Summary: Juggling cables at the FE amplifier seems to have 'solved' the intermittent noise problem on PMTs 2,3. PMTs 1--10 (beamline side) gain matched to put peak at ADC channel 30.
Trigger T2 was restored to be the Cer+Sh overlap trigger. ADC gate timing with this trigger was double checked at the Cerenkov PMTs. Looks good.
Run 4910:
- HVs for 1--10 on, pulser on
- LED #16, #20 plugged in
- Pulser amplitude sent to LED is 1.25V, 25ns wide
- Pedestal run
- T8 trigger dominated (others prescaled away)
= Pedestals mostly OK
- still noise on ADC chans 1,2
- similar noise on ADC chans 17,18. Those PMTs are powered off right now
- this noise was NOT there yesterday...
Run 4911:
- identical config to 4910
= same results as 4910
Run 4912:
- HVs for 1--10 on, pulser on
- cables to LED #16, #20 have been unplugged
- No LEDs are being powered right now.
= same noise as runs 4910--11
[ Lots of F1 FIFO overflow errors on replay this afternoon.
- tried power cycling ROC5 crate -- didn't help ]
Run 4913:
- same config as 4912, but ROC5 was rebooted
- HVs for 1--10 on, pulser on
= same results
Run 4914:
- same config as 4912
- tried reseating the cables for those PMTs at the amplifier (since we had
looked at the signal from PMT 16,17 earlier today)
= same results
Run 4915:
- HVs for 1--10 on, pulser on
- pedestal run using LED pulser trigger
- NOTE: cables to LED #16, #20 are still unplugged
- No LEDs are being powered right now.
- changed prescales so the DAQ is triggered on the pulser-driven T2 trigger now
= same results as with T8 trigger (good)
- noise still there though...
Run 4916:
- HVs for PMTs 1--10 on, pulser on
- cables to LED #16, #20 plugged back in. LEDs are firing now
- Pulser amplitude sent to LED is 1.25V, 25ns wide
= after run we adjusted HVs on PMTs 5,7--10
- PMTs 1,4,6 look good
- PMTs 2,3 (noisy) are hard to tell
Run 4917:
- HVs for PMTs 1--10 on, pulser on
- Pulser amplitude sent to LED is now 1.35V, 25ns wide
= after run we adjusted HVs on PMTs 5,7--10
- PMTs 1,4,6 look good
- PMTs 2,3 (noisy) are hard to tell
Run 4918:
- HVs for PMTs 1--10 on, pulser on
- Pulser amplitude sent to LED is 1.35V, 25ns wide
= after run we adjusted HVs on PMTs 5,9--10
- PMTs 1,4,6,8 look good
- PMTs 2,3 (noisy) are hard to tell
Run 4919:
- HVs for PMTs 1--10 on, pulser on
- Pulser amplitude sent to LED is 1.35V, 25ns wide
= after run we adjusted HVs on PMT 4
- PMTs 1,5--10 look good
- PMTs 2,3 (noisy) are hard to tell
Run 4920:
- HVs for PMTs 1--10 on, pulser on
- Pulser amplitude sent to LED is 1.35V, 25ns wide
= PMTs 1,4--10 look good
- PMTs 2,3 (noisy) are hard to tell
Run 4921:
- HVs for PMTs 1--10 on, pulser on
- Pulser amplitude sent to LED is 1.35V, 25ns wide
- Moved the signal cable for PMT 2 from its amplifier channel and plugged it
into that for PMT 11 (different amplifier, different crate)
= Noise on ADC ch 1,2 is now gone.
- ADC ch 1 (no signal now) has sharp, good pedestal
- ADC ch 2 (PMT 3) looks quite good
- ADC ch 10 (PMT 2) looks quite good
Run 4922:
- HVs for PMTs 1--10 on, pulser on
- Pulser amplitude sent to LED is 1.35V, 25ns wide
- signal cable for PMT 2 from its amplifier channel is still in that for PMT
11 (different amplifier, different crate)
- unplugged top ribbon cable from F1 TDC in ROC5, slot 11 to see if the F1
overflow errors went away
= Overflow errors did NOT go away
Run 4923:
- HVs for PMTs 1--10 on, pulser on
- Pulser amplitude sent to LED is 1.35V, 25ns wide
- signal cables for PMT 2 are now plugged into an unused channel in its original
amplifier
- PMT 11 is restored
- plugged top ribbon cable back in, removed _bottom_ ribbon cable from F1 TDC
in ROC5, slot 11 to see if the F1 overflow errors went away
= Overflow errors DID go away
- PMTs 2,3 both look good now.
- noise on ADC channels for PMTs 18,19 is gone now too...
Run 4924:
- HVs for 1--10 on, pulser on
- Pedestal run again
- T8 trigger dominated (others prescaled away)
= all noise still gone, all peds look good
Run 4925:
- HVs for PMTs 1--10 on, pulser on
- Pulser amplitude sent to LED is 1.35V, 25ns wide
- (Now gain check PMTs 2,3)
= Raised HV on PMT 3
- PMT 2 is good
Run 4926:
- HVs for PMTs 1--10 on, pulser on
- Pulser amplitude sent to LED is 1.35V, 25ns wide
- (Now gain check PMT 3)
= lowered HV on PMT 3
Run 4927:
- HVs for PMTs 1--10 on, pulser on
- Pulser amplitude sent to LED is 1.35V, 25ns wide
- (Now gain check PMT 3)
= lowered HV on PMT 3
Run 4928:
- HVs for PMTs 1--10 on, pulser on
- Pulser amplitude sent to LED is 1.35V, 25ns wide
- (Now gain check PMT 3)
= PMT 3 is now OK