december 10, 2008 1 the parallel plate chamber cern presentation wout kremers detector r&d...

December 10, 2008

1

The Parallel Plate Chamber

CERN Presentation

Wout Kremers

Detector R&DNIKHEF

December 10, 2008 2

IntroductionElectron Emmission Foil

Parallel PlateChamber

SimulationConclusion

Preliminary Results

Introduction

• Electron Emmission Foil• Parallel Plate Chamber (PPC)• Preliminary Results• Simulation• Conclusion

December 10, 2008 3




Preliminary Results

Electron Emmission Foil

• Incident MIP hits foil• Thin foil (atm 68 micron)• MIP frees electrons in foil• Few electrons will be close to surface of

foil• These can be amplified

FoilFoil

MIP

electron

December 10, 2008 4




Preliminary Results

Parallel Plate Chamber

Copper coated Kapton Foil Cathode

Messing Block Anode

Mylar Foil Spacer

50 micron

68 micron

December 10, 2008 5




Preliminary Results


• Gas amplification potential causes electrostatic force

• Spacer to keep distance and define active area detector

• Foil cathode placed under tension to limit bending effect

• To stabilise gas flow and pressure a perspex clamp was mounted on the pcb

December 10, 2008 6




Preliminary Results


December 10, 2008 7




Preliminary Results

Preliminary Results

• The pcb was connected to a high voltage supply, a 10dB output amplifier and a scope

• The chamber was flushed with 97,5% Argon and 2,5% Iso-butane

• Chamber was tested with Fe 55 and Sr 90 sources

December 10, 2008 8




Preliminary Results

Preliminary Results

0,008 0,010 0,012 0,014 0,016 0,018 0,020 0,022 0,024 0,0260

20

40

60

80

100

120Vo

ltage

(V)

Count

Fe 55 Spectrum at -361,4 V Applied Voltage

December 10, 2008 9




Preliminary Results

Preliminary Results

0,000 0,005 0,010 0,015 0,020 0,025 0,0300

20

40

60

80

100

120

140

Volta

ge (V

)

C ount

-351,1 V -354,2 V -361,4 V -365,3 V

F e 55 S pectrum at multiple A pplied V oltages

December 10, 2008 10




Preliminary Results

Preliminary Results

0,008 0,010 0,012 0,014 0,016 0,018 0,020 0,022 0,024 0,0260

20

40

60

80

100

120

140Vo

ltage

(V)

Count

Sr 90 Spectrum at -362.4 V Applied Voltage





Preliminary Results

Preliminary Results

• Some signals were below noise level• No gain could be directly seen from

spectrum• Measurement made of signal current• Current on the order of pico ampere





Preliminary Results

Preliminary Results

350 355 360 365 370 375 380 385 390 39550

100

150

200

250

300

Curre

nt (p

A)

Applied Voltage (V)

Signal Current vs Applied Voltage





Preliminary Results

Simulation

• So far only for Fe 55• Assumption all electrons created in gas

gap• Simple statistical approximation of

interactions• Monte Carlo simulation





Preliminary Results

Simulation

0 1 2 3 4 5 6 7 8 9 10

x 104

0

50

100

150

200

250

300

350

400

Number of electrons collected at anode

Coun

ts

Simulation of 5.9 KeV X-Rays in PPC





Preliminary Results

Conclusion

• Working chamber with small avalanche only gap

• Chamber which can be used to test foils• Different types of foils, eg carbon

nanotube coated foil• Foil efficiency will be determined through

beam test





Preliminary Results

Conclusion

• Future possibilities:• Electron emission

foil and micro channel amplification

• Electron emission foil and multi grid amplification

electron emission foil

CMOS pixel chip

electron emission foil

CMOS pixel chip





Preliminary Results ?

december 10, 2008 1 the parallel plate chamber cern presentation wout kremers detector r&d...

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