[BLAST_SHIFTS] Status of the wire chambers (2)

From: Michael Kohl (kohlm@mit.edu)
Date: Sat Oct 23 2004 - 09:25:32 EDT

Running for nine hours over night with the left branch valve open only
25%, still did not change either set of drift time spectra left or right.

Instead of going another factor 2, we will do the following test:
When we detached the left-sector system and flowed gas only through the
right sector two days ago, we had noticed an immediate improvement of the
right sector spectra, then being operational after a few hours.
We will repeat this procedure of detaching the left sector now by closing
the valve completely.
Also, the low voltages and the high voltages of the left sector will then
be turned off for the duration of this test.
Since a factor 4 if impedance increase in the left sector did not lead to
changes, it seems also possible (or likely) that the right sector may have
developed a leak or the contamination has become worse for other reasons.
Repeating this test of using the right-sector branch only will let us
conclude. We'll run like this until some time in the afternoon.

1) If the right-sector spectra recover, then there should still be an
optimum valve position benefitial for both sectors, to be adjusted in the
afternoon.

2) If the right sector doesn't recover, then we have a more serious
problem to be addressed next week. We then would open the valve again to
flow the left chamber again and take data for GEn.

Regards,

  Michael 

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