The work of GEM foil at CIAEThe 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

outlineoutline

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 1Part 1 ：： MotivationMotivation

JLab 12GeV UpgradeJLab 12GeV Upgrade

New Hall

Add arc

Enhanced capabilitiesin existing Halls

Add 5 cryomodules

Add 5 cryomodules

20 cryomodules

20 cryomodules

SoLID spectrometerSoLID spectrometer

Transversity

PVDIS

longitudinal

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

Part 2: The Structure of GEM Foil

GEM (Gas Electron Multiplier) StructureGEM (Gas Electron Multiplier) Structure

Structure of detector with single GEM foil

Ar+CO2

1.1. Avalanche Gaseous Avalanche Gaseous DetectorDetector

2.2. Core part: GEM FoilCore part: GEM Foil

3.3. Sealed by the Sealed by the window and the window and the substrate to form a substrate to form a pressure-tight pressure-tight gaseous chambergaseous chamber

GEM (Gas Electron Multiplier) StructureGEM (Gas Electron Multiplier) Structure

Structure of detector with triple GEM foils

Ar+CO2

GEM Foil StructureGEM Foil Structure

A sandwich structure

5-10μm copper foils on the surfaces of Kapton foils

GEM Foil GEM Foil Structure 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

Kapton foils have excellent mechanical, physical and chemical properties. They will not melt, burn, and they are flexible.

Field shape of a GEM foil

Process Process FFlow low DDiagram of GEM iagram of GEM MManufactureanufacture

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

From From FFoils to oils to DDetectorsetectors

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 outRead 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 CERNAgreement 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 GEM FFoil oil from CERNfrom CERN

10cm*10cm GEM foil sample

GEM Mask Plate from CERN

10cm*10cm mask plate

GEM GEM FFoil oil Researches Researches at CIAEat CIAE1. 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

Mask PlateMask Plate MMade in Chinaade in China

5cm*5cm mask plate

Nuclear Pore Foil Production at CIAEat 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

CleanroomCleanroom

our 1K level cleanroom for

etching ， framing ， cleaning and

PART 4PART 4 ： ： Thick-GEM (THGEM) detectoThick-GEM (THGEM) detectorr

Introduction of Introduction of Thick-GEM (THGEM) detectorThick-GEM (THGEM) detector

A. Breskin, M. Cortesi, R. Alon, J. Miyamoto & R. Chechik

Weizmann institute of science, Rehovot, Israel

EHole

EHole

ETran

EInd

EDrift

radiation

e-s

Readout anode

Difference Between GEM and THGEM FoilsDifference Between GEM and THGEM Foils

Typical parameters:• 50m Kapton• metal coated• Ø70m holes• 100-200m pitch

GEM TH-GEM

Manufactured by standard PCB techniques of precise drilling in G-10 (and other materials) and Cu etching.

Some Results of THGEM from BreskinSome Results of THGEM from Breskin

THGEM - Gain vs rim sizeTHGEM - Gain vs rim size

0.04 0.06 0.08 0.10 0.12102

103

104

105

Gai

n

Rim size (mm)

Ar/CH4 (95:5)

atm press

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

Double-THGEM6 keV x-rays

104

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

VHOLE [Volt]

single electronsSingle THGEM Gain 104-105 Double THGEMs gain 106-107

THGEM Foil Made in ChinaTHGEM Foil Made in China

THGEM from Breskin

• Drills with milling cutter

• 40-120 m rims

THGEM from IHEP•No such technology manufactories•Copper etching

Thick-GEM Test at IHEPThick-GEM Test at IHEP

0.2mm diameter THGEM according to CIAE requirement

Test of 0.2mm Diameter THGEM

sdfsdfwe lost some gainwe lost some gain ，，

but we save lots of but we save lots of moneymoney ！！cheapcheap （（ ~200 ~200 doller/mdoller/m22 ））

breakdown won't damage the THGEM foil or electronicsbreakdown won't damage the THGEM foil or electronics

Thick-GEM Test ResultThick-GEM Test Result

Thick-GEM Test ResultThick-GEM Test Result

Energy resolution is about20%

Thick-GEM Test ResultThick-GEM Test Result

stable in 24 hours

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 efficiencydetection efficiency lower

spatial resolution 70μ estimate limit value is 300μm

Part 5 ： Next step

• Copper etching

• Make read-out strips RPC manufacture （ see Shouyang HU’s talk ）• Use APV25 electronic test GEM spatial res

olutions• Make and test GEM and THGEM detectors

using the foils made in China

Thank you ！