Jul 16, 2015 Calorimetry

Video Conferencing Information

Meeting Time: 11 a.m.

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Participant Direct Lines

• JLab Phone: in CC F326 is 757-269-6460 (usual room)
• JLab Phone in CC L207 is 757-269-7084
• 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. Change BCAL and FCAL coordinates use the global coordinate system (not the target center). Action of this item is under discussion
2. Understand BCAL efficiency estimates (cluster vs enhanced) for m7 and m8 data taking modes (Ahmed) Under active study
3. Provide feedback to Will on shower fragmentation (All)
4. Modify mcsmear to produce digihit outputs (Tegan) Completed and checked in.

References

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

Tentative Agenda

1. Announcements
   • Time for meeting
2. Action Items
3. FCAL Update
4. BCAL Update
5. Calorimetry F250 Firmware Discussions
6. Reconstruction and Simulation
   • Early look at BCAL Clusters https://logbooks.jlab.org/entry/3346051
7. Calibration
8. Any other business
9. Testing

Minutes

Attendees: David, Elton, Jon, Manuel, Mark, Adesh (JLab); Zisis, Ahmed (UofR); Sean (NW); Curtis, Will, Mike (CMU); George (Athens).

1. Announcements
   • Start meetings at 11 am, including BCAL reconstruction meeting.
2. Action Items
3. FCAL Update
   1. Base / firmware (Jon)
      • Updated all firmware and testing on a single strand. Waiting for feedback from Hovanes, which will take about a week.
      • Will need to decide on a timeline and criteria for replacing poor performing bases. There are about 10 that need to be checked.
      • Before changing any hardware, the new firmware will be updated and problems verified.
   2. FCAL efficiency (Jon)
      • Starting to study exclusive omega p event with omega->pi0 gamma for determining FCAL efficiency
   3. Gain calibration. See Log Entry 3346084 (Adesh)
      • Gain calibrations (in ccdb) were determined by minimizing the pi0 width using B=0 runs
      • Nonlinearities (i.e. variation in pi0 mass with energy) were observed
      • Approximate nonlinearity corrections were added to ccdb, but were ineffective, so they have been backed out.
      • This calibration applied to B=not 0 runs result in a pi0 peak ~ 117 MeV, sigma~9 MeV.
      • An electron sample from the B=not 0 runs were used to determine gain constants for 20 < r < 60 cm, and used as a see for further pi0 width minimization. See Log Entry 3345736. The iteration used B=0 runs.
      • Output shows non-linearity for B=0 runs. However, non-linearity is not apparent in the B=not 0 runs.
      • Zisis: Suggest to limit range of fit of two-photon distribution to better reproduce the pi0 peak.
      • -> It appears that the B=0 and B=not 0 runs have different systematics
      • Eugene suggested yesterday to take LED data while ramping the magnet to assess the influence of B field on the pmt response.
      • Will: Suggests to start the pi0 width minimization with the pi0 peak centered on the physical mass. It could be that the fit is being because of the wrong overall normalization.
      • Elton: No pi0 peak is visible in the 500<E<600 MeV photon bin. Why not, and is it due to trigger thresholds. Need to understand this to better plan for more calibration runs next period.
4. BCAL Update
   1. Time-walk (Zisis for Noemi)
      • Noemi has had some issues with generating timing plots. Versioning of gcc, Jana, etc have been resolved, but still nominal monitoring plots show a lack of entries. They are investigating if there is a problem with scale and events falling outside the nominal range.
      • Mark had sent early analysis of timing using LED data. Zisis asked if he used the unified hit quantities? Mark: Could not remember precisely, but thought he might have taken the data from DAQTree, but they should work with unified hit objects.
5. Calorimetry F250 Firmware Discussions
6. Reconstruction and Simulation
   1. Early look at BCAL Clusters https://logbooks.jlab.org/entry/3346051
   2. digiHits (Tegan)
      • Checked in digiHits, so that MC should now produced these objects.
      • Elton: The e-mail implied that with the new code the resulting MC showers would have a gain that was about 3 times too large.
      • Tegan agreed to update the variation=mc of gains to yield the (approximately) correct energy scale. [Note already completed. See e-mail]
7. Calibration
8. Any other business
9. Testing