Mar 9, 2017 Calorimeter

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Video Conferencing Information

Meeting Time: 10:00 a.m.

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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. Update shift information for Fcal (Jon) Draft pages updated. Elton has provided comments.
  2. Determine number of saturation/underflows that exist in the two LED bias monitoring settings (Ahmed)
  3. Understand the nature of the peak in the (Fcal propagated to target -RF) satellite peak of -2 ns (Adesh)
  4. Check with Mark and Sean regarding status/plans for low level BCAL calibrations (Elton)

References

  1. FCAL HDFCAL log book
  2. BCAL HDBCAL log book
  3. BCAL Action Items and Working Tasks

Tentative Agenda

  1. Announcements
  2. Action Items
  3. Run preparations
    1. LED Monitoring
  4. FCAL update
  5. BCAL update
  6. Calibrations
    1. pi0 calibrations
    2. Timing calibrations
    3. Pi0 Dalitz decays
    4. e clusts [2]
  7. Reconstruction and Simulation
  8. NIM articles
    1. BCAL
      • Organization: I have changed names of files. Also, I have deleted the .pdf file of the document. There are pros and cons to this. Pro: You can take a look at the .pdf directly from the repository. Con: It seems like there are always conflicts generated by the .pdf because of non-essential differences between local versions and those in the repository, which is annoying. Anyway, for now the .pdf is not checked in, but can be added easily if we want to do this.
      • authors: JLab: I think we should add Fernando, Nick and Chris for all the work on Bcal electronics and maintenance. Tim for coordinating all the mechanical issues. USM: They played a substantial role in qualifying the MPPCs, fabricating the light guides, and electronic design and software development for the LED pulsing system.
      • Introductory material: I have moved various material around and modified the section names: Project Background and Detector Requirements / Overview and Design. Some of the details of the description that was in the introduction has been moved to appropriate specific sections, e.g. the SiPM section.
      • Edits (minor): Fibers and Matrix construction
      • Added: Sections on Light Collection / Photo Sensors / Electronics (new). These combine material from 'segmentation' and 2012 beamtest.
      • BCAL_nim.bib file: Modified with additional references, but clearly these will need to be worked on systematically once most of the document is available.
      • I might have too much material in these new sections and they will likely be culled. So far the goal has not been to produce final text, but just gather info and see how the whole fits together.
      • General: Overall, these sections have mostly text and only a few figures ("a figure is worth a thousand words"). This may be ok, since they often refer to other documents, but we can revisit this once most of the sections are filled in.
  9. Any other business

Minutes

Attendees: Elton, Mark, Will, Adesh (JLab); Zisis, Ahmed (UofR); George (Athens); Matt (IU)

  1. Announcements
  2. Action Items
  3. Run preparations
    1. BCAL
      • LED pulser lost its pulsing sequence last week. First time we have seen this. Rebooting and restarting the python script seemed to fix the problem. We need to keep an eye out for this. Next time we can investigate sources of problems: first reboot IOC, then restart python script to find source.
    2. FCAL
      • fADC board went bad and has been replaced. Symptom was that pedestals gave errors and DAQ values could not be set.
      • Tuesday (Feb 28) the red LED lights were left on in the dark room. Shift crew noticed high pedestal shifts. Need to find a solution to disable red LED string after run is over.
    3. LED Monitoring
      • Log Entry 3463466
      • Elton has been working with Ahmed to streamline the LED monitoring program. Elton developed an algorithm that selects configurations using the trigger bit, which specifies up/down LED and cuts down the unknown configurations by a factor of 2. Ahmed is comparing the two approaches and will be sorted out offline.
      • We see some of the sector-based systematics this spring, that were seen previously. However, the jumps by sector are of order 0.2-0.5%. These can be adjusted in software if necessary. However, Fernando has put forward a mechanism for this to happen: the LED bias is distributed one sector at a time and the voltage is fed back from this point. From the distribution panel to the BCAL module, it is possible that changes in resistance of the cables could affect the voltage drop and generate a systematic shift. Temperature changes are expected to be slow, although Ahmed has seen changes within one run.
      • Ahmed is looking at outliers as a function of run. At least in one instance, it seems that a particular run seems to be bad and contributing to the large rms of one channel.
      • Ahmed is finding some differences between his selection and Elton's configuration identification. They will need to sort this out and converge on an agreed procedure.
  4. FCAL update (Ahmed)
    • Waiting for skim files for this run, which should be completed this weekend.
    • Investigating differences in energy resolution between MC and data. Matt: Believe that the extraction of the dE/E resolution from the pi0 mass width has been oversimplified because it ignores the fact that energies of two photons are being measured. Error propagation will be checked and may bring expectation closer to measured values.
  5. BCAL update
  6. Calibrations
    1. Timing calibrations
      • Mark: position calibrations, gain ratio and attenuation should be completed today or tomorrow.
    2. pi0 calibrations
      • Will: Pi0 mass width minimization will be done once the low-level calibrations are complete.
      • Tegan is working with Will to take over the pi0 calibration. He is confident that he can use the code. The plan for spring is to have both of them do calibrations and compare results. Tegan will take over the calibration this fall.
      • Documentation is being updated to cover any questions raised during this transition.
      • Will noticed that the pi0 mass started out at about 133 MeV, but fell to about 128 MeV after about R30818. Calibrations?
    3. Pi0 Dalitz decays (George)
      • Moving from genr8 to geant4. The gen_pi0 program is also now working. Geant4 should decay pi0->e+e-g exclusively.
      • George showed some plots based on the previous genr8 simulations. (Geant4 programs should complete later today. George actually showed some plots hot off the press before the end of the meeting].
      • The main discrepancy between data and MC could be seen in the e+e- invariant mass distribution. The differences seemed to be smaller for the small-statistic sample of the geant4 events shown at the end of the meeting.
    4. e clusts [3] (Will)
      • During the collaboration meeting, Lubomir showed large discrepancies between the Fcal energy measurement and the track momentum.
      • Will investigated some event from the sample by scanning them with hdview2. With limited statistics, he concludes that the clusterizer seems to be working as expected and would not eliminate the discrepancy. Many hits on the periphery of the shower might not be included in the clusterizer, but not enough to show 50% differences. Also, did not see evidence for fADC saturation in either Fcal or Bcal. Preliminary conclusion is that calorimetry response seems to be ok. Is tracking the problem? Will investigate this further with higher statistics in 2017.
      • Mark: It might be useful to have an EVIO skim of high energy events in Fcal and Bcal.
  7. Reconstruction and Simulation
    • Paul's e-mail about DBCALGeometry
    • Mark will coordinate with Paul. [Note added: Mark talked to Paul and Sean is making appropriate changes and will keep Mark in the loop to provide input.]
  8. NIM articles
    1. BCAL
      • Organization: I have changed names of files. Also, I have deleted the .pdf file of the document. There are pros and cons to this. Pro: You can take a look at the .pdf directly from the repository. Con: It seems like there are always conflicts generated by the .pdf because of non-essential differences between local versions and those in the repository, which is annoying. Anyway, for now the .pdf is not checked in, but can be added easily if we want to do this.
      • authors: JLab: I think we should add Fernando, Nick and Chris for all the work on Bcal electronics and maintenance. Tim for coordinating all the mechanical issues. USM: They played a substantial role in qualifying the MPPCs, fabricating the light guides, and electronic design and software development for the LED pulsing system.
      • Introductory material: I have moved various material around and modified the section names: Project Background and Detector Requirements / Overview and Design. Some of the details of the description that was in the introduction has been moved to appropriate specific sections, e.g. the SiPM section.
      • Edits (minor): Fibers and Matrix construction
      • Added: Sections on Light Collection / Photo Sensors / Electronics (new). These combine material from 'segmentation' and 2012 beamtest.
      • BCAL_nim.bib file: Modified with additional references, but clearly these will need to be worked on systematically once most of the document is available.
      • I might have too much material in these new sections and they will likely be culled. So far the goal has not been to produce final text, but just gather info and see how the whole fits together.
      • General: Overall, these sections have mostly text and only a few figures ("a figure is worth a thousand words"). This may be ok, since they often refer to other documents, but we can revisit this once most of the sections are filled in.
    2. FCAL
      • Skeleton of paper has been added to git.
  9. Any other business