Difference between revisions of "March 25, 2015 Calibration"

Revision as of 12:04, 26 March 2015

GlueX Calibration Meeting
Wednesday, March 25, 2015
11:00 am, EDT
JLab: CEBAF Center, F326

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Agenda

1. Announcements
2. Subdetector Reports
3. Detector Matching (Paul): Run Browser
4. Spring Calibration Plans
5. Simulations
6. AOT

Minutes

Attending: Sean (NU); Simon, Kei, Paul, Lubomir, Will M., Alex B., Justin, Beni, Mike S., Mark D., Elton (JLab); Naomi (CMU); Noemi (Regina)

Subdetector Reports

• FCAL - No news. Sean will follow up and talk to Matt & John Z. about their skimming needs
• BCAL - When Will looks at 900 MeV showers, he gets a pi0 resolution of 9.5 MeV, although it's statistics limited. Mark D. is looking at the corrections in more detail.
• CDC - Naomi is making progress with her drift time fitting procedure and is working on identifying 50-100 "good straws" to monitor.
• FDC - Lubomir is finishing up his alignment calculations. He has given constants for FDC packages 2-4 to Simon, who is making the necessary changes to the reconstruction code and CCDB. The TDC times are not being currently used in the reconstruction; Lubomir and Simon will discuss this.
  • Naomi mentioned that David has implemented her new fADC125 algorithm in the offline software, and sent out an email with some instructions on how to enable it. She is still making some final checks, and the effects of this algorithm will need to be studied.
• TOF - Sasha is still working with his algorithm, and running into problems dealing with the low signal/background and small statistics of the bars far from the beamline. After the last calibration meeting, Sean, Mark I., Simon, and Beni met together to discuss various other possible calibration methods. Beni had determined some per-channel offsets and gave them to Simon who is studying them. Simon is also working on determining the effective velocities for each bar using hits matched to tracks.

Detector Matching

Spring Calibration Plans

Simulations

A few things still need to be looked at before launching a new set of simulations. Sean will organize the next launch when he is at JLab in April.

Proposed Spring Plans

1. Short-term (few days)
   1. Realign detector times
   2. Compare detector performance to fall run
2. Medium-term (~1-2 month)
   1. Check stability of existing calibrations
   2. Improve timing calibrations
      1. Continue TDC commissioning
      2. RF time calibration
      3. Refine timewalk, etc. corrections
   3. Monitor dependence on conditions (gas mix, temperature, etc.)
   4. Calculate luminosity/normalization factor
      1. Using PS - Kei and Simon will talk to Alex about this
      2. Think up alternate method
3. Long-term (summer)
   1. Improve FCAL/BCAL calibrations
   2. Improve detector alignment
   3. Update digitization and smearing in simulation
   4. Update PID calculations (requires understanding uncertainties)
   5. Calculate luminosity/normalization factor using physics channel (e.g. rho photoproduction)
      1. Requires understanding acceptances, efficiencies

Slides

Talks can be deposited in the directory /group/halld/www/halldweb/html/talks/2015 on the JLab CUE. This directory is accessible from the web at https://halldweb.jlab.org/talks/2015/ .