Present at the Gran Sasso during at least part of this period, in no particular
order: Erik Katsavounidis, Ioannis Katsavounidis, Sophia Kyriazopoulou, Massimo
Orsini, Valeriano Marrelli, Nicola Zaccheo, Lynn Miller*, Stuart Mufson
* the very-late-with-her-report shiftworker
The overall status of the detector for the period of this report was quite
good, with few unanticipated interruptions in data-taking.
Week 1
------
At the scintillator group meeting on May 14, we gave Erik's new event-browser a
trial run, viewing an event that Valeriano had selected for its monopole-like
signal. The details available from the browser allowed us to determine that
this was a spurious event resulting from the death throes of the end-1 PMTs in
tank 4T11. Doing this diagnosis as a group exercise helped familiarize us with
the browser and gave Erik some feedback concerning refinements and additional
desirable information that might be programmed into it.
Calibrations done on May 12 included LED TDC and laser calibrations on
microVAX2, and FMT on microVAX3. Repair and maintenance operations during the
prior week included the replacement of the PMT bases in tank end 4B01-01, and
changeout of the driving op-amp (LM 6151H) on 2CL-0. The problem on 2CL-0 had
caused the HIPT trigger to be dead, as well as the corresponding output of the
CSPAM system fan-in/fanout, for runs 17532 through 17592.
The shiftworker-reporter had spent her work time on a project to transfer the
production of .TRK and .CAL files from VXMACB to the AXP machines in the
external lab. This first week's effort consisted chiefly of becoming familiar
with the programs that produce these files used for calibrations. The .TRK
files result from the submission of the MAKETRK program at the end of a
BMONITOR run, while .CAL files are produced in the USER3 subroutine of
BMONITOR. Moving MAKETRK to the AXPs would seem to be relatively
straightforward, but separating the production of .CAL files out of the several
functions performed in the USER3 routine not necessarily so easy. See the next
week's report for continued developments.
Week 2
------
Several problems were diagnosed and fixed on Wednesday, May 19. These
included:
(1) the replacement of both PMTs in 4T11-01. This counter had been unplugged
from the TOHM trigger for a couple of weeks because of excessively high rate.
The replacement of the PMTs resulted in a much reduced TOHM rate, but Massimo
suggests that monitoring it should continue because of helium contamination in
the tank end and because the testing of the spare PMTs used as replacements was
less thorough than he would have liked.
(2) the replacement of the ERP trigger processor for channels 1C13, 1C14, 1C15,
and 1C16. Before the fix, the affected ERP muon and GC channels were dead
during runs 17625 through 17628.
(3) a fix for the high rate of No-Q-Responses coming from the SM2 WFD
Stopmaster. The runs with the worst incidence of No-Qs included runs 17625
through 17628, but the problem had been in some evidence since run 17601. The
problem was found to be due to a poor connection of the S1 (SM1 WFD Stopmaster
signal) cable to the SM2 WFD Stopmaster. Once this cable was properly plugged
in, the No-Qs disappeared in a mini-acquisition run. Ioannis suggested keeping
an eye on this and replacing the corresponding cable connector if the problem
reappears. Run 17630 was the first good run after this fix.
(4) reconnection into acquistion of 14 TOHM channels that had been disabled
because of excessive TOHM rates. Because of their high rates, there was a dead
time increase and a shortening of the average run duration to about 4.8 hrs.
The disconnection had been done to verify that these channels were responsible
for the noted deadtime and run duration problems. Two of the channels had been
fixed by replacing bad tubes (4T11 and 4B01) as of May 19, and a detailed plan
for changing the remaining helium-contaminated tubes was scheduled to go into
effect the following week.
On the calibration software front, the MAKETRK program was successfully
compiled on the AXP platform and tested with several recent runs. The newest
version of DREAM (1.32) was used, but older versions of the database files for
calibrations and geometry, the same as those used on VXMACB, were employed for
the tests. Some differences were found in the .TRK files produced on the AXPs
as compared to those from VXMACB, but those differences could all be attributed
to an improvement in the tracking code for events crossing either the north
face or south face of the detector. Putting together the code to produce .CAL
files on an external lab AXP was not so successful. The attempt was made to
put this function into the MAKETRK program, with MAKETRK checking the online
logbook to determine whether the run was a calibration run or normal data run,
and then calling the appropriate subroutines to produce either .TRK or .CAL
files. The checking-of-the-logbook part was a success, but the code for
producing the .CAL files from calibration runs remained incomplete at my
(Lynn's) departure. Problems with pointers into the raw data banks brought the
effort to a standstill. If someone wishes to carry this work forward, I'll be
glad to tell you how to find the code I was working on. During the brief time
that Stuart's and Lynn's shifts overlapped, work was begun to test the
possibility of producing .TRK files from muon astronomy DSTs. Stuart planned
to continue with that effort after Lynn's departure, and the results of his
work will be reported in his (also overdue) shift report.
I hope the delay in the production of this report has not caused problems or
inconvenience for anyone. I also apologize for the lack of humor, but trust
that it will be compensated for when Dr. Mufson writes his report.
Respectfully submitted,
Lynn Miller