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F. Sauli, T. Meinschad, L. Musa, L. Ropelewski CERN, GENEVA, SWITZERLAND PowerPoint Presentation
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F. Sauli, T. Meinschad, L. Musa, L. Ropelewski CERN, GENEVA, SWITZERLAND - PowerPoint PPT Presentation


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PHOTON DETECTION AND LOCALIZATION WITH THE GAS ELECTRON MULTIPLIER (GEM). F. Sauli, T. Meinschad, L. Musa, L. Ropelewski CERN, GENEVA, SWITZERLAND. REFLECTIVE PHOTOCATHODE ON UPPER GEM SIDE: no photon feedback. MULTIGEM DETECTORS: VERY HIGH GAINS

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slide1

PHOTON DETECTION AND LOCALIZATION WITH THE

GAS ELECTRON MULTIPLIER (GEM)

F. Sauli, T. Meinschad, L. Musa, L. Ropelewski

CERN, GENEVA, SWITZERLAND

slide2

REFLECTIVE PHOTOCATHODE ON UPPER GEM SIDE:

no photon feedback

MULTIGEM DETECTORS: VERY HIGH GAINS

Single photoelectron detection with internal photocathode

R. Bouclier et al, IEEE Trans. Nucl. Sci. NS44(1997)646

S. Bachmann et al,

Nucl. Instr. Methods A 443(1999)464

D. Mörmann et al, Nucl. Instr. Methods 478(2002)364

slide3

EFFICIENCY AND RESOLUTION FOR UV PHOTON DETECTION

Multi-GEM with Cesium Iodide coating on upper side of first GEM:

Hydrogen UV lamp

R

HV

C

r

ADCs

T0

Collimator-attenuator

Quartz window

(inverted) drift field grid

GEM1 CsI-coated

GEM2

GEM3

Anode strip readout

slide4

SINGLE PHOTON DETECTION

Pulse height spectra at decreasing UV source intensity:

Single photoelectron spectra:

Multiple photoelectron spectra:

BEAM ATTENUATION

slide5

200 µm

160 µm FWHM

Beam ~ 100 µm FWHM

Intrinsic accuracy

~ 50 µm rms

SINGLE PHOTOELECTRON POSITION ACCURACY:

Two positions of collimated beam 200 µm apart

T. Meinschad, L. Ropelewski and F. Sauli, Vienna Conference (Nucl. Instr. and Methods, in press)

slide6

GEM RICH: MULTIPLE PHOTONS

Hexaboard closeup: 520 µm Ø pads

Hexaboard readout: matrix of hexagonal pads interconnected along three projections at 120º

U

V

W

S. Bachmann et al

Nucl. Instr. and Meth. A 478 (2002) 104

slide7

16 strips

16 strips

16 strips

8.3 mm

HEXABOARD DETECTOR

Standard assembly for 10x10 cm2 GEMs, 3x128 strips

3x16 strips readout: fast charge amplifier+ALTRO (FADC, 10 bit-25 MHz sampling)

ALTRO:

B. Mota et al,

Nucl. Instr. and Methods,

in press (2004)

slide8

SINGLE PHOTON EVENT:

16 strips

8.3 mm

slide9

SINGLE PHOTON CLUSTER WIDTH (rms)

  • ~ 0.5 pads (250 µm)

Charge sharing (520 µm pad rows)

slide10

2.4 mm

1.1 mm

1.3 mm

DOUBLE PHOTON EVENT:

slide11

CHARGE CORRELATION BETWEEN THE PROJECTIONS:

SINGLE PHOTON CLUSTERS

U-V

W-U

V-W

slide12

Scintillation

DETECTION OF INTERNAL SCINTILLATION IN XENON

CsI - Quad-GEM in pure Xenon

X-ray

Ionization

G. Charpak, S. Majewski and F. Sauli, Nucl. Instr. and Meth. 126(1975)381

L. Periale, V. Peskov, P. Carlson, T. Francke, V. Pavlopulos, P. Picchi, F. Pietropaolo,

Nucl. Instr. and Meth. 478(2002)377

(See also V. Peskov N25-3)

slide13

Primary scintillation

PRIMARY SCINTILLATION IN XENON-CsI

22 keV from 109Cd

slide14

TIME DIFFERENCE PROMPT- MAIN PULSE

LOW DRIFT FIELD: PRIMARY SCINTILLATION

Efficiency

2% for 5.9 keV

10% for 22 keV

slide15

Secondary scintillation

HIGH DRIFT FIELD: SECONDARY SCINTILLATION

slide16

TIME DIFFERENCE PROMPT- MAIN PULSE

HIGH FIELD: SECONDARY SCINTILLATION

5.9 keV X-rays

Efficiency for 5.9 keV

20% at 1.3 kV/cm

66% at 1.9 kV/cm

76% at 2.5 kV/cm

slide17

CONCLUSIONS

MULTI-GEM DETECTORS WITH CsI PHOTOCATHODE:

HIGH GAIN-EFFICIENT UV PHOTON DETECTION

VERY GOOD POSITION ACCURACY ~ 50 µm rms

WITH HEXABOARD READOUT:

GOOD MULTI-HIT RESOLUTION ~ 2 mm

GEM-CsI FOR DETECTION OF SCINTILLATION IN Xe

EFFICIENCY FOR PRIMARY SCINTILLATION ~ 10% FOR 22 keV

EFFICIENCY FOR SECONDARY SCINTILLATION ~ 80% FOR 5.9 keV

TOWARDS A PARALLAX-FREE X-RAY DETECTOR?

slide18

SECONDARY SCINTILLATION IN XENON

C.A.N. Conde et al, IEEE Trans. Nucl. Sci. NS-24 (1977) 221

slide19

Large size Hexaboard for MICE (Muon Ionization Cooling Experiment):

Manufactured by CERN-EST workshops

31 cm

V. Ableev et al, Nucl. Instr. and Meth. A518(2004)113

slide20

Gas Electron Multiplier (GEM)

70 µm

140 µm

F. Sauli,

Nucl. Instrum. Methods A386(1997)531