200 doller/m2）
breakdown won't damage the THGEM foil or electronics
Energy resolution is about20%
stable in 24 hours
some technical difficulties most PCB factories can make
high cleanliness requirements you can put in your pocket
easily damaged durable
high detection efficiency lower
spatial resolution 70μ estimate limit value is 300μm
Make read-out strips
RPC manufacture（see Shouyang HU’s talk）
Use APV25 electronic test GEM spatial resolutions
Make and test GEM and THGEM detectors using the foils made in China
Thank you ！