May 20, 2015 Calibration

GlueX Calibration Meeting
Wednesday, May 20, 2015
11:00 am, EDT
JLab: CEBAF Center, F326

Connection Using Bluejeans

1. To join via Polycom room system go to the IP Address: 199.48.152.152 (bjn.vc) and enter the meeting ID: 630804895.
2. To join via a Web Browser, go to the page [1] https://bluejeans.com/630804895.
3. To join via phone, use one of the following numbers and the Conference ID: 630804895
   • US or Canada: +1 408 740 7256 or
   • US or Canada: +1 888 240 2560
4. Upon connection all microphones are automatically muted. To unmute your mike on a Polycom or equivalent unit, enter *4
5. More information on connecting to bluejeans is available.

Agenda

1. Announcements
   • New Offline Wiki Page
   • Calibration/Reconstruction Uncertainties
2. Subdetector Reports
3. Simulations (Sean/Mark I.)
4. Calibration Processing (Sean)
   • Calibration Train
5. AOB

Minutes

Attending: Sean (NU); Curtis, Naomi (CMU); Mahmoud (FIU); Simon, Kei, Beni, Nathan, Adesh, Mark I., Elton, Eric, Alex B., Fernando, Luke, Eugene, Mike S., Justin, Alex S.

Announcements

• Mark Ito has reorganized the offline software wiki page, and asked for any comments. Naomi suggested adding links to information on making plugins and Subversion.
• Paul M. wanted to remind everyone to work on integrating uncertainties in measurements and calibrations into the reconstruction code and CCDB.
  • Curtis asked if there were templates for calibration uncertainties in the CCDB. Sean said that some detectors have them, some don't. Experience has shown that the most effective procedure is to produce the results and a concrete plan for adding the constants to the CCDB.

FCAL

Adesh reported that he is currently working on estimating the number of pi0's in data. The cuts he is currently using are very tight and he is investigating what happens when they loosen them. He also tried some of the suggestions made in the last calibration meeting for improving his fits to the pi0 spectrum, and is still finding a pi0 mass that is ~10 MeV below the known mass. Such a shift was not seen in the Fall 2014 data.

Another improvement to the analysis is the rejection of clusters matched to charged tracks - this does indeed improve the signal-to-background ratio that is seen. Other analyses in progress include a combined analysis of the Fall and Spring data, and studying electron showers.

BCAL

Elton reported that Will is continuing his pi0 calibration studies, now looking at pi0's with one shower in the BCAL and one in the FCAL. He sees some shifts in energy that may be due to showers that are not entirely continued in the BCAL, and is studying them. George is looking at the effective velocities - he has some preliminary results and he is looking at their systematics.

CDC

Simon is updating his alignment calculations with some recent long cosmic runs. The data definitely seems to be of higher quality than before. In the drift range where the efficiency is flat, he is seeing resolutions of ~100-150 um, with very small residuals. Mike S.'s work on the alternate alignment with Millipede is on-going.

Mike's overall timing calibrations for the spring data are on-going. He's integrated the RF timing reference signal into his procedure, which helps a lot. The higher-rate runs are trickier and need some more analysis.

FDC

Simon has added Lubomir's alignment constants into the CCDB, and is studying their effect. Lubomir is updating these calibrations using Spring data.

TOF

Beni reported on his work on TOF calibrations. His procedure now obtains timing offsets for all paddles, including single-ended ones, and ADC versus TDC timing. He's been looking more at the ADC data - finds the timing isn't bad, though it could use some improvement, and is able to extract some preliminary attenuation corrections. There is still a lot to do, as the histograms have lots of features that are not trivial to understand.

Start Counter

Eric reported that the latest results have been revisiting the propogation correction calculation based on some comments that Matt S. made at the Collaboration Meeting about their fitting method. The fitting procedure has been completely rewritten, and similar results are obtained.

1. • New Offline Wiki Page
   • Calibration/Reconstruction Uncertainties
2. Subdetector Reports
3. Simulations (Sean/Mark I.)
4. Calibration Processing (Sean)
   • Calibration Train
5. AOB