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About LHC RPC systems |
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ATLAS RPC - Barrel:
- Counting rate a L=1034
cm-2s-1: 10-20 Hz/cm2
- Average expected rate (safety factor ~5): 100 Hz/cm2
- Accumulated charge in 10 years of operation: 0.3 C/cm2
CMS RPC - Barrel:
- Maximum rate: 50 Hz/cm2
- Accumulated charge in 10 years of operation: 0.05 C/cm2
ALICE RPC:
- Counting rate a L=1034
cm-2s-1:
- Average expected rate (safety factor ~):
- Accumulated charge in 10 years of operation:
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Gas mixture & gas system R&D
(Data from the studies being carried out at the
CERN Gamma Irradiation Facility (July 08 - now) |
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Set-up |
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GC/MS Analysis of the RPC gas mixture (Supply
Gas VS Return Gas of irradiated RPCs at the GIF ) |
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Study of Absorbers (R.Guida,
I.Glushkov) |
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Conditioning of Absorbers:
Main components of the RPC gas mixture can be trapped in
some absorbers during their first operation (measured to be
up to 10-100 gas volume exchanges). This effect
can alter
temporarily the gas mixture composition. This is very
relevant for the operation of closed-loop gas systems, where
the purified gas is sent back to the loop. In order to solve
the problem a so-called conditioning phase has been
introduced that consists of flushing the absorbers with
process gas till the output mixture is back to normal.
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| MS 3A |
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| MS 4A |
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| MS 5A |
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| Cu (BASF R11) |
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| Cu/Zn (BASF
R12) |
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| Ni Al2O3 (Leuna) |
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| Ni SiO2 (Leuna) |
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Performance of the RPC Chambers
irradiated at the GIF (R.Guida) |
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| Accumulated C/cm2 VS time
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Bakelite Resistivity VS time |
Ignition Voltage
measured in 100% Argon |
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