Currently at Gran Sasso : Maurizio Goretti, Hunmoo Jeon(shift worker),
----------------------- Erik Katsavounides, Sophia Kyriazapoulou,
Douglas Michael, Paolo Saggese, Stefano Stalio.
The slow monopole calibration was continued by Sophia, Hunmoo, Erik and
Doug on this Tuesday, Wednesday and Thursday. Normal data acquisition had
been stopped half day on Tuesday and Thursday and full day on Wednesday.
All the data was taken by Thursday night. The monopole calibration
program runs substantialy faster now. It takes aproximately 1 hr for
each supermodule if everything else is ready. In addition, WFD_ADC
calibrations on all uVAXes was done again with differnt pulse parameters.
The LEDs in veritcal tanks now produce long small amplitude pulse
necessary for slow monopole calibration. The problem was that LEDs in
the verticals are not terminated (thus reflect pulser signal). This problem
was noticed before and solved by adding resistors (50 ohm in series) on
the vertical channels. Somehow this work has been undone. The resisitors
were put back into the switch box by Maurizio, Paolo and Stefano.
During the slow monopole calibration a few dead (4-5) LEDs were found on each
supermodule (only the vertical tanks has been checked). The dead LEDs were
substituted with the 2nd LEDs in the tank. Replacement of the dead LEDs
are being planned by Doug in near future. Also some Switch boxes were found
to have dead channel(s). These Switch boxes were either fixed or swapped
with working switch boxes from other supermodules to continue the calibration.
Maurizio analyzed LED_TDC calibration data taken on last Wednesday. He
reported a strange scattering of TDC data as plotted against PULSE RATE.
The plot showed the data divided into two groups, separated by 20
nsec. Roughly 1/4 of the data fell in one group and the remainder in the
other. This was shown in both uVAX1 and uVAX2 but not in uVAX3. This
could be related to the jitter problem of LASER calibration reported earlier.
Further investigation will be performed on coming Wednesday. Three WFD
channels have been found to have rather higher pedestal (~20 mV). We
suspect this is the problem of noisy capacitor which have been removed from
most of the boards.
Stopmaster problem was investigated by Doug and Erik. It seems that the
stopmaster lose one or two bits tiem to time. However they concluded that
this problem will not seriously affect the normal data acquisition. More
detailed invetigation will be continued.
Paolo is building a test bench for TOHM cards. Roughly 90% of mainboard
has been finished. The main work that is left is building a case and panel
for the board. He also found a couple faulty CSPAM cable connectors on
SM6. These have been replaced with spare.
Stefano finished testing the unlabeled PMTs. He is working on VME bus test
bench for WFD board.
- Hunmoo Jeon -