Transcript 2007/12/20 reports

12.20 report
LIU Qian
We found a noise on the -6V of pre-amp. We don’t know where it
comes from.
DC1M 2.00 V/div
50 ms/div
So we used another low voltage, and measured pkpk after pre-amp. 10,000 events.
Fit with the histogram with Gaussian, we got: 1.279 ± 0.030 V.
reflection
20 ns/div
Then read Ref PMT from USTC module
0.03 pC/channel
690.7 ± 13.3 (1.9%)
718.9 ± 17.3 (2.4%)
After that, we used the USTC module to measure the laser signal.
The IHEP DAQ program still doesn’t finish. So we have to use
the USTC program to acquire the data. (but USTC program has some bugs,
and can only read 88 TOF data).
We set all HV as 1050V, closed the west shuttle. Then we analysis the T(sub)
= T(tof) – T(ref), and fit with Gaussian.
Technically, only the west TOF end can have the signal because we only
pulsed the east side laser, the east TOF end can only have some reflection
laser. But we found that some east TOF does have signal, and west TOF
doesn’t have signal. We’re still looking for the reason. Maybe the HV is not
enough.
The mean and sigma of west end TOF T(sub)
We’re looking for the reason.
Conclusion
• At least, everything is working now.
• I do really want to check all fibers are OK first, but I think
the DAQ won’t be ready. Maybe I should check them one
by one by the oscilloscope.
• We installed west 17 bundles to the distribution boxes
today. There are only 7 bundles left now.
LIU Qian