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 Part 4: THGEM detector and test at IHEP Part 5

：

Next step

Part 1

：

Motivation

JLab 12GeV Upgrade

New Hall 20 cryomodules Add arc Add 5 cryomodules Add 5 cryomodules 20 cryomodules Enhanced capabilities in existing Halls

Transversity PVDIS longitudinal

SoLID spectrometer

CIAE

，

USTC

，

TSinghua

，

Peking

，

HUST

，

Shandong

，

Lanzhou

，

Huangshan

，

and so on

Part 2: The Structure of GEM Foil

GEM (Gas Electron Multiplier) Structure

1. Avalanche Gaseous Detector 2. Core part: GEM Foil 3. Sealed by the window and the substrate to form a pressure-tight gaseous chamber Ar+CO 2 Structure of detector with single GEM foil

GEM (Gas Electron Multiplier) Structure

Ar+CO 2 Structure of detector with triple GEM foils

GEM Foil Structure

A sandwich structure 5-10μm copper foils on the surfaces of Kapton foils

GEM Foil Structure

1. 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.

2. 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.

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 etching time.

（ 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 5. Kapton foil etching The most important step of the whole process flow diagram.

processes

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

Read out

Electrodes collecting avalanche electrons have crucial effects on spatial resolution, time resolution and detection efficiency.

Principle of Read Out 1. Parallel Strips and Pads Array 2. Thin Film Transistor, TFT.

3. CMOS.

4. CCD.

Part 3

：

GEM Foil Researches at CIAE

Agreement with CERN

•

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 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.

GEM Foil from CERN

10cm*10cm GEM foil sample

GEM Mask Plate from CERN

10cm*10cm mask plate

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 70

μm

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

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

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

Cleanroom our 1K level cleanroom for etching

，

framing

，

cleaning and

PART 4

：

Thick-GEM (THGEM) detector

Introduction of Thick-GEM (THGEM) detector A. Breskin , M. Cortesi, R. Alon, J. Miyamoto & R. Chechik

Weizmann institute of science, Rehovot, Israel

radiation E Drift E Hole E Tran E Hole E Ind e s

Readout anode

Difference Between GEM and THGEM Foils

GEM TH-GEM Typical parameters: • 50 m m Kapton • metal coated • Ø70 m m holes • 100-200 m m pitch Manufactured by

standard PCB techniques

of precise drilling in G-10 (and other materials) and Cu etching.

Some Results of THGEM from Breskin

THGEM - Gain vs rim size 10 5 Double-THGEM 6 keV x-rays

10 4

10 4

single electrons

Single THGEM Gain

10 4 -10 5

Double THGEMs gain

10 6 -10 7

10 3 Ar/CH 4 (95:5) atm press 10 2 0.04

0.06

0.08

0.10

Rim size (mm) 0.12

pitch = 1 mm; diameter = 0.5 mm; rim=40; 60; 80; 100; 120

m

m

V HOLE [Volt]

Recent Advances in Thick-GEM(THGEM) Detectors -Feb.2008 A. Breskin

THGEM Foil Made in China

• • THGEM from Breskin Drills with milling cutter 40-120 m m rims THGEM from IHEP •No such technology manufactories •Copper etching

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

Test of 0.2mm Diameter THGEM

we lost some gain ， but we save lots of

money

！

Thick-GEM Test Result

sdf

cheap

（

~200 doller/m 2

）

breakdown won't damage the THGEM foil or electronics

Thick-GEM Test Result Energy resolution is about20%

stable in 24 hours Thick-GEM Test Result stability

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

spatial resolution 70 μ lower estimate limit value is 300 μm

Part 5

：

Next step

• • • •

Copper etching Make read-out strips RPC manufacture

（

see Shouyang HU

’

s talk

）

Use APV25 electronic resolutions test GEM spatial Make and test GEM and THGEM detectors using the foils made in China

Thank you

！