Recent R&D workon Micromegas detector Recent R&D work on Micromegas detector Liang Guan University of Science and Technology of China April,2010 @ NanChang

Recent R&D workRecent R&D work on Micromegas detectoron Micromegas detector

Liang Guan

University of Science and Technology of China

April,2010 @ NanChang University

Center for particle physics and technology

Joint Laboratory of Technologies of Particle Detection and Electronics

April,2010 NanChang University 1

OutlineOutline

Introduction

Simulation

Prototypes fabrication

Test Results

Summary

Liang Guan


Introduction

Liang Guan

3April,2010 NanChang University

Traditional Gaseous detector MWPC faces problems:

• Rate capability restrained by space charge effect

• Spatial resolution limited by wire pitch

Micromegas (Micro Mesh gaseous structure)

Invented in1996 by Y. Giomataris et al,CEA Saclay, France

Nuclear Instruments and Methods in Physics Research A 376 (1996)

Development of Micromegas

Micromegas Working principle

Liang Guan


Development of Micromegas

high rate capability > 108 mm-2s-1

space resolution ~m

energy resolution

time resolution

radiation hardness

simple structureY. Giomatarisa NIM A 419 (1998)

J. Derre& et al. NIM A 459 (2001) Leszek Ropelewski (CERN) et al.94th LHCC Committee Meeting, July 2 2008

A. Delbart et al. NIM A 461 (2001)

Liang Guan


Introduction: Application of Micromegas

COMPASS CAST

40cm*40cm 7cm*7cm

NA48/KABES beam spectrometer The T2K ND-280 TPC

Future application: ILC TPC, LHC upgrade, Neutron detection…

34 cm x 36 cm

Liang Guan


Simulation

Liang Guan


de Broglie wavelength of electron can be compared with the radius of noble gas atom undergo a phase shift when passing through the strong attractive field around the atom and results in low interaction cross-section, long mean free path

~0.24eV

• Ramsauer Dip in Argon+Isobutane • Electron thermic energy

Gas Properties

Ar 90 <- 95

Ar 100%

Ar/iC4H10 90/10

Magboltz

Ar/iC4H10 96/4

Liang Guan


Gas Properties

Ar90% Iso10%

• Drift velocityMagboltz

Liang Guan

April,2010 NanChang University

Gas Properties

• Excitation rate & Penning transfer 1 atm Pressure

Argon: 15.7eVIsobutane: 10.67eV

Magboltz

Liang Guan 9


Field, Drift, ionization

[Drift Gap:3mm, Avalanche Gap:120mm, Vava= -500V, field ratio 200]

R-T relationElectron drift velocity

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Signal

Pad 1 Pad 2 Pad 3 Pad 4 Pad 5

Signal on 5 readout pads

5.9 keV x-ray

• Track, cluster, drift lines • Weighting field

N

nnn

N

nnn VQVQ

11

Reciprocity theorem

Ramo theorem

ww V

txq

V

VqQ

)]([01

Pad 1

Ar/iC4H10 90/10

Vmesh=400

Field ratio 200

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250m 100m


Prototypes

Liang Guan


Review

Different materials

mesh: grid by chemical etching, electroformed … (stainless steel, copper, nickel, gold… )

woven wires (nickel, copper, stainless steel)

spacer: quartz fibers, pillars by photo-lithography (mainly used), Kapton ring, fishing line…

Different technologies

Bulk MicrobulkStandard lithography and kapton etching

InGrid Lithography & woven mesh CMOS compatible InGrid technology

Liang Guan


Thermo-bond film

An novel idea to construct amplification gap in Micromegas: use Thermo-bond film

Thermo-bond film adhesive bonding film, flexible & insulating usually made of a substrate sandwiched by two bond lines or only two bond lines attached together side by side solid at room temperature, melt & becomes adhesive after heat is applied.

Features various thickness: 80m,125m,155m,160m… good mechanical property: tensile strength@break--several thousand psi softening temperature 100-200℃ dielectric property: dielectric constant ~2.4, volume resistivity>1017ohm/mil excellent metal adhesion uniform adhesive thickness

Proposed by Prof. T.C. Zhao

Liang Guan


Thermo-bond film

Motivation and prospects

• Possible to use such kind of film to build detector without internal solid state support structure

No internal dead area

Nuclear medical imaging

• Possible to make detector with large sensitive area

• Possible to make multi-layer parallel mesh chamber

• Quick, Easy fabrication, Economical

The detection of low cross-section or rare processes (dark matter, double beta decay…)

Liang Guan


Prototype Fabrication

350LPI mesh

Mesh stretching

Thermal attaching

sensitive area: 45mm*45mmThermo-bond film thickness: 155mm (width for each side:7mm), also tried other films…Avalanche, drift mesh: 350LPI woven wire mesh Drift region: 9mmAvalanche region thickness: 130mm Readout: 9 Pads(15mm*15mm) connected in parallel

Drift electrode

“Bulk” avalanche region

Frame Assembling

Liang Guan


Experimental Setup

Drift mesh -HV

Avalanche mesh -HV

Readout Pad

Ortec142AH

Ortec 855 spectroscopy amplifier

MCA

ComputerHV

Supplier

55Fe

Gas input

Gas output

R

Sketch map of testing system Electronic calibration

Pulse: rise time<10ns ,duration>100s,Period>3ms

Calibration for 10 times Head amp.

Pulse

Liang Guan


Test Results

Liang Guan


HV Plateau & Counting rate

Test at Ar96% Iso4% gas mixture, MCA cut:150th channel, test time: 100s Test at Ar96% Iso4% gas mixture, Vmesh=400, Vdrift=613, Head Amp=20

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Electron transparency

Ar80 Ar90 Ar94 Ar95

Liang Guan

By Guo Junjun * For high field ratio-> Diffusion, attachment in drift region

Field ratio: Eava/Edrift

21

Gas Gain

Energy linearity

Gain as a function of mesh HV

155m

Gas gain of more than2*104 has been achieved

0N

NG

N: electron # collected at the anode

N0: # of electrons generated in the conversion (drift) gap by 5.9KeV

Electron transparency (assume 100% for 350LPI mesh)

Liang Guan


1.109(Exp)

13.7% (FWHM)

Photo-peak ratio:

1.102(Theory)

Best energy resolution

K

Energy resolution for 5.9 keV x-ray can be better than 20% over one order of magnitude in gain

Deterioration of energy resolution for argon-rich gas mixture: influence of polyatomic molecular

Energy resolution

S. Behrends and A.C. Melissinos, NIM A 1889 (1981)

Liang Guan


Summary

Simulation study: Ramsauer Dip in Argon/iC4H10, penning transfer etc.

A novel idea: use thermo-bond films to separate avalanche mesh from anode plane.

Gas Gain>3.7*104, Energy resolution better than 13.7%.

Continues efforts should be made to systemically study performances of detectors with other films. Also try to make large size prototypes.

Liang Guan

Thank you !


Back up

Liang Guan

Penning transfer

Penning transfer---sim &exp

Gas comp. Ar* (%)

Ar+Iso5 35.03

Ar+Iso6 35.22

Ar+Iso7 35.91

Ar+Iso8 37.84

Ar+Iso9 38.03

Ar+Iso10 38.67

* Higher Isobutane concentration lead to higher penning transfer prob.

Penning transfer

Where penning transfer start

Ar+Iso10% (38% Ar*)

Ar+Iso10%

Ar+Iso20% (40% Ar*)

Ar+Iso20%Where penning transfer start


Back up

Liang Guan

Mesh Wire diameter (m)

Hole size (m)

350LPI (tabby) 24 47.2-48.2

400LPI (tabby) 21.7 40.5-41.1

400LPI (diagonal) 26.4 34.2-36.4

500LPI (diagonal) 21.7 27.7-29.9

Mesh parameters


Back up

signal

Liang Guan

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Recent R&D workon Micromegas detector Recent R&D work on Micromegas detector Liang Guan University of Science and Technology of China April,2010 @ NanChang