BCAL Reconstruction Meeting 2015-08-06

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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. Make some plots that clarify the need for implementation of "shower curvature" information into the reconstruction.
  2. Determine up/down gain ratios for spring data (Mark)
  3. High priority items
    1. BCAL and FCAL z coordinates: some are referenced to the center of the target, not the global coordinate system.
  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)[2]
    3. Layer efficiencies (Ahmed) [3]
    4. DigiHits wrap up (Tegan)
  4. Reconstruction
    1. Update (Will M.) [4]
  5. Simulations
  6. Any other business


Attendees: Elton, Simon, David, Mark (JLab), Will M, Mike (CMU), Noemi, Ahmed, Tegan, Zisis (Regina)

  1. Announcements: LED data was taken for both North and South sections of BCAL. One LED appears to be dead.
  2. Action Items:
    1. Shower curvature plots: Tegan will re-send his email from July 13 showing the effect of implementing the shower curvature.
    2. Up/down gain ratios: This is related to gain calibration (2 step process: get mean gains and separate the two ends to use timing). U/D ratio is from the fall running. Mark will update the procedure to make it more efficient and easy to use.
    3. BCAL/FCAL coordinates: a) David and George worked on the radial coordinates. As far as z-coord is concerned, Matt had proposed to leave things as they are, since most folks work with higher level objects and do not need to worry about different coordinate systems at the lower levels. The issue originated with nonlinearity corrections for the FCAL but now the FCAL showers work ok. Anyhow, the code is well documented where coordinate systems other than the global one are used.
    4. Sampling fraction: before proceeding on this, we should review production MC plots and look at E vs Egen and extract resolution, etc. Tegan & Zisis will look at these and circulate.
  3. Commissioning Efforts
    1. Effective Velocities and Time Offsets (George): George is on holidays. He is working on corrections to his report which will be uploaded to DocDB soon.
    2. Time-walk corrections (Noemi)[5]: Noemi implemented Mike's plugin with no difficulty. (Thanks Mike). She will next look at the "goodness of correction", examine regions where the formula (see eq. 6 in GlueX-doc-2618) does not work (seek additional parametrization), vary the threshold from 14 ADC counts to other values, and looking at an iterative correction (one end ADC, other end ADC, etc. Mike will add a table into CCDB containing the 5 relevant t-w correction parameters (see Table 1 in doc 2618). Elton explained the procedure in using a0jk to use a 'typical pulse' reference point so that corrections are with respect to this physical value rather than using the value at infinity. This parameter may turn out to be the same for all channels, however, since the gains vary by a factor of 2 this needs to be evaluated. It was decided to leave it in the CCDB table anyway. Mark noted that the c0 parameter may vary from run to run; it is subtracted so this is why it is not in Table 1.
    3. Layer efficiencies (Ahmed) [6]: Ahmed showed plots for the layer efficiency, enhanced efficiency and modified efficiency (e.g., =1.2.3/2 tighter layer 'coincidence'). The modified efficiency is pretty much the same as the normal efficiency. Ahmed will focus on why layer 1 gives different efficiencies for mod7 vs mod8 and will replete his efficiency data separately for each layer as a function of run number.
    4. DigiHits wrap up (Tegan): The 'Digi" effort is compete and the code is checked in.
  4. Reconstruction
    1. Tegan is working on eta reconstruction using DReaction class vs the DEventProcessor that Will was using.
    2. Update (Will M.) [7]: The red points have single-energy hits added. Negative energy is discarded (not used in calculating points but are picked up later in the single-energy recovery). Black points may have negative energy hist in them; these may arise from too much pedestal subtracted (time integration window issue). Will stated that there can be hits that are really late but also really early. The latter might fail other criteria. The hits in clusters follow a &Delta t; = +/-8ns window. We should evaluate this to ensure that it is not too tight or to loose (Goldilocks!). Will continues on the single-energy hits studies.
  5. Simulations
    1. Tegan and David are working on the CPPsim software (using GDMP input); the BCAL hits will be entered. The volume 'copy' no (related to module, sector, layer) can be found from the given phi and r values from DBCALGeometry.
  6. Any other business