Simulation for application of Geiger mode APD to Aerogle RICH counter

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Simulation for application of Geiger mode APD to
Aerogle RICH counter
2006/12/07 Yuri MAZUKA
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Motivation and contents

• Estimate the merits to apply Geiger mode APD to
  Aerogel RICH counter
• Geiger mode APD
• Not influenced by magnetic field
• High resolution to detect single photon
• The biggest problem ? the size (currently?1mm)
  our needs?5mm

Consider good design of light guide to extend
effective area
Simulate the performance of a) PMT , b)
Geiger mode APD with light guide
How increase the Npe compare with PMT?
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Light guide design

• Collection efficiency depends on the length of
  trapezoid light guide

?1mm
?2mm
?Size of Geiger mode APD?

• Incident angle 0.30rad (Cherenkov angle in the
  case of Pp4.0GeV, n1.05)
• photon l 413nm
• Acrylic(n1.49), no absorption

Adopt this design
_at_12mm CE37
_at_12mm CE95
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design of light guide determined
Simulate the performance of a) PMT , b)
Geiger mode APD with light guide
How increase the Npe compare with PMT?
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Comparison between Geiger mode APD and PMT
realistic data
PDE(photon detection efficiency)
Flat panel PMT(HPK H8500)
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Geometry
5.8mm
a) Flat panel PMT
0.16mm
z
beam
Single channel of PMT
y
Aerogel
x
200mm
b)Geiger mode APD with light guide
z
10mm
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a) Cherenkov ring on PMT
Simulating beam test conditions by Geant4
Photo detector40x40 array(243x243mm)
Beam500events4.0GeV/c p-
AerogelThickness 10mmRefractive index
1.046(l400nm)
Cherenkov ringq0.3radr62mm

• Blue(green dot) detected
• Black not detected
• White go out of effective area

Generated Cherenkov ring looks O.K.
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a) Simulating results with PMT
Events of each process
Position of detected photons
generated
reach to sensor
detected
Npe/event 8.70.1
(Few Rayleigh scattering events are included)
Each process looks working well
Npe is 2 times lager than real beam test data
How correct the physics process in Geant4?
But comparison of the ratio can be reasonable
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b) Cherenkov ring on Geiger mode APD
The same condition of the case of PMT
Photo detector40x40 array(200x200mm)
Beam500events4.0GeV/c p-
AerogelThickness 10mmRefractive index
1.046(l400nm)
Cherenkov ringq0.3radr62mm

• Blue(green dot) detected
• Black not detected
• Pink absorbed in guide
• Yellow scattering on guide surface
• White not reach to guide surface

Generated Cherenkov ring looks O.K.
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b) Simulating results with Geiger mode APD
Events of each process
Position of detected photons
generated
reach to guide
reach to sensor
detected
Npe/event 24.30.1
Each process looks working well
2.8 times larger than PMT(Absolute value of Npe
may not be realistic)
How about the angle resolution?Actual condition
dark noise is added
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Summary

• Light guide design is optimized
• Geiger mode APD has ?2mm?CE95
  (no loss due to light guide
  shape)
• Estimate the performance of Aerogel RICH with
  the light guide and Geiger mode APD
• Npe can be 2.8times larger than NpePMT

To do next To make the estimation of Npe more
correctly, check parametersMeasure photon
detection efficiency(PDE) of Geiger mode APD
sample by ourselves
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Simulating parameter 1

• Beam
• P4GeV/c, p-
• Incident angle 0rad
• 500event

• Optical photon
• 200nmltllt900nm
• Including physics process
• Rayleigh scattering process
• Cherenkov process
• Snells raw

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Simulating parameter 2

• Aerogel radiator
• Thickness 10.0mm
• Transmission length(l) 1.09228.06mm
• Refractive index(l) 1.0461.057

Transmittance()
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Simulating parameter 3

• Acrylic (material of light guide)
• Transmission length(l) 0.0100mm
• Refractive index(l) 1.4811.558
• Reflectance(l) 4

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Details of parameter
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b)Geiger mode APD with light guide
a) Flat panel PMT