Reported by: Hwi Kim
Present: Hwi Kim, Massimo Orsini, Nicola Zaccheo, Roberto Giuliani
So, what is it like to be at Gran sasso over the Christmass-New Year
holiday? With only a handful of people around, LNGS has the feel of a
monastery. One can do some hiking along trail that begins at the ski lift,
although one has to stop in the midway to the top because the trail becomes
dangerously slipery due to the seasonal snow. I don't remember the last time
I had such a pleasant excercises. Also, one cannot help but to reflect
on the deep truth in the cosmic scale because the stars shine so brilliantly
over the night sky by the time one comes out of the tunnel. Try to imagine
this: Being up in the mountain away from most of the civilization, where the
stars twingkle ever so brightly in the night, and the only daily subsistence
is Italian cuisine, wondering how the Universe(s) came to be and what will
become of it(them).
The shift report
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There were some of the usual minor problems with PHRASE power supply,
PHRASE synchronization. And then, there were some unusual minor problems
(minor only because it didn't happen over night) of the DAQ misteriously
quitting. Probably the most significant problem occured on the run 16929 on
the 5th of January 1999, when the phototube on 4T08-1 started to flash and the
box had to be turned off.
Tank end operations
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As the result of gain resetting undertaken during the previous shift,
some tank ends that needed intervention were identified. During this shift,
nine of those operations were still going on: 4B11-1, 4B12-1, 4C01-1, 4C06-1,
4T08-1, 4T12-1, 5T10-1, 6B11-0 and 6C04-1. Of those nine tanks that were
operated on, 4T10, 6B11 and 6C04 showed high ERP GC trigger rate, and new
LUT is loaded for them.
Remaining work on LUT
---------------------
The box 6B11 needs a high energy threshhold to lower the ERP MU
trigger rate. The high ERP GC trigger rate from 1N02, 6S02 and 6S03
need to be lowered. The MACRO data on these boxes were not consistent with
the parameters in CALMOD and LUT. This inconsistency needs to be understood
and new LUT should be produced for those boxes. The gains on opposite ends
of another box, 6E06, are very assymetric and gain change on either side is
neccessary before effective threshhold can be applied.
WFD overflow
------------
There were WFD overflows (or nearly so) from some channels all in
the SM 2, that are not fixed yet. Those channels in the last few days are:
0, 1, 2, 4, 12, 24 and 32.
2. Calibration and maintenance
------------------------------
On Dec. 30 1998, LED calibrations were successfully done on mVax 2
and 3. Slow monopole calibration with the lowest beta is done on the whole
detector. However, two laser failed: mVax 3 lower and mVax 1 attico.
On Jan. 6 1999, we decided to take data instead of doing the the faled slow
monopole calibrations.