tavi gain matched some of the cerenkovs. now lcc0, lcc1, rcc0 and rcc1
are gain matched; he's working on the rest tomorrow.
after this, we re-positioned the slits (the newest positions are l = -4, r
= 12, t = 1, and b = -5). at an 85mA beam current and no gas in the
target, these slit values correspond to a trigger rate of 500Hz (using the
any_coincs trigger).
then we started taking runs dealing with cerenkov efficiency. the left
and right cerenkovs had both been using a threshold of 25mV. this
threshold is low enough to trigger on noise. after talking with
tancredi, we started the first runs in a series of runs that will
increment the cc's thresholds. using the any_coincs trigger, we took
approximately 1.5 hours of data with the cc's left and right thresholds
at 25mV. this data corresponds to runs 2453-457; there is roughly 1.5
million events in these runs.
the next step is to change the left and right cc thresholds to 35mV and
take data (still using the any_coincs trigger) for another 1.5 hours.
then change the cc's thresholds to 45mV, then 65mV, and then 85mV. take
1.5 hours of data for each cc threshold value. oh yeah, to change the
cc's threshold, go to the trigger gui and click on DEdgedisc and
REdgedisc.
we tried to use the cc_eff.C file to look at the cc's efficiency, but we
don't think that the file is finished.
aaron and nikolas
This archive was generated by hypermail 2.1.2 : Mon Feb 24 2014 - 14:07:28 EST