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. Mark Oreglia, LCW Cornell
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. Mark Oreglia, LCW Cornell
14 July 2003
Mark Oreglia, LCW Cornell

4. Mark Oreglia, LCW Cornell
Gas Mixer
14 July 2003
Mark Oreglia, LCW Cornell

5. Mark Oreglia, LCW Cornell
Good Pulses
It appears we have been seeing streamers, not avalanches (thresholds?)
14 July 2003
Mark Oreglia, LCW Cornell

6. Mark Oreglia, LCW Cornell
Lots of double-pulses
14 July 2003
Mark Oreglia, LCW Cornell

7. … and much spontaneous pulsing
14 July 2003
Mark Oreglia, LCW Cornell

8. Trying to understand spectrum
14 July 2003
Mark Oreglia, LCW Cornell

9. Mark Oreglia, LCW Cornell
A Better CR telescope
Ed Blucher + Aren Jensen + Abby Kaboth
Scintillator + DC for fine positioning
Look for hotspots, etc
14 July 2003
Mark Oreglia, LCW Cornell

10. Mark Oreglia, LCW Cornell
Good Position Info Now
14 July 2003
Mark Oreglia, LCW Cornell

11. 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
14 July 2003
Mark Oreglia, LCW Cornell