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

[Fernando J Barbosa]

Hi Elton,

The discriminator in question, the first to "fail", will be tested soon. 
However, the cause may be related to:
a) there was a metal shaving found at the time of replacement
b) the fans were being controlled and operating under 2,500 RPM (none 
should be the case).

Considering additional tasks for the upcoming run, I would like to 
request the following:
A) monitor fADC250 pedestals for every channel in a crate (may do all 
crates if possible) w/ fan speeds at 4,000 RPM (no PID loop control)
B) as above w/ PID loop control (3,000 to 6,000 RPM)
C) average pedestal per crate for A and B above.

If time permits:
D) active pedestal correction via DACs
E) investigate dithering algorithms.

Best regards,
Fernando



On 1/7/2016 10:57 AM, Elton Smith wrote:
>
> 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.
>

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