PMT 17 is pretty noisy. (Been true for a while. We didn't want to swap it out since it will require a longish down to flush the entire Cerenkov tank.)
HVs for PMTs 2*,4,8,9,10,12* were tweaked.
(*) changed by >50V
Previous HVs recorded here (run 1810):
http://www.jlab.org/~adaq/halog/html/0902_archive/090225223803.html
New HVs can be found here (run 1841):
http://www.jlab.org/~adaq/halog/html/0902_archive/090226170318.html
Run 1829:
- HVs for 1--10 on, pulser on
- LED #11, #15, #20 plugged in
- LED drive pulse ampl. set to provide 1--2 p.e. pulse on the scope
for PMT 10
- Pedestal run
- T8 trigger dominated (others prescaled away)
= peds: 483, 407, 398, 479, 543, 499, 603, 527, 460, 465
Run 1830:
- HVs for 1--10 on, pulser on
- LED #11, #15, #20 plugged in
= aligning 1--8 to pedestal + 30
= aligning 9--10 to pedestal + 60 (since they are not split)
= adjusted PMTs 2,3,4,8
= adjusted PMTs 9, 10
Run 1831:
- HVs for 1--10 on, pulser on
- LED #11, #15, #20 plugged in
= adjusted PMT 4
Run 1832:
- HVs for 1--10 on, pulser on
- LED #11, #15, #20 plugged in
= adjusted PMT 4
Run 1833:
- HVs for 1--10 on, pulser on
- LED #11, #15, #20 plugged in
- raised LED drive voltage a bit to enhance 2 p.e. peaks
= looks OK
Run 1834:
- HVs for 11--20 on, pulser on
- LED #1, #5, #10 plugged in
- adjusted LED drive voltage for this LED group
- Pedestal run
- T8 trigger dominated (others prescaled away)
= peds: 303, 425, 515, 578, 579, 443, 410, 542, 329, 412
Run 1835:
- HVs for 11--20 on, pulser on
- LED #1, #5, #10 plugged in
= adjusted 12
Run 1836:
- HVs for 11--20 on, pulser on
- LED #1, #5, #10 plugged in
- LED drive was too large, lowered
= 12 good
Run 1837:
- HVs for 11--20 on, pulser on
- LED #1, #5, #10 plugged in
- LED drive was still too large for some of the PMTs, lowered it again
= Gains look pretty good.
= PMT 17,18 have much noisier pedestals than the rest, will investigate
that
now.