[Halld-pid] Configuration of TOF ADCs and TDCs

[Alexander Ostrovidov]

I have noticed 2 problems while looking at the TOF data from run 995:

1) Only fADC times are in sync with the trigger. TDC times
seems to be completely random and unrelated to the trigger time
or to fADC hits. It looks like the change in the trigger latency (when
switching from the TOF standalone trigger to the current FCAL trigger)
was accounted for only in the FADC250 configuration. fADC latency
has been changed from 510 to 910 samples (or from 2040 ns to 3640 ns).
TDC1290 latency still remains at the same 2000 ns value as before.
I think, config parameter TDC1290_W_OFFSET also needs to be 
adjusted from -2000 to -3600. What I'm not sure about is if the current 
config file 'fcal_all_891a.conf' is the only place to make such change, 
or if there is some more generic template used to generate new config
files from. Can DAQ experts make sure that this change will not be 
lost in the future config files as well?

2) I had a very stable fADC pedestals during cosmic runs, with a 
baseline mean value right on spot at 200 counts for all channels. However, 
the mean pedestals in the current data have a spread from 190 to 206 
counts from channel to channel. I also noticed that my latest calibration
(/gluex/Subsystems/TOF/parms/common/fadc250/roctof1_fadc250_ver1.cnf)
has DAC values which are like 60-80 units lower than the current values in
/gluex/CALIB/ALL/fadc250/roctof1_fadc250_Run_891.cnf.
This is a large difference in the DAC old and new calibrations and should 
result in a large baseline difference as well. However, the current baselines
are still in the vicinity of 200 with the new DAC values the same way they
were at 200 with the old values in the past. So, something has changed
from then to now which required large readjustment of DACs. But I
don't have a clue what has changed actually. Does anyone know?

More importantly, what do we do with the current 190-to-206 large spread
of the baselines? Does tis means we need to recalibrate FADC250 again
more carefully this time?

Sasha