Questions & Answers


Talk by Morris Binkley

	Questions & Answers

Q (V. Pantuyev): About the aerosols from alcohol: What purity of alcohol was used and what type of bubbler and diffuser was used?

A (M. B.): The alcohol used was 200 proof and of "laboratory" purity. The bubbler was constructed of stainless steel and the diffuser was a stainless steel mesh.

Q (F. Sauli): Some (most) of your problems seem correlated with a solvent effect of the alcohol (transporting dirt from pipes, valves, ... to chambers). Did you try to run without alcohol at all?

A (M. B.): We did not try to run the CTC without alcohol. Our tests had shown that alcohol reduces aging, improves chamber stability, and affects the Lorentz angle. I did present several results from monitor chambers for a variety of gases without alcohol.

Q (K. Lau): Do you look at the pulse height spectrum in your monitor chamber?

A (M. B.): We looked at both pulse height and current draw for the CTC (Run 1) results that we presented. Based on their agreement, we are planning to monitor only currents for the COT (Run 2).

Q (B. Schmidt): Why do you think the contaminant is of "aerosol" type? Why not some gaseous stuff reacting with the copper, especially if this is heated up?

A (M. B.): The initial season we suspected aerosols was that the aging rate decreased with distance from the alcohol bubbler. Also when we reduced the flow rate through the bubbler (raising the temperature to keep the alcohol content constant) and added Cu wool filters, the aging rate became very small. The Cu woll had special preparation and was heated to only ~50 deg C in this case, so we doubt that much reacted with it. Also the test chamber just downstream from the bubbler had deposits that were mostly elemental carbon, probably not the signature of a contaminant that would react with the Cu wool.