[d2n-analysis-talk] BB peds

[posik at jlab.org]

 Hi all,

   I have been working on documenting the Big Bite Cerenkov pedestal
shifts and correcting them for in the DB. We had two different ADC
modules during our running (v792,1881). I have finished listing the ped
values and implemented them in my local DB for the v792, and am just
about done testing them. I am a good 1/3 of the way through the 1881
ADCs. I should have the updated DB out by Tuesday.

During this ped correction period, I found it helpful to create a list of
Big Bite runs and the current that the run had. This document can be found
here:

http://www.jlab.org/~posik/d2n/d2n_run_current.txt

And is on the d2 wiki. For this list I just took the end of run average u3
bcm as the current for that run (this is not an absolute current, just an
idea).

 Also during our running we had 5 HV changes on the BB cerenkov. Right now
only HV #4 and 5 have the one photo peak calibrated. This is due to the
fact that I could only find LED runs for those two voltages. However, now
that they are calibrated, I can use them to calibrate the other 3 HVs. I
am going to do this by plotting the corrected ADC for HV#4 or 5, get the
peak value. Then I will plot the ped subtracted ADC for HV 1-3 and
multiply by some factor to get the HV 1-3 ADC peaks to match the ADC
peaks from HV 4,5.


-Matt