Test of RPC at 5T Magnetic Field

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Test of RPC at 5T Magnetic Field

• V.Gapienko, A.Semak
• IHEP, Protvino
• presented by
• F.Sefkow
• DESY

The main goal of the test was to check to which
extent strong magnetic fields affect RPC
operation in avalanche mode. The test was done
at DESY in June 2004.
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Details of the test

• Three glass RPCs with 1.2mm gas gap each were
  used in the test two of them as trigger
  detectors and the third one as tested RPC.
• The RPCs were filled with TFE/isobut./SF6
  (93/5/2) and operated in avalanche mode.
• The tested RPC had 8x8 pads with 1x1cm2 size
  each. It was equipped with 8 8-channnel
  amplifier-discriminators OKA-1. The amplifier
  outputs were connected to the programmable
  logical unit Altera Acex EP1K50.
• A coincidence of signals from the trigger
  chambers triggered the Acex to store an event in
  its memory.
• The measurements were carried out with cosmics
  for 3 configurations
  a) magnet off
  
  b) magnet on, angle between magnetic
  and electric fields was 900 c) magnet
  on, the angle between fields was approx. 450.

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Scheme of the Setup
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An example of population in different pads after
1000 triggers
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An example of distribution on number of fired
pads in an event.
Obtained at HV7.3 kV
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Efficiency as a function of HV.
Each point is based on 300 triggers
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Mean multiplicity versus HV
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Summary

• Within statistical errors no differences in the
  RPC behavior were observed between the cases
  where the 5T magnet was on and where it was off.
• During the test all three chambers showed very
  stable operation.

Many thanks to people from the FLC group who
helped to get these results. Special thanks to
Valeri Saveliev.