Questions & Comments


Discussion led by Andreas Schwarz

	Questions & Comments

H. Kolanoski: I'm wondering if Ar/CO₂ is really unsafe? Or were the test conditions bad in the setup where fast aging was observed?

J. Vavra: 1) I do not understand that people dare to use RTV, not clean solder flux, use double-sided scotch tape, push the gas gain to >10⁵ and somehow hope to cope with LHC rates. Sounds like pushing luck. It is also a "bad" message to management.

2) Already in the 1986 LBL workshop it was realized that CF₄ may have very unstable chemistry. Yasuda said the same thing. I wonder if it is wise to push CF₄ gas components in ALICE or HERA-B. Water is blamed, but perhaps it is CF₄. I think the experiments should be ready to drop CF₄.

3) A look at the etching vs deposition rate suggests that the high-current aging tests may provide too optimistic results.

4) Perhaps, experiments should have a)heated stainless steel tubing, and b)dummy aging chambers all running to verify the gas system before the final chamber is connected. This should be done a long time before the beginning of the experiment.