Difference between revisions of "Apr 6, 2017 Calorimeter"

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# [[GlueX-Collaboration-May-2017|Collaboration Meeting]] May 15-17, 2017
 
# [[GlueX-Collaboration-May-2017|Collaboration Meeting]] May 15-17, 2017
 
# Action Items
 
# Action Items
 +
# Most items are under study.
 
# Activities during the down
 
# Activities during the down
−
# FCAL update
+
#* Adesh will talk to Fernando/Chris/Nick about disabling red light option in Fcal dark room.
 +
# FCAL update (Adesh)
 +
## Pi0 gain calibrations have been completed for spring 2017
 +
##* CCDB has been updated with new calibration constants
 +
##* See a rate dependence to the gain calibration. The periods with low intensity show a pi0 peak at 130 MeV after calibration. Pedestals for these periods are fine. Will investigate with LED data.
 +
##* Non-linearity correction has been determined. A single curve function will do. (2016 data seemed to require a linear and curve function.
 +
## Timing
 +
##* Satellite peaks at 2 ns are not understood.
 +
##* One also sees a time slewing, but the source is unclear. The slewing seems more pronounced when one uses pi0 calibration showers.
 +
##* 4ns shifts in fADC channels have not been established. The plan is to look at LED data. Ahmed: any time shifts are at the percent level, but Sean noted that other systems see a wider issue.
 
# BCAL update
 
# BCAL update
 
# Calibrations
 
# Calibrations
 +
## [https://logbooks.jlab.org/entry/3469116 ADC timing: 4 ns run-to-run shifts in certain BCAL channels] (Mark)
 +
##* Extracted 4 ns shifts channel by channel as a function of run number. This is done by comparing ADC and TDC data.
 +
##* Some channels actually see shifts in both directions (i.e. 3 peaks)
 +
##* The 4 ns shifts affect the extraction of higher level constants, i.e. gain ratio and attenuation lengths.
 +
##* Expects to commit code and tables for the 4 ns shifts later today
 +
##* The present method does not work for layer 4 because there are no TDCs on layer 4. Need to develop another procedure for layer 4.
 +
## [https://logbooks.jlab.org/entry/3469166 BCAL gain drifts: Spring 2017 all runs] (Mark)
 +
##* Plot ln(ADC_up/ADC_down) vs z to extract gain ratio and attenuation lengths.
 +
##* These constants have been determined before the 4 ns shifts, but they are affected by the timing shits, so need to be redone after the 4 ns shifts are corrected.
 +
##* Gain ratios are seen to vary as a function of run number for some channels.
 +
## [https://logbooks.jlab.org/entry/3469362 Stability of LED signal vs rum number for problematic channels] (Ahmed)
 +
##* Ahmed has confirmed that channels identified by Mark have poor stability. The stability is a problem for one side, usually the channel  with lowest gain
 +
##* It has not been decided how to handle these problematic  channels. So far about a dozen have been identified.
 +
##* Will also finds that the problematic channels are showing poor calibrations, which is not surprising since their gain is time dependent.
 +
##* Zisis: Could this be due to the summing circuit? Mark: No clear systematics has been found yet.
 +
##* Andrei: Do the channels show the same behavior at lower bias? Elton: we have been running at Vover=1.4 for over a year and have not investigated long term stability at other settings.
 
## [https://logbooks.jlab.org/entry/3469359 BCAL gain calib] (Will M.)
 
## [https://logbooks.jlab.org/entry/3469359 BCAL gain calib] (Will M.)
−
## [https://logbooks.jlab.org/entry/3469116 ADC timing: 4 ns run-to-run shifts in certain BCAL channels]
 
−
## [https://logbooks.jlab.org/entry/3469166 BCAL gain drifts: Spring 2017 all runs]
 
 
# Reconstruction and Simulation
 
# Reconstruction and Simulation
 
# NIM articles
 
# NIM articles

Revision as of 12:42, 6 April 2017

Video Conferencing Information

Meeting Time: 11:00 a.m.

  1. To join via a Web Browser, go to the page [1] https://bluejeans.com/907185247.
  2. To join via Polycom room system go to the IP Address: 199.48.152.152 (bjn.vc) and enter the meeting ID: 907185247.
  3. To join via phone, use one of the following numbers and the Conference ID: 907185247.
    • 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. Unmuting on a computer is trivial as there is a microphone button than can be clicked.
  5. More information on connecting to bluejeans is available.

Participant Direct Lines

  • JLab Phone in CC L207 is 757-269-7084 (usual room)
  • JLab Phone: in CC F326 is 757-269-6460
  • Phone in the Regina Video-conference Suite is 306-585-4204
  • Athens Phone: in Christina's office is 011-30-210-727-6947

Action Items

  1. Determine number of saturation/underflows that exist in the two LED bias monitoring settings (Ahmed) Working on periods with only one bias
  2. Understand the nature of the peak in the (Fcal propagated to target -RF) satellite peak of -2 ns (Adesh) Under investigation. Will use LED data to investigate this and 4 ns shift in fADCs
  3. Disable red LED string in dark room to avoid leaving it on in the future. (Adesh)
  4. Quantify the LED pulser sector jumps within one run (Ahmed) Investigation of outliers continues under study.

References

  1. FCAL HDFCAL log book
  2. BCAL HDBCAL log book

Tentative Agenda

  1. Announcements
  2. Collaboration Meeting May 15-17, 2017
  3. Action Items
  4. Most items are under study.
  5. Activities during the down
    • Adesh will talk to Fernando/Chris/Nick about disabling red light option in Fcal dark room.
  6. FCAL update (Adesh)
    1. Pi0 gain calibrations have been completed for spring 2017
      • CCDB has been updated with new calibration constants
      • See a rate dependence to the gain calibration. The periods with low intensity show a pi0 peak at 130 MeV after calibration. Pedestals for these periods are fine. Will investigate with LED data.
      • Non-linearity correction has been determined. A single curve function will do. (2016 data seemed to require a linear and curve function.
    2. Timing
      • Satellite peaks at 2 ns are not understood.
      • One also sees a time slewing, but the source is unclear. The slewing seems more pronounced when one uses pi0 calibration showers.
      • 4ns shifts in fADC channels have not been established. The plan is to look at LED data. Ahmed: any time shifts are at the percent level, but Sean noted that other systems see a wider issue.
  7. BCAL update
  8. Calibrations
    1. ADC timing: 4 ns run-to-run shifts in certain BCAL channels (Mark)
      • Extracted 4 ns shifts channel by channel as a function of run number. This is done by comparing ADC and TDC data.
      • Some channels actually see shifts in both directions (i.e. 3 peaks)
      • The 4 ns shifts affect the extraction of higher level constants, i.e. gain ratio and attenuation lengths.
      • Expects to commit code and tables for the 4 ns shifts later today
      • The present method does not work for layer 4 because there are no TDCs on layer 4. Need to develop another procedure for layer 4.
    2. BCAL gain drifts: Spring 2017 all runs (Mark)
      • Plot ln(ADC_up/ADC_down) vs z to extract gain ratio and attenuation lengths.
      • These constants have been determined before the 4 ns shifts, but they are affected by the timing shits, so need to be redone after the 4 ns shifts are corrected.
      • Gain ratios are seen to vary as a function of run number for some channels.
    3. Stability of LED signal vs rum number for problematic channels (Ahmed)
      • Ahmed has confirmed that channels identified by Mark have poor stability. The stability is a problem for one side, usually the channel with lowest gain
      • It has not been decided how to handle these problematic channels. So far about a dozen have been identified.
      • Will also finds that the problematic channels are showing poor calibrations, which is not surprising since their gain is time dependent.
      • Zisis: Could this be due to the summing circuit? Mark: No clear systematics has been found yet.
      • Andrei: Do the channels show the same behavior at lower bias? Elton: we have been running at Vover=1.4 for over a year and have not investigated long term stability at other settings.
    4. BCAL gain calib (Will M.)
  9. Reconstruction and Simulation
  10. NIM articles
  11. Any other business

Minutes

Attendees: Elton, Adesh, Mark (JLab); Sean (NW); Will (CMU); Andrei, Zisis, Ahmed (UofR); Matt (IU); Christina (Athens)

  1. Announcements
  2. Collaboration Meeting May 15-17, 2017
  3. Action Items
  4. Activities during the down
  5. FCAL update
  6. BCAL update
  7. Calibrations
    1. BCAL gain calib (Will M.)
    2. ADC timing: 4 ns run-to-run shifts in certain BCAL channels
    3. BCAL gain drifts: Spring 2017 all runs
  8. Reconstruction and Simulation
  9. NIM articles
  10. Any other business
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