Apr 6, 2017 Calorimeter
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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.
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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
-
Determine number of saturation/underflows that exist in the two LED bias monitoring settings (Ahmed)Working on periods with only one bias -
Understand the nature of the peak in the (Fcal propagated to target -RF) satellite peak of -2 ns (Adesh)Under investigation. Will use LED data to investigate this and 4 ns shift in fADCs - Disable red LED string in dark room to avoid leaving it on in the future. (Adesh)
-
Quantify the LED pulser sector jumps within one run (Ahmed)Investigation of outliers continues under study.
References
- FCAL HDFCAL log book
- BCAL HDBCAL log book
Tentative Agenda
- Announcements
- Collaboration Meeting May 15-17, 2017
- Action Items
- Most items are under study.
- Activities during the down
- Adesh will talk to Fernando/Chris/Nick about disabling red light option in Fcal dark room.
- FCAL update (Adesh)
- Pi0 gain calibrations have been completed for spring 2017
- CCDB has been updated with new calibration constants
- See a rate dependence to the gain calibration. The periods with low intensity show a pi0 peak at 130 MeV after calibration. Pedestals for these periods are fine. Will investigate with LED data.
- Non-linearity correction has been determined. A single curve function will do. (2016 data seemed to require a linear and curve function.
- Timing
- Satellite peaks at 2 ns are not understood.
- One also sees a time slewing, but the source is unclear. The slewing seems more pronounced when one uses pi0 calibration showers.
- 4ns shifts in fADC channels have not been established. The plan is to look at LED data. Ahmed: any time shifts are at the percent level, but Sean noted that other systems see a wider issue.
- Pi0 gain calibrations have been completed for spring 2017
- BCAL update
- Calibrations
- ADC timing: 4 ns run-to-run shifts in certain BCAL channels (Mark)
- Extracted 4 ns shifts channel by channel as a function of run number. This is done by comparing ADC and TDC data.
- Some channels actually see shifts in both directions (i.e. 3 peaks)
- The 4 ns shifts affect the extraction of higher level constants, i.e. gain ratio and attenuation lengths.
- Expects to commit code and tables for the 4 ns shifts later today
- The present method does not work for layer 4 because there are no TDCs on layer 4. Need to develop another procedure for layer 4.
- BCAL gain drifts: Spring 2017 all runs (Mark)
- Plot ln(ADC_up/ADC_down) vs z to extract gain ratio and attenuation lengths.
- These constants have been determined before the 4 ns shifts, but they are affected by the timing shits, so need to be redone after the 4 ns shifts are corrected.
- Gain ratios are seen to vary as a function of run number for some channels.
- Stability of LED signal vs rum number for problematic channels (Ahmed)
- Ahmed has confirmed that channels identified by Mark have poor stability. The stability is a problem for one side, usually the channel with lowest gain
- It has not been decided how to handle these problematic channels. So far about a dozen have been identified.
- Will also finds that the problematic channels are showing poor calibrations, which is not surprising since their gain is time dependent.
- Zisis: Could this be due to the summing circuit? Mark: No clear systematics has been found yet.
- Andrei: Do the channels show the same behavior at lower bias? Elton: we have been running at Vover=1.4 for over a year and have not investigated long term stability at other settings.
- BCAL gain calib (Will M.)
- ADC timing: 4 ns run-to-run shifts in certain BCAL channels (Mark)
- Reconstruction and Simulation
- NIM articles
- Any other business
Minutes
Attendees: Elton, Adesh, Mark (JLab); Sean (NW); Will (CMU); Andrei, Zisis, Ahmed (UofR); Matt (IU); Christina (Athens)
- Announcements
- Collaboration Meeting May 15-17, 2017
- Action Items
- Activities during the down
- FCAL update
- BCAL update
- Calibrations
- Reconstruction and Simulation
- NIM articles
- Any other business