January 28, 2015 Calibration
GlueX Calibration Meeting
Wednesday, January 28, 2014
11:00 am, EDT
JLab: CEBAF Center, F326
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- Software Review, February 10-11, 2015
- Collaboration Meeting February 19-21 at Jefferson Lab
- Timing Offset Calibrations (Mike S.)
- REST data status (Justin)
- Calibration status/updates
- Start Counter
- Calibration Dashboard
- Data Monitoring
Attending: Sean (NU); Simon, Mike S., Paul, Mark I., Mark D., Nathan, Adesh, Eric, Alex B., Will M., Lubomir, Eugene, Beni, Kei (JLab); Curtis, Naomi (CMU); Justin (MIT); Mahmoud (FIU); Andrei (Regina)
Timing Offset Calibrations
Mike Staib gave a report on his work on automatically calculating timing offsets for the whole detector. This procedure leverages the tracking information, and takes into account the correlations. He starts with all time offsets set to zero, first does a rough timing alignment on the calibrated hit objects, then does a rough calibration of the TDC times with respect to the ADC times, and finally uses negative tracks to calculate offsets relative to the start counter time and derive a finer calibration (in some cases, per-channel). He gets calibrations that looks as good as those currently in the CCDB, sometimes better. For example, the start counter timing resolution for his example run was reduced from 1.4 ns to 1.1 ns, and a larger number of tracks were reconstructed.
There was some discussion about how to best structure this effort. This plugin gives a good start on timing calibrations, but the ultimate calibrations should be done by the detector groups which have the best understanding of their detector. Either Mike's procedure will need to be modular enough so that other people can contribute, or more refined efforts can build on top of these calibrations. A major open question is how interdependent these calibrations are, e.g., if a small epsilon change in one detector necessarily means that we need to recalibrate all subsystems.
- tools for submission of constants to central CCDB
- tests with other runs for stability and robustness of calibrations
- monitoring of results