Status of Japan Group and Beam Catcher

1
Status of Japan Groupand Beam Catcher
N. Sasao / T.Nomura (Kyoto U)

• Contents
• Status of Japan Group
• Progress in Beam Catcher
• Plan in 2002

2
Status of Japan Group

• Member
• Kyoto Univ. (N.Sasao, T.Nomura, 2 Grad.students)
• KEK (M.Kobayashi, T.Taniguchi)
• Kyoto U. of Education (R.Takashima)
• Funding Status
• Japan-US Cooperation
• 40k (JFY01), 80k (JFY02)
• Grant in Aid for Scientific Research
• 100k (JFY02), 700k in total (JFY2002-5)

3
Progress in Beam CatcherCatcher Baseline

• Lead-Aerogel Counter
• 20cm x 20cm x 5cm Aerogel (n1.03)
• 2mmt Lead converter
• 5-inch PMT
• Parabolic mirror
• Light collecting funnel
• Distributed Geometry
• 20/21 modules x 25 (20) layers
• 35cm apart in beam direction
• Coincidence along beam direction

4
Progress in Beam CatcherConcept of Mini Prototype

• Lead-Aerogel Counter
• 11cm x 11cm x 5cm Aerogel (n1.03)
• 2mm/20mmt Lead converter
• 5-inch PMT
• Plane mirror
• No light funnel
• Distributed Geometry
• 2 Layers (13 modules)
• 25/35cm apart in beam direction
• Coincidence along beam direction

5
Progress in Beam Catcher Mini Prototype Beam
Test at KEK

• Test at KEK 12GeV PS
• Charged Beam (p/p)
• Up to 2 GeV/c (Ekin,proton1.27GeV)
• PID by TOF and additional Aerogel

6
Progress in Beam Catcher Item 1. Light Yield

• Evaluate with p beam
• Results are
• 70 of expected yield (Npe6 _at_ 1GeV/c)
• Unexpected saturation effect
• Need more study
• Aerogels property
• PMT QE, effective cathode size
• Alignment?

7
Progress in Beam Catcher Item 2. Response to
Proton

• Proton beam as a substitution for Neutron
• Main difference between them is they can/cannot
  produce knock-on electron.
• If nuclear reactions being enhanced, their
  behavior expect to be similar.
• To enhance reaction events,
• Increase converters thickness of first
  layer. (2mmt ? 20mmt)
• Requirement of coincidence between layers
  automatically enhances reactions.

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Progress in Beam Catcher Item 2. Response to
Proton

• What we expected (GEANT simulation)

p
n
single
coincidence
9
Progress in Beam Catcher Item 2. Response to
Proton

• Results
• Rather high single hit rate
• Mostly 1 p.e. level
• Exist even if
• No Aerogel tiles
• Mask PMT window
• Any radiator remains?
• Secondary hits PMT?
• High coincidence probability
• Accidental?
• Real effect?

10
Progress in Beam Catcher Mini Prototype Summary

• Construct Mini Prototype and Test at KEK-PS.
• Measure light yield
• 70 of expected
• Measure response to proton
• Both single and coincidence probabilities are
  higher than expected.
• Secondary hits PMT directly?
• Random background?
• OR, this is correct?
• Detailed analysis in progress

11
Plan in 2002

• Light yield study
• Aerogels optical properties
• Refractive index
• Transmittance
• Measurement with electron
• Electron Synchrotron at Kyoto Uji campus
  (March-April)
• Tabletop calibrator with Ru source and solenoid
  lens
• Response to proton
• Re-test at KEK in May(?)
• Prototype with final dimension
• Large Aerogel fabrication
• Optics