Over the next few days we are trying to "condition" the wire chamber to
high voltage. This means gradually raising the high voltage on all wires
and watching the currents until we get to operating voltages. At present
almost all wires are at 2000 V and the currents for sense wires are ~0.4
microA, filed wires ~40 microA, and guard wires ~2 microA which are fine.
There are two cells in the left sector which at the moment can only take
1000 V and will have to be investigated during the next access to the South
Hall.
Meanwhile the HV to the wire chambers should remain on at all times
including during injection, etc. Specifically the HV crates for the wire
chambers should not be switched on and off like is customary with the PMT
HV crates. Tim's new HV daemon should do this.
Cheers,
Douglas
26-415 M.I.T. Tel: +1 617 258 7199
77 Massachusetts Avenue Fax: +1 617 258 5440
Cambridge, MA 02139 E-mail: hasell@mit.edu
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