Status Report for KEKPS E391a

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Status Report for KEK-PS E391a

• KEK IPNS
• G.Y.Lim
• 14 April 2003

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E391a experiment

• Collaboration
• High Energy Accelerator Research Organization,
  KEK
• Faculty of Science and Engineering, Saga
  University
• Department of Physics, Yamagata University
• Department of Physics, Osaka University
• Research Center for Nuclear Physics, Osaka
  University
• National Defense Academy of Japan
• Joint Institute for Nuclear Research (Dubna)
  Russia
• Department of Physics, University of Chicago,
  USA
• Fermi National Accelerator Laboratory, USA
• Department of Physics, Pusan National University,
  KOREA

• Measurement of BR( KL?p0nn )

• Two-step program
• (KEK-PS?JPARC)
• From the E391a
• Establish measurement principle
• Search for near SM expectation

• Data taking from Feb. 2004
• Engineering run
• Preparation of detector components

New KEK member Department of Physics, Kyoto
University
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E391a Detector
Engineering Run on last winter
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Engineering Run

• Fabricate on last summer

• DAQ using self-trigger of CsI
• Same scheme of real run
• Tuning / feed-back

• CsI calibration
• Cosmic test in vacuum chamber
• Cosmic test during stacking
• Punch-through muon
• Two gammas from single p0
• Multi-gamma decay (Kpi2, Kpi3)

• KL decay data same format of real run
• Develop on-line/off-line software

Significant step to the successful experiment
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DAQ with low noise level

• Distributed and parallel processing
• LeCroy 1885N FASTBUS ADC
• TKO HR-TDC
• Operation with tiny noise
• 1mV threshold for TDC ( 1 MeV)
• 50 fC ADC pedestal (0.1 MeV)

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Calibration using cosmic/punch-through muon
Good agreement between two gain factors !
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Calibration using p0-production
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Study using Kpi3 decay
Background free without veto system Comparison
with M.C.
- Good agreement
Calibration method in real run How to get correct
energy scale
Detailed study is going on
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Response at the high Intensity

• PMT gain (Xe monitoring system)

Same performance under the high beam intensity
7.0 X 1011 / 2s 1.4 X 1012 /2s 1.0 X 1012 / 0.2s
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Detector fabrication Upstream
Modules/vacuum chamber done
Assembling on June -July
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Detector fabrication Middle
Fabrication of 3 modules ? Finished 1 module/1
week ? End of Oct. (32 modules)
Design of assembling jigs final stage
Assembling Nov. Dec.
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Schedule
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Summary

• E391a is aiming for measuring the BR( KL?p0nn )
• Realizing Step-by-step
• Engineering run
• Stable data taking using same triggering scheme
  of real run
• CsI calibration cosmic ray data is very nice
  input
• No problem at high beam intensity
• Good agreement with M.C.
• Detailed study is going on
• E391a is preparing almost on schedule
• Downstream section is polishing stage
• Upstream/middle section being fabricated
  smoothly
• Prompt start at the real run (Feb. June, 2004)

- Full beam acceptable