[Halld-cal] Fwd: BCAL in the new year / brainstorm

[Elton Smith]

Hi all,

At the Spring 16 preparation meeting next week, we are asked to report
next week on BCAL
- achievements and problems during fall 2015 run
- preparations needed for spring 2016 run
- goals for the Spring 2016 run

Thoughts/comments on the fall run
- One discriminator was bad and has been replaced. (Need to verify
operation now)
- Environmental monitoring is working well now. We operated at 10 deg C,
but should consider running lower, e.g. chiller at 5 deg C
- The NSB,NSA values were reduced to 0,26. See Log Entry
https://logbooks.jlab.org/entry/3368391. This resulted in a pi0 peak at
about 109.
-- The pi0 peak is probably directly affected by the pulse integral, but
also by assuming the position of the target is at the center of the
hydrogen cell. The solid target was located downstream at the exit of
the start counter. This may also affect the peak position.
-- It would be nice to confirm that we understand the current
normalization, i.e. obtain the correct pi0 peak using the correct target
information.
-- The BCAL pluggins run offline show fairly nice peaks for the pi0, but
they don't have fits, so I don't know how the actual resolution compares
to our previous data.

Items that should be worked on before the next run starts:
- We should check that runs with multiple triggers are correctly
identified. (We had runs this way last spring, but the trigger
information was not being passed on to the analysis. David was working
on this and probably has made the information available, but this needs
to be checked).
- We should also check the inclusion of LED pulser data into production
running. This can be checked before the run starts with cosmic data.
- The software to check the functioning of all the SiPMs before the run
starts only works with the stand-alone DAQs. We need to rewrite the code
to accommodate data taken with the TS.

Goals for the next run:
- Systematic studies of resolution: dependence of pi0 resolution and
peak position on z-position of showers, energy and angle dependence of
resolution,
- Study eta peak and compare with expectations

Ongoing projects:
- Comparison of MC with data. Adjust MC so that it matches the data and
can be used with confidence for various systematic studies.
- The cluster finding / shower reconstruction needs to be optimized.
- Michel electrons, understanding threshold effects in BCAL.
- Complete set of calibration constants for BCAL, including time-walk
corrections. Check timing of TDCs, look at time-of-flight.
- Understand the efficiency, differences between mode 8 and mode 7 running.

We can discuss some of these questions tomorrow at the reconstruction
meeting.

-- 
Elton Smith
Jefferson Lab MS 12H3
12000 Jefferson Ave STE 4
Newport News, VA 23606
(757)269-7625
(757)269-6331 fax