(1) At the 3PM operations meeting today it was decided that we will
run beam from now until 8AM Friday. At this point in time, it is
planned to have the hall open during Friday day shift unless
circumstances change and dictate otherwise.
(2) The plan is to bring the Cerenkovs into full operation. As of
this morning, there were no ADC events in left Cerenkovs 2 and 3
(counting from 0) and there were TDC events in 2 but not 3. This
needs to be investigated and fixed. It is known from the work in
the DTF that these two Cerenkovs were matched to a gain about a
factor of 2 lower than that for LC0 and LC1, which look pretty
good. Nevertheless, some signals should have been seen. So I
suspect that there are multiple problems, some with DAQ either
software or hardware and some with the gain of LC2 and 3. Also
in the right sector RC1 has low gain.
We cannot wait for an automatic gain matching software package.
We need to make the approximate adjustment immediately. Since
most PMT gains scale as HV to the 7th power (approximately), an
HV change of 10% on all 12PMTs in each of LC2, LC3, and RC1
should be made immediately. We can make fine adjustments from there.
There are still some problems with some TOF channels. Tancredi has
addressed some of these in his recent note to BlastTalk. In addition,
RTOF 15 top and bottom TDCs are empty, RTOF4 top ADC is missing.
It is not known whether these are signal problems from the detectors
or electronic mapping problems. This also applies to LTOF14 and 15
which are switched into the ADCs (could be a patch panel switch or
a missmapping). The LTOF13 bottom ADC is empty. All other TOF ADC
channels look OK. There are clearly some gain matching issues to
address but this is second order.
The plan, as Ricardo has mentioned, for the next several days is
to do final trigger and detector work during the days and evenings
and give the beam over to the Compton Polarimeter group in the
midnight to 8AM shifts. Upon completion of the trigger, the WC
group will take the days and evenings. Thus for the next several
days we will continue to need trigger, detector, and DAQ experts
on day and evening shifts. By the end of the week WC experts will
be sitting on shift as well to look at WC reponses with beam.
-- John R. Calarco Dept. of Physics Univ. of New Hampshire Durham, NH 03824 phone: (603)862-2088 FAX: (603)862-2998 email: calarco@unh.edu
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