http://hallaweb.jlab.org/experiment/E05-007/meetings/commissioning/run_4788/ http://hallaweb.jlab.org/experiment/E05-007/meetings/commissioning/run_25244/
These two runs were taken last night with both HRS magnets on except right arm Q2. On both arms, not all lead glass blocks have been aligned yet, so the ADC spectrum are everywhere. Spotted many possible problems and will report at the meeting today:
1) Left arm fbTDC PS and TS triggers do not look "clean", except group 3 and PS from group 4-6. Not sure if this is because of too low threshold in the discriminator or other reasons.
2) Left arm VETO signals are about 100ns behind all PS and TS triggers. This is causing no physics trigger (electron or pion).
3) Right arm PS and TS trigger timing looks different from June test runs. Many of them are much wider.
4) Right arm PS cuts look much higher than June test runs. It is now around channel 1000, vs. ~400 in June. see for example run_4788/R_group2_PSvsSH.pdf. Is it possible the thresholds are set too high?
5) Right arm Cherenkov trigger does not show any cut on the adc sum spectrum. In principle, when cutting on "GC only" fbTDCs, should see a clear cut.
6) Right arm Cherenkov trigger in fbTDC seems to be 100ns later than where it was in June. Interestingly, the electron VETO signal looks normal and at the same position as T1. Could the GC signal being set to "1" at the input of the VETO circuit?
7) Right arm: There is NO pion VETO (SC.and.(.not.)GC). Again this looks like the GC input is being set to one in the VETO circuit.
8) Because of unaligned lead glass outputs, cannot study threshold or PID yet.
7) As listed above, suspect discriminator thresholds not set correctly on
both arms, TS and PS. Or some 740/628Fs have large offsets. Kai is down
in the hall to check this.