Difference between revisions of "Jan 9, 2020 Calorimeter"

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(Minutes)
 
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= Action Items =
 
= Action Items =
 
[[Short term items]]:
 
[[Short term items]]:
# Proposal for updating BCAL gain constants 2019 / extrapolation to higher energy (Karthik)
+
# <strike> Proposal for updating BCAL gain constants 2019 / extrapolation to higher energy (Karthik) </strike> See minutes
 
# Systematically fix labels on FCAL crates (Colin/Elton)
 
# Systematically fix labels on FCAL crates (Colin/Elton)
 
# Ship back bases to IU that fail repair (Colin)
 
# Ship back bases to IU that fail repair (Colin)
Line 51: Line 51:
 
## BCAL
 
## BCAL
 
# Calibrations
 
# Calibrations
#* Quick look at a few pull distributions (Jon)
+
#* [https://halldweb1.jlab.org/wiki/index.php/File:QuickPeekPhotonPulls.pdf Quick look] at a few pull distributions (Jon)
# Monitoring-  
+
#* [https://halldweb.jlab.org/wiki/index.php/File:Nonlinearity_Study.pdf Nonlinearity correction studies] An update (karthik)
 +
# Monitoring
 +
# Reconstruction (Mark)
 +
#* post processing (non-linearity, covariance matrices)
 
# Efficiencies
 
# Efficiencies
 
# Simulations
 
# Simulations
#* Geant4 BCAL reconstructed energy bad in runs < 40000? See github issue [https://github.com/JeffersonLab/HDGeant4/issues/138 here]
+
#* Geant4 BCAL reconstructed energy bad in runs < 40000? See github issue [https://github.com/JeffersonLab/HDGeant4/issues/138 here] (Jon)
 
# NIM articles
 
# NIM articles
 +
#* [https://halldweb.jlab.org/doc-private/DocDB/ShowDocument?docid=3111 GlueX-doc-3111] (Mark)
 
# Any other business
 
# Any other business
  
 
= Minutes =
 
= Minutes =
''Attending:
+
''Attending: Elton, Mark, Varun, Jon (Jlab); Christina (Athens); Churamani, Tolga (FIU); Zisis, Karthik, Ahmed (Regina); Curtis (CMU); Matt (IU).
 +
 
 +
# Announcements
 +
#* [[GlueX-Collaboration-Feb-2020|Collaboration Meeting]] February 13-15, 2020.
 +
#* Beam is imminent, but no consistent delivery yet.
 +
# Action Items
 +
#* Need to find out from Colin if bases have been shipped out.
 +
#* Elton will work with Colin to try to implement a plan to upgrade FCAL labeling.
 +
#* Elton talked to the electronics group to get FCAL spares. Will check they have been ordered.
 +
# Run Updates
 +
## FCAL
 +
##* Matt: Colin reports that the FCAL is ready.
 +
## BCAL
 +
##* Elton: BCAL is ready for beam
 +
##* Mark: From occupancy plots, we find that TDC channels wander in time. Scans of the threshold are used to set the threshold above baseline.
 +
##* Elton: Beni has found that setting the FADC baseline on the TOF channel affects the offsets in the TDCS. This is expected since the splitters are passive. We could investigate if there is any coupling in the BCAL system.
 +
##* All BCAL fans are set to 4000 rpm. Will stay that way until we check stability during the run. Mark checked that the sparcification threshold is set per crate and not on a channel-by-channel basis.
 +
# Calibrations
 +
## [https://halldweb1.jlab.org/wiki/index.php/File:QuickPeekPhotonPulls.pdf Quick look] at a few pull distributions (Jon)
 +
##* Checked pull distributions for geant4 simulations and compared to covariances computed in 2017 with geant3.
 +
##* Checking using gp -> gg p. The comparison between the two simulations is good, means ~ 0.1 (some up to 0.3), sigmas ~ 1.1
 +
##* Other reactions checked. The reaction gp -> g pi+ pi- p stands out with mean ~0.7, sigma~1.4 and very asymmetric.
 +
##* It is likely that this distribution is being distorted by gp -> rho p, with a splittoff included into the fit.
 +
##* Elton: Suggest to use gp -> gg pi+ pi- p to select more common reaction (such as omega).
 +
##* Curtis: Has the shifted vertex been included into the geant4 simulation? Curtis seemed to recall that this was put into the beam parameters methods. We need to check on this.
 +
##  [https://halldweb.jlab.org/wiki/index.php/File:Nonlinearity_Study.pdf Nonlinearity correction studies] An update (karthik)
 +
##* Karthik has updated ccdb with new spring 2019 gain calibrations and a non-linearity correction that uses the same algorithm as in 2018.
 +
##* Most of the slides attempt to develop a method to extend the determination of the non-linearity correction to higher energies using asymmetric pi0 decays.
 +
##* An iterative algorithm suggested by Elton and Mark was implemented but it does not seem like it is converging.
 +
##* Elton is investigating a toy MC that could be useful in understanding the iterative procedure.
 +
##* Elton and Karthik will take this offline and think through the algorithm to evaluate the non-linearity.
 +
# Monitoring
 +
# Reconstruction (Mark)
 +
#* post processing (non-linearity, covariance matrices)
 +
# Efficiencies
 +
# Simulations
 +
#* Geant4 BCAL reconstructed energy bad in runs < 40000? See github issue [https://github.com/JeffersonLab/HDGeant4/issues/138 here] (Jon)
 +
#* Jon has been investigating the reason for very skewed energy distributions in geant4 and run ranges < 40000. It appears that geant3 is ok, and major discrepancies are eliminated for geant4 for runs > 40000.
 +
#* Jon will get back to investigating this issue.
 +
# NIM articles
 +
#* [https://halldweb.jlab.org/doc-private/DocDB/ShowDocument?docid=3111 GlueX-doc-3111] (Mark)
 +
# Any other business

Latest revision as of 16:35, 9 January 2020

Meeting Time: 2:00 p.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

References

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

Goals for Calorimetry Group

  1. Determine preliminary photon reconstruction efficiencies as a function of E, phi and theta in data and simulation with a point-to-point precision of at least 5%.
  2. Measure systematics of pi0/eta mass calibration as a function of detector position to a precision of at east 5 MeV.
  3. Demonstrate agreement of photon reconstruction efficiency and resolution between data and simulation as a function of E, phi and theta to within 5%.

Action Items

Short term items:

  1. Proposal for updating BCAL gain constants 2019 / extrapolation to higher energy (Karthik) See minutes
  2. Systematically fix labels on FCAL crates (Colin/Elton)
  3. Ship back bases to IU that fail repair (Colin)
  4. Order spare FCAL electronics (Elton)
  5. Complete Calorimeter work packages

Long term items:

  1. From Mike's work: -cos(phi) type dependence in the data and a phi dependence at the downstream end of the bcal. See Sep 21, 2017 Calorimeter Meeting.
  2. FCAL: It has been noticed that the pi0 mass shifts when the LED pulser runs at high rate. This is still not understood. See Log Entry 3595928 and references. Several runs have been taken in raw mode. These runs exhibit the shift in pi0 mass with LED running at 1 kHz. There is a need to analyze these to try to determine the cause:
    1. 50634 - FCAL Green LED: 1kHz, 29 V, Livetime is 9%, 1.7 M events
    2. 50635 - FCAL Violet LED: 1kHz, 22 V, Livetime is 9%, 1.4 M events
    3. 50636 - FCAL Blue LED: 1kHz, 15 V, Livetime is 9%, 1.5 M events

Tentative Agenda

  1. Announcements
  2. Action Items
  3. Run Updates
    1. FCAL
    2. BCAL
  4. Calibrations
  5. Monitoring
  6. Reconstruction (Mark)
    • post processing (non-linearity, covariance matrices)
  7. Efficiencies
  8. Simulations
    • Geant4 BCAL reconstructed energy bad in runs < 40000? See github issue here (Jon)
  9. NIM articles
  10. Any other business

Minutes

Attending: Elton, Mark, Varun, Jon (Jlab); Christina (Athens); Churamani, Tolga (FIU); Zisis, Karthik, Ahmed (Regina); Curtis (CMU); Matt (IU).

  1. Announcements
  2. Action Items
    • Need to find out from Colin if bases have been shipped out.
    • Elton will work with Colin to try to implement a plan to upgrade FCAL labeling.
    • Elton talked to the electronics group to get FCAL spares. Will check they have been ordered.
  3. Run Updates
    1. FCAL
      • Matt: Colin reports that the FCAL is ready.
    2. BCAL
      • Elton: BCAL is ready for beam
      • Mark: From occupancy plots, we find that TDC channels wander in time. Scans of the threshold are used to set the threshold above baseline.
      • Elton: Beni has found that setting the FADC baseline on the TOF channel affects the offsets in the TDCS. This is expected since the splitters are passive. We could investigate if there is any coupling in the BCAL system.
      • All BCAL fans are set to 4000 rpm. Will stay that way until we check stability during the run. Mark checked that the sparcification threshold is set per crate and not on a channel-by-channel basis.
  4. Calibrations
    1. Quick look at a few pull distributions (Jon)
      • Checked pull distributions for geant4 simulations and compared to covariances computed in 2017 with geant3.
      • Checking using gp -> gg p. The comparison between the two simulations is good, means ~ 0.1 (some up to 0.3), sigmas ~ 1.1
      • Other reactions checked. The reaction gp -> g pi+ pi- p stands out with mean ~0.7, sigma~1.4 and very asymmetric.
      • It is likely that this distribution is being distorted by gp -> rho p, with a splittoff included into the fit.
      • Elton: Suggest to use gp -> gg pi+ pi- p to select more common reaction (such as omega).
      • Curtis: Has the shifted vertex been included into the geant4 simulation? Curtis seemed to recall that this was put into the beam parameters methods. We need to check on this.
    2. Nonlinearity correction studies An update (karthik)
      • Karthik has updated ccdb with new spring 2019 gain calibrations and a non-linearity correction that uses the same algorithm as in 2018.
      • Most of the slides attempt to develop a method to extend the determination of the non-linearity correction to higher energies using asymmetric pi0 decays.
      • An iterative algorithm suggested by Elton and Mark was implemented but it does not seem like it is converging.
      • Elton is investigating a toy MC that could be useful in understanding the iterative procedure.
      • Elton and Karthik will take this offline and think through the algorithm to evaluate the non-linearity.
  5. Monitoring
  6. Reconstruction (Mark)
    • post processing (non-linearity, covariance matrices)
  7. Efficiencies
  8. Simulations
    • Geant4 BCAL reconstructed energy bad in runs < 40000? See github issue here (Jon)
    • Jon has been investigating the reason for very skewed energy distributions in geant4 and run ranges < 40000. It appears that geant3 is ok, and major discrepancies are eliminated for geant4 for runs > 40000.
    • Jon will get back to investigating this issue.
  9. NIM articles
  10. Any other business