1. The work of GEM foil at CIAE
Li Ye, Xiaomei Li
Science and Technology
on Nuclear Data Laboratory
China Institute of Atomic Energy
weihai

2. outline 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

3. Part 1：Motivation

4. Enhanced capabilities
JLab 12GeV Upgrade
New Hall
Add arc
Enhanced capabilities
in existing Halls
Add 5 cryomodules
20 cryomodules

5. SoLID spectrometer Transversity PVDIS longitudinal
CIAE，USTC，TSinghua，Peking，HUST，Shandong，Lanzhou，Huangshan，and so on 5

6. CIAE，USTC，TSinghua，Peking，HUST，Shandong，Lanzhou，Huangshan，and so on

7. Part 2: The Structure of GEM Foil

8. GEM (Gas Electron Multiplier) Structure
Avalanche Gaseous Detector
Core part: GEM Foil
Sealed by the window and the substrate to form a pressure-tight gaseous chamber
Ar+CO2
Structure of detector with single GEM foil

9. GEM (Gas Electron Multiplier) Structure
Ar+CO2
Magnify carbon dioxide
Structure of detector with triple GEM foils

10. GEM Foil Structure A sandwich structure
5-10μm copper foils on the surfaces of Kapton foils

11. GEM Foil Structure
A dipole field will form when a voltage is applied on the two sides of the foil, gathering the field lines between the drift electrode and read-out electrode into holes.
Avalanche happens in holes
Field shape of a GEM foil
Kapton foils have excellent mechanical, physical and chemical properties. They will not melt, burn, and they are flexible.

12. Process Flow Diagram of GEM Manufacture
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.
b Make 5-10μm copper foils on the surfaces of Kapton foils by vacuum deposition technique.
2.Photoresist coating.
Pull the Kapton foil out of 303 negative photoresist, the thickness can be controlled by the pulling-out speed.
3.Lithography
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.
processes

13. From Foils to Detectors
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
Epoxy
Dry and solidify
A standard GEM foil

14. Read out
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.
CMOS.
CCD.

15. Part 3：GEM Foil Researches at CIAE

16. Agreement with CERN
Prof. Xiaomei LI has visited CERN PCB factory and GEM group in Feb
We got two GEM foil samples and two mask plates from CERN.
CERN PCB factory has agreed that 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.
So we can say that the technique route has no problem 16

17. GEM Foil from CERN
10cm*10cm GEM foil sample

18. GEM Mask Plate from CERN
10cm*10cm mask plate

19. GEM Foil Researches at CIAE
1. Kapton foil covered with copper
has got from the manufacturer in
china.
2. Photoresist coating and masking
Cooperate with the factory, we can
make 70μm diameter 5cm* 5cm
mask plate
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
experience.
5. Clean room for GEM construction
GEM Foil Researches at CIAE

20. Mask Plate Made in China
5cm*5cm mask plate

21. Nuclear Pore Foil Production at CIAE
HI-13 accelerator
particles are accelerated by HI-13 then pass through the kapton foil，kapton etching，20um，control the hole size by etching time

22. Cleanroom
our 1K level cleanroom for
etching，framing，cleaning and

23. PART 4： Thick-GEM (THGEM) detector

24. Introduction of Thick-GEM (THGEM) detector
A. Breskin, M. Cortesi, R. Alon, J. Miyamoto & R. Chechik
Weizmann institute of science, Rehovot, Israel
EHole
ETran
EInd
EDrift
radiation
e-s
Readout anode

25. Difference Between GEM and THGEM Foils
Typical parameters:
50mm Kapton
metal coated
Ø70mm holes
mm pitch
Manufactured by standard PCB techniques of precise drilling in G-10 (and other materials) and Cu etching.

26. Some Results of THGEM from Breskin
single electrons
Single THGEM Gain
Double THGEMs gain
THGEM - Gain vs rim size
Double-THGEM
6 keV x-rays
VHOLE [Volt]
104
pitch = 1 mm; diameter = 0.5 mm;
rim=40; 60; 80; 100; 120 mm
Recent Advances in Thick-GEM(THGEM) Detectors -Feb A. Breskin

27. THGEM Foil Made in China
THGEM from Breskin
Drills with milling cutter
mm rims
THGEM from IHEP
No such technology manufactories
Copper etching

28. Thick-GEM Test at IHEP
0.2mm diameter THGEM according to CIAE requirement

29. Test of 0.2mm Diameter THGEM

30. we lost some gain，but we save lots of money！ cheap（~200 doller/m2）
Thick-GEM Test Result
sdf
we lost some gain，but we save lots of money！ cheap（~200 doller/m2）
breakdown won't damage the THGEM foil or electronics

31. Thick-GEM Test Result
Energy resolution is about20%

32. Thick-GEM Test Result
stable in 24 hours
stability

33. Compare with GEM detector
GEM THGEM
some technical difficulties most PCB factories can make
high cleanliness requirements you can put in your pocket
easily damaged durable
expensive cheap
high detection efficiency lower
spatial resolution 70μ estimate limit value is 300μm

34. Part 5：Next step Copper etching 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

35. Thank you ！