Shift: 00:00-8:00 AM 07/27/02
Shift workers: TZ, DD
Summary:
Began persuit of the false asymmetry observed in the last 2/3 shifts.
The pockell cell HV was turned back on. The false asymmetry did not
reappear. We suspected the HV was not switching states. At first we could
not measure the voltage monitor or the gate. On retracing the signals
between the hut and D-tunnel, they seem to be working fine and the
asymmetry reappered. Puzzled we started looking into the
normaslization scheme in the analysis code. We found a normalization
error, once it was fixed, the false asymmetry was gone. However,
at the low energy end of the spectrum there is still a significant
asymmetry. This could be due the beam being at a different position (see
the 07/26 shift summary) or cross-talk. We noticed that the encoder
signals were 100 channels wide. We need to reduce these widths and maybe
use a smaller size signal to reduce cross-talk. We took a long run to
study the false asymmetry more precisely, however the disk on blast03
filled up and we lost the root file which saves the accumulated
histograms for asymmetry analysis. After disk cleanup we
took a few small runs. Having solved the false asymmetry problem we decide
to declare an early victory and give the beam back to CCR (at 7:00
AM) since they wanted to do some studies.
-Dipangkar
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