BCAL Reconstruction Meeting 2015-08-20

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Video Conferencing Information

Meeting Time: 11:00 a.m. EDT

  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: (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 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


  1. BCAL Reconstruction Issues
  2. BCAL Reconstruction Algorithms
  3. Will's reconstructed energy info

Action Items

  1. F250 discussion: peak value into higher level objects (Elton)
  2. Make MC plots that show E vs Egen and resolution (Tegan, Zisis)
  3. Determine up/down gain ratios for spring data (Mark)
  4. Low priority items
    1. z-coordinate determination from up/down amplitude ratio
    2. Sampling fraction tables
    3. Code Cleanup


  1. Announcements
  2. Action Items
  3. Commissioning Efforts
    1. Effective Velocities and Time Offsets (George)
    2. Time-walk corrections (Noemi)
    3. Layer efficiencies (Ahmed)
    4. Log Entry 3348881 First look at muon decays (Elton)
  4. Reconstruction
    1. Single-energy hits (Will M.)
    2. eta reconstruction (Tegan)
  5. Simulations
    1. CPPsim (Tegan)
  6. Any other business


Attendees: Elton, Simon (JLab), George (Athens), Mike, Will M. (CMU), Ahmed, Zisis (Regina)

  1. Announcements: Tegan, Noemi and Andrei are on holidays.
  2. Action Items
    1. F250: Mark will do this. Peak value is not in higher level objects.
    2. E vs Egen: Tegan will do when he comes back.
    3. Sampling fractions: Andrei & Tegan will look at this when they are back.
    4. Up/down ratios. Mark has updated the code so it is general purpose and user friendly. No gain ratios yet though.
  3. Commissioning Efforts
    1. Effective Velocities and Time Offsets (George): nothing new to report. Wait for next week. Report has new stuff on time offsets. The effective velocity constants will be placed into George's code first then run it and if ok upload it.
    2. Time-walk corrections (Noemi): nothing to report.
    3. Layer efficiencies (Ahmed): Weird run 1852. Elton had looked at 2931, 3079, 3179, 3182 nothing weird there. Slide 8 is for mod 7. Mike said the emulation mode for mod 8 which has an effective threshold on the data. The integral will not be emulated unless peak is more than 20 counts over pedestal. Code is in JeventSourceEvio in DAQ library. Unique difference between emulation and how we do things in FPGA. We want a uniform approach to this. David, Mark, Mike, Kei are looking at it so David will organize this. It is not a trivial solution. NSA and NSB settings are not available at that level, so this needs to be reworked for a more general solution. Slide 8: single ended hits are not included into the regular efficiency; is there a single ended hit for this events (look for such single ended hits in a printout). Elton: The event viewer did not used to show single ended hits; their is a special BCAL display that shows these. David says that it shows hits not points. Elton: we want to distinguish: a) is the E so low that one does not expect a double ended point or b) there is enough energy but we miss it. Ahmed is running a 1 MeV cut on the mod 7 runs to see if they look more than mod 8. Slide 10: not from target: maybe a vertex cut will help; puzzle why this event failed efficiency. Elton: if emulation gets reworked, then look at efficiency: preference is to reduce mod 8 threshold down to mod 7.
    4. Log Entry 3348881 First look at muon decays (Elton): ADC window set to 511 counts. First plot, bottom row-2nd plot from right, double peak: first peak muon and second is electron. Sometimes only electron peak is visible. Opposite end of the cell shows the same, verifying that it is a legitimate event. hdview shows muon stopping at 8 o' clock. Analyzed raw data (emulation might have prevented some events from being found in mod 7 mod 8). Used TSpectrum to find peaks: it gives many peaks or few peaks, but not just two; used selection cuts to eliminate bad peaks. Pulse shape was fit and fitted pulse shape was used to extract the times. Two groupings in time (muon, electron), and decay time was 2.1 us. Code is very slow: 5 Hz; it should be sped up if we want to use this for calibration (could be done in two steps). Take mod 7 data so that we can see multiple peaks. Mike: Emulation for mod 7 will not look for 2nd peak until first one is below threshold. Curtis: You want them separated by more than the pulse to get a reasonable energy sum. 3-4% of events have a valid decay.
  4. Reconstruction
    1. Single-energy hits (Will M.): this is wrapped up. His code works and will check it in early next week. Single energy hits are added into energy, but they are not used in the show position calculation.
    2. eta reconstruction (Tegan): no report
  5. Simulations
    1. CPPsim (Tegan): no report.
  6. Any other business: Simon checked in a change for the track matching of the BCAL which looks at all the hits. This helps; a reduction in the number of fake photons. (see his email).