View source for May 6, 2015 Calibration

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GlueX Calibration Meeting<br>
Wednesday, May 6, 2015<br>
11:00 am, EDT<br>
JLab: CEBAF Center, F326<br>

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== Agenda ==

# Announcements
#* [http://argus.phys.uregina.ca/cgi-bin/private/DocDB/ShowDocument?docid=2700 Linear Polarization in Spring Data]
# [[GlueX-Collaboration-May-2015|Collaboration Meeting]]
# Commissioning Data
#* Data quality
#* Mode 7 v. Mode 8
#* Cosmic data
# Subdetector Reports
# Simulations (Sean/Mark I.)
# Calibration Processing
# AOB

== Minutes ==

Attending: Sean (NU); Curtis, Naomi (CMU); Noemi (Regina); Simon, Justin, Paul, Nathan, Alex, Eric, Mark I., Mike S., Will M., Adesh, Mark D., Luke

=== Announcements===

There will be an offline monitoring run for the Fall 2014 and Spring 2015 data sets tomorrow (5/7) at 5 PM EST [time changed in press].  Please have all of your updates in by then.

Justin reviewed his latest results on looking for the effects of linear polarization in the spring data, which look very good.

=== Commissioning Data ===

We reviewed several aspects of the recent data:
* Towards the end of production run 2931, [https://mailman.jlab.org/pipermail/halld-online/2015-May/000626.html a problem was discovered] with the data being reported by the fADC125s.  It affected the files for this run starting with #93.  The problem is still being studied and it is not clear how much other data is affected.
* The data taken in the spring was a mix of readout modes 7 and 8 (without and with waveform information), with the intent of verifying that they give consistent results.  Simon reported that he didn't see any gross differences between the two, though he hadn't looked at the results in detail.  He did notice that in at least one run, ~10% of events had FCAL hits without pedestal information.  Mike found that the error handling for fADC125 mode 7 data in the offline code required some improvements, and checked these in.
* We discussed plans for taking cosmic data.  The consensus was that using the BCAL trigger was fine, and as much data as possible should be taken.  This data would be useful for the BCAL, CDC, FDC (to some extent), and Start Counter.  It is not clear if any other detectors would find cosmic ray data useful.

=== FCAL === 

Adesh presented some preliminary results on FCAL pi0's from Run 2931 with different cluster energy thresholds.  Note that these distributions differ from the monitoring plots only by excluding clusters near the center, which primarily removes a low-energy enhancement near threshold.  Some concerns about the fits shown were raised, since the steeply-varying background could affect the results for fitting the peak, which gives a pi0 mass ~10-20 MeV lower than expected.  Adesh will look at these and update his results for the full spring run.

He also plans to upload some updated FCAL gains, and will write a logbook entry describing what was done.

=== BCAL ===

Will presented some BCAL pi0 plots from the spring run with different energy thresholds. Clear pi0 peaks were seen with consistent masses.  A hint of an eta peak is seen as well, work to reduce the backgrounds in that region is on-going.

The pi0 yield is about 75% of that from the Fall run.  It was suggested to look at the straight track for pi0's as well.

=== CDC ===

Mike is looking at the per-straw efficiency, since there was not enough low-noise data taken to determine the full tracking efficiency.  He and Simon are also looking at the gas mix.  Several methods indicate that the CO2 percentage is ~48%, and the drift tables were updated accordingly.

== FDC ===

Lubomir is working on updating the FDC alignment with the straight track data from the last run.  Simon has added preliminary alignment constants to the CCDB.

=== TOF ===

There was a long discussion about the TOF calibrations at yesterday's meeting. 

#* [http://argus.phys.uregina.ca/cgi-bin/private/DocDB/ShowDocument?docid=2700 Linear Polarization in Spring Data]
# [[GlueX-Collaboration-May-2015|Collaboration Meeting]]
# Commissioning Data
#* Data quality
#* Mode 7 v. Mode 8
#* Cosmic data
# Subdetector Reports
# Simulations (Sean/Mark I.)
# Calibration Processing
# AOB