Micro Pattern Gas Detectors VCI- Vienna Conference on Instrumentation 2001 R.Bellazzini - INFN Pisa1...

Micro Pattern Gas Detectors

VCI- Vienna Conference on Instrumentation 2001 R.Bellazzini - INFN Pisa 1

Progress in Micro Pattern Gas Detectors

R. BellazziniINFN - sez. Pisa

Vienna Conference on Instrumentation 2001



Outline• Why are we interested in Micro Pattern Gas Detector?

• Performances and limitations• Solutions with Single-stage Devices• Solutions with Multi-stage Devices• Some ‘exotic’ applications• Conclusions

Two recent, excellent reviews: F.Sauli, 8th Pisa Meeting on Advanced Detectors, Elba 2000

A. Sharma, IEEE NSS and Medical Imaging Conference, Lyon 2000



Electric field Signals



Spatial resolution = 30.5 ± 0.4 m

Overall spatial resolution

Ne(25)-DME(75)Vcath= -530 VVdrift= -3000 V

MSGC

Residuals distribution



Global Occupancy at different S/N (ORCA2 sim.)

48 minimum bias events in 3 bunch crossings

MSGC



1.1

1.0

0.9

0.8

0.7

0.6

Relative gain

6 7 8 90.1

2 3 4 5 6 7 8 91

2 3 4 5

Rate (MHz/mm2)

Vd= -3000V, V

c= -460V

Pestov glass coating

ρbulk=10 10 Ωcm

ρbulk=10 11 Ωcm

MSGC

- INFN Pisa

: 5.4 -Source KeV Cr X rays- (50/50)Ne DME

Vd= -1000 , V V

c= -564V

263 D uncoatedρ

surface=510 17 Ω/square

Rate capability > 1 MHz/mm2

MSGC



Efield on insulating substrate

Efield on thin conducting layer(coating) over insulating substrate

Uncoated MSGC

Coated MSGC

MSGC



At high gain on exposure to heavilyionizing particles possible discharges

MSGC

Advanced passivation

Standard passivation

A. Bressan et al., Nucl. Instr. Meth. A424 (1998) 321

Solution! Cathode edge passivation



Telescope of 32 MSGCs tested at PSI in Nov99 (Milestone)

MSGC



MSGC

350-400 MeV/c +/p beam.MIP spectrum with non-negligible HIP rate.

4 channels (out of 16000)lost in ~400 hrs run

32 days exposure @LHC rate! (Max rate ~6 KHz/mm2 )

R. Bellazzini et al., Nucl. Instr. Meth. A457 (2001) 22

Spark rate 1/day/detectorin the whole telescope



Measured spark probability 4 10-13

MSGC



MSGC

Strip loss historyduring the whole

PSI Test Beam period (5 weeks H.I.)



MSGC

Detection efficiency vs S/N

~ 98% at S/N = 13



MSGC

Example of gain stability at low and high intensity

3 weeks run

3 weeks run



Exploited2D-Reconstruction capability

with Pion beam

MSGC



Summary of PSI-Milestone for CMS Barrel MSGCs

• 32 barrel modules exposed for 5 weeks of HI at PSI;• no single access, no single short, no cathode trips;• lost 40% of 1 strip and 2 electronic channels (3 including margin phase);• margins explored up to a factor 2.4 without any significant increase of spark rate and strip loss;• lifetime = 20 times the expected one;• system brought back in perfect integrity ( < 1.4 % dead channels)• measured discharge probability = 4 10-13

MSGC

From the Addendum to the CMS tracker TDR by the CMS collaboration:“ In the fall of 1999, the large scale PSI Milestone (~40 k strips exposed for 5 weeks) resulted in an unambiguous demonstration of the viability of the CMS MSGC’s for tracking at the LHC.”



GEM

F. Sauli, Nucl. Instr. Meth. A386 (1997) 531

70 m

140 m

Transfer

MultiplicationConversion and drift



GEM + MSGC

Applications: HERA-B, CMS Forward Tracker



GEM + MSGC

HERA-B Detector



GEM + MSGC

M. Holhmann, 8th Pisa Meeting on Advanced Detectors, Elba 2000

HERA-B:High rate experiment



GEM + MSGC

HERA-B Inner Tracker: the world’s largest Micro Pattern Detector

MSGC-GEM detectors

Rmin ~ 6 cm

106 particles/cm2•sec300 m pitch184 chambers: max 25x25 cm2

~ 10 m2

140.000 channels

M. Holhmann, 8th Pisa Meeting on Advanced Detectors, Elba 2000



GEM + MSGC

HERA-B : Spark rate and exposure time

Gem+MSGC appear to be adequate solution even if they need long and careful HV training in the beam



GEM + MSGC

Courtesy F. Eisele (Desy)

HERA-B GEM+MSGC

Hit efficiency ~ 90÷96 % (after individual VGEM adjustment)



GEM + MSGC

HERA-B : tracks in the Inner Tracker

Courtesy F. Eisele (Desy)



CMS Forward Tracker

PSI Test Beam Set-up18 MSGC+GEM modules

GEM + MSGC



GEM + MSGC

High intensity event reconstruction

CMS Forward MSGC+GEM modules

M. Ageron et al., Preprint sub. Nucl. Instr. Meth., 21 June 2000



Detection efficiency vs S/N


PSI low intensity run

GEM + MSGC

~ 98% at S/N = 17




GEM + MSGC

(HI runs @ S/Npremux ~ 37)

Mile

ston

e ce

iling

Strip loss history during the 3 weeks

of PSI-Milestone Test Beam



GEM + MGD

PSI99 M1 TB - Low Intensity S/N

Two-stages Micro Pattern detector: GEM + MicroGroove Detector



GEM + MGD

1 week high intensity run: NO sparks, NO loss of strips or electronic channels at low transfer field (4 kV/cm)

PSI99- M1 Test beam



Double - Triple GEM

S. Bachmann, CERN-EP/2001-151

Double-GEM detector

Discharge probability vs gainfor -particles

Fast read-out (electrons) 2D capability Single GEM (uniform field) more prone

to sparking than MSGC (sharp field)



Double - Triple GEM

The PSI M1 beam @ 300 MeV/creproduces very well LHC spectra

-beam

-particles



Double - Triple GEM

PSI installation: large area (31 x 31 cm2) segmented GEMs

COMPASS Double GEM



... even though the detectors experienced several thousands of discharges in the course of the discussed test beam experiments, damages were not observed neither to the GEM foils nor to the readout electronics.(S. Bachmann et al., CERN-EP/2000-116)

Double - Triple GEM

COMPASSDouble GEM prototype



Double - Triple GEM

COMPASS

B. Ketzer IEEE NSS and MI Conference19 October 2000



Double - Triple GEM

Triple GEM detector forLHCb inner tracker

Detection efficiency vs GEM Voltage

M. Ziegler et al., hep-ex/0007007, 6 July 2000

375V



Double - Triple GEM

@ 375V (beginning of plateau)Discharge probability

≈ 8.3x10-12

(45 sparks in 2 det. in 12.5 hrs)

M. Ziegler et al., hep-ex/0007007, 6 July 2000

Gain and Discharge probability vs GEM Voltage



Applications: MSGC

The JEM-X Project on INTEGRAL ( a -ray observatory satellite)Danish Space Research Institute

To be launched this year by ESA



The JEM-X Detector consists of 2 identical, high pressure, 2D-MSGCs.

The gas filling is a mixture Xenon-Methane (Gain ~ 1500).The diameter is 250 mm, corresponding to a collecting area of 500cm2

Applications: MSGC

Qualification model2D-MSGC plate



Applications: MSGC

Spectral sensitivity of the JEM-X qualification model

Courtesy C. Budtz-Jorgensen (DSRI)



Applications: MSGC

Response of JEM-X to a full area illumination

Courtesy C. Budtz-Jorgensen (DSRI)



GEM + Pixel Read-Out

The complete separation between the amplification structure and the pick-up electrodes allows full flexibility on the choice of read-out pattern GEM+Micro Pixel electrode

Recent applications: X-ray PolarimeterTime resolved plasma diagnostic



GEM + Micro Pixel Read-Out

∂σ∂Ω

=ro2

5Z4137mc2

hν

⎛ ⎝ ⎜ ⎞

⎠

724 2

2sin θ( )2cosϕ( )

1−βcosθ( )( )4

Heitler W.,The Quantum Theory of Radiation

8-layer read-out boardPixel size 0.2 mm Area 2.4 x 2.4 mm2 (128 pixels)

X-ray Polarimeter




Reconstructed emission angles of the photoelectron

Photoelectron tracks reconstruction(larger boxes == larger energy losses)

Unpolarized photons

E. Costa et al.

Polarizedphotons

Interaction point and Auger e-




Observing time to measure at 99% confidence level the degree of polarization of galactic and extra-galactic sources with traditional and MP polarimeters

Degree of polarizationExtra-galactic sources



New implementation:512 independent chans out of 30 mm2 area




GEM + Macro Pixel Read-Out

Ultra-fast system for X ray imaging based on GEMNew diagnostic device in soft X range (315 KeV) for magnetic fusion plasmas

Printed circuit board128 pixels (2.5 x 2.5 cm2)

Parallel read-out




The inner toroid

The Frascati TOKAMAK (FTU)

Bt = 8 T, Ip = 1.6 MA R = 0.93 m a = 0.3 m




Linearity of GEM current at very high counting rates.Counting rate linear up to 2 MHz/pixel (limited by electronics dead-time)

D. Pacella et al., Review of Scientific Instrument, Vol.72 No.2 (2001)




1 KHz sampling - 3 MHz/pixel counting rate

Shot 18608

-500

0

500

1 000

1 500

2000

2500

3000

3500

0.00E +00 2.00E +02 4.00E +02 6.00E +02 8.00E +02 1 .00E +03 1 .20E +03

ti me (ms )

Multiple injections of D2 pellets

Time (ms)

Time response from 4 pixels for ohmic plasma

Co

un

ts /

ms




X-ray time response for two different injection runs

20 KHz sampling, 3 MHz/pixel counting rate

Normal

Aborted




Imaging capabilities at high rates (2MHz/pixel)

Image of a wrench placed close to the detector

Exposure time = 50 ms



Double GEM + Macro Pixel Read-Out

0

1000

2000

3000

4000

5000

6000

7000

8000

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106 113 120 127 134 141 148 155 162 169 176 183 190 197 204

V=1900

V=2050

B

O

B

O

183 eV

523 eV

Spectra of B (183 eV) and O (523 eV) in vacuum

Double GEM Gain = 20000

C. Buttner et al., Nucl. Instr. Meth., A409 (1998) 79

D. Pacella et al.




Thresh.> 0.1 KeVThresh.> 0.6 KeV

Spectral map and composition of fusion plasma

Courtesy of D. Stutman, Johns Hopkins University



New Micro-Pattern Structures

F. Bartol et al., J. Phys III France 6 (1996) 337

MICROCAT

A. Sarvestani et al., Nucl. Instr. And Meth. A410 (1998) 238

Compteur a Trou (CAT)



MICROMEGAS

Y. Giomataris et al., Nucl. Instr. And Meth. A376 (1996) 29


Large MICROMEGAS (40x40cm2) for COMPASS

Y. Giomataris, F.Kunne, F. Jeanneau, P. mangeot

Low field: conversion and drift

Very high field: multiplication




MICRO-WIRE chamber MICRO-PIN ARRAY Detector (MIPA)

B. Adeva et al., Nucl. Instr. And Meth. A435 (1999) 402

P. Rehak et al., IEEE Nucl. Sci. Symposium seattle 1999



Conclusions

• The field of Micro Pattern Gas Detector is STILL showing great vitality and propulsion.• Single stage and Multistage Devices showed suitable for tracking at high luminosity.• Competition of solid state devices is becoming HARD, especially at hadron machines.• Great potential as X-ray detectors.• Coupling of distributed amplification structures (GEM,…) to separate, pixel read-out structures seems the most exciting perspective.

Micro Pattern Gas Detectors VCI- Vienna Conference on Instrumentation 2001 R.Bellazzini - INFN Pisa1...

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