Sep 8, 2016 Calorimeter
From GlueXWiki
Contents
Video Conferencing Information
Meeting Time: 11:00 a.m.
- To join via a Web Browser, go to the page [1] https://bluejeans.com/907185247.
- To join via Polycom room system go to the IP Address: 199.48.152.152 (bjn.vc) and enter the meeting ID: 907185247.
- 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
- 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.
- 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
- Athens Phone: in Christina's office is 011-30-210-727-6947
Action Items
- Produce documentation for implementation of timing algorithms and constants (Andrei)
References
Tentative Agenda
- Announcements
- Action Items
- Preparation for REST production
- FCAL update
- BCAL update
- Variance-covariance matrix for BCAL showers matrix elementsexample distributions
- Timing comparison plots
- Calibrations
- Reconstruction and Simulation
- Any other business
Minutes
Attendees: Elton, Mark, Adesh, Jon (JLab); Sean (NW); Matt (IU); Curtis, Will (CMU); Zisis, Andrei, Ahmed (UofR); Christina (Athens).
- Announcements
- Solenoid has been powered at 1350 A for about a day and a half.
- Action Items
- Preparation for REST production
- Launch is now in progress
- FCAL update
- Hardware
- Turned on HV to all pmts
- FADC crates do not yet have the new firmware. Expect updated firmware by Monday so that we can start checking detectors
- At the moment there are 10 problem bases: 6 from the spring run, 2 with communication issues and 2 new problems. It appears that there has been no degradation of the bases with the HV off.
- To date we have fixed about 500 bases
- Chris Stanislav has a working setup for testing/fixing bases here at JLab. He believes he is ready and capable of fixing bases, but has not started due to other priorities.
- We currently have 100 spare bases on hand.
- Nick has repaired and replaced two fADC boards that had single failed channels. There was a connection problem at the input.
- Hovanes has made available a PDU to power the supplies and it is being installed in the hall. This will allow remote cycling of power.
- Another iteration will be made on setting the HV on the bases to adjust the gains in hardware. Once the DAQ is back running, the LED pulser system will be used as feedback for adjustment along with the gains determined using the pi0 calibration.
- Adesh expects that the adjustment will be less than 10 V. The hardware adjustment will minimized variations in individual thresholds.
- Hardware
- BCAL update
- Hardware
- BCAL voltages have been turned back on.
- Two LV channels failed over the summer and failures were traced to the MPOD electronic boards. These have been replaced. Fernando and Chris are looking into fixing the boards and will check on spare availability. Note that a single LV feeds 4 Bcal modules.
- Ahmed: Noted that the LED monitoring data during the run had periods of jumps by quadrants. Elton said that the distribution of the pulser signals is done by quadrant and this may be a connection. There remained several detailed questions that we decided to discuss offline.
- Matt: How is the pulsing going to proceed for the run? Elton: It was setup for pulsing continuously through the run for both Bcal and Fcal. The Bcal has a script that runs asynchronously with data taking and cycles through all 16 configuration. The Fcal probably wishes to setup something similar. Adesh will talk to Hovanes to see how best to implement such a scheme.
- Variance-covariance matrix for BCAL showers matrix elementsexample distributions
- Mark has been working on obtaining variances and co-variances for the BCAL from simulation. The var and covar are computed in a five dimensional space E, phi, z, r, t.
- Tables are generated using MC covering the variables of interest. The var and covar are saved as lookup tables, which can be accessed in DBcal_shower. The code has been modified to use these tables by transforming to the appropriate coordinate system.
- The alpha software is ready now and will be checked in soon. Testing is needed before use in the next software launch.
- Paul Mattione will test the tables in the kinematic fitting routines and see how it improves the resulting errors.
- Mark is starting a document to describe the work, which will be made available for comments and feedback.
- Elton: Can this system be used to produced similar tables for Fcal? Mark: Yes, if that is desired.
- Timing comparison plots
- Zisis summarized the status of Andrei's work as an introduction and reminder. The BCAL timing calibration has been completed by empirical fitting of veff for up and down separately. At the last meeting there were questions about systematics and philosophy and many will be addressed next. Documents have been collected, including a link to the calibration procedure by BELLE for their tof system, where they also fit separately for veff up and down.
- Andrei:
- Presented comparison of the hit distribution: Andrei's z, George's z (uses Andrei's TDC times and George's procedure, quadratic veff), FADC z (uses constant veff per layer)
- George's z with Andrei's time is shifted relative to the center of the calorimeter
- There was some question regarding precisely which constants Andrei was accessing. Sean clarified that the variable JANA_CALIB_CONTEXT needs to be set to pick out a specific run. Otherwise it defaults to the latest
- Christina: The width of the position determined by George has a mean closer to zero and a narrower distribution.
- Matt: Concerned that the procedure is producing systematics as a function of z
- Andrei: Notes that the procedure is optimized to minimize the time resolution and the position resolution is obtained as an aside.
- Christina: Goal is to optimize physics and "naturalness" is less important
- Matt: Naturalness may improve systematics in areas not yet studied
- Zisis: Several conflicting requirements (time and position resolution) are at play and ultimate optimization for physics still needs to be worked out.
- Andrei continued with his presentation. Next he showed the meantime resolution for single cells. Resolution fits give about 70 ps/sqrt(E) + 170 ps in layers 1 and 2.The constant term was been reduced from about 270 ps using this new procedure, which is a substantial improvement.
- Elton: Have you looked into combining times from different layers into a single time for the shower? Andrei: Yes, but for the algorithm used, the combined timing is worse than the individual layers. This is a work in progress.
- Elton: What will it take to incorporate this calibration into standard pluggins that can be run during analysis launches? Andrei: Not quite sure that is needed for that step.
- Zisis has made notes of discussion and points to dig deeper.
- Hardware
- Calibrations
- Reconstruction and Simulation
- Any other business
