14 july 2003 mark oreglia, lcw cornell 1 progress on rpc tests at the university of chicago outline:...
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14 July 2003 Mark Oreglia, LCW Cornell 1
Progress on RPC Tests at the University of Chicago
Outline:• Prototype chamber• Gas mixer• Pulses and spectra• Future plans
14 July 2003 Mark Oreglia, LCW Cornell 2
The Default Design
• ANL was kind enough to send us a chamber, which we have reworked several times
• Our aim is to test gas mixtures and look for surface damage, so we have a single readout pad
• The resistive layer is sprayed graphite
• Initial gas: R134a:Ar:Isobutane 62:30:8• future: HARP: R134a:Isobutane:SF6 90:5:5
• All tests use CR telescope and trigger
14 July 2003 Mark Oreglia, LCW Cornell 3
14 July 2003 Mark Oreglia, LCW Cornell 4
Gas Mixer
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Good Pulses
• It appears we have been seeing streamers, not avalanches (thresholds?)
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Lots of double-pulses
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… and much spontaneous pulsing
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Trying to understand spectrum
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A Better CR telescope
• Ed Blucher + Aren Jensen + Abby Kaboth• Scintillator + DC for fine positioning• Look for hotspots, etc
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Good Position Info Now
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What We are Investigating
• Origin of spontaneous discharges• Effects of surface quality• Surface damage• Gas mixtures and their relation to the
problems mentioned above
• Gas pressure and chamber ballooning– A real problem…– Stable operation disrupted for very
slight deformation of chamber