Nov 1, 2018 Calorimeter
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Meeting Time: 11:00 a.m.
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Contents
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
- FCAL: Cross check MC changes by Richard to make sure that gains are not affected in both Geant3 and Geant4 (Matt/IHEP)
- Fix FCAL online monitoring plugin to properly plot low level digi quantities in 2D displays. 2D display of pedestal is hard to get because occupancy plot is filled in a different loop. (Tolga)
Complete after new launch
- From Mike's work: -cos(phi) type dependence in the data and a phi dependence at the downstream end of the bcal. See Sep 21, 2017 Calorimeter Meeting.
Goals for Calorimetry Group
- Determine preliminary photon reconstruction efficiencies as a function of E, phi and theta in data and simulation with a point-to-point precision of at least 5%.
- Measure systematics of pi0/eta mass calibration as a function of detector position to a precision of at east 5 MeV.
- Demonstrate agreement of photon reconstruction efficiency and resolution between data and simulation as a function of E, phi and theta to within 5%.
References
- FCAL HDFCAL log book
- BCAL HDBCAL log book
Tentative Agenda
- Announcements
- Action Items
- Run Updates
- FCAL
- BCAL
- Calibrations
- Reconstruction and Simulation
- NIM articles
- Any other business
Minutes
Attending: Elton (JLab); Will (CMU); Christina, George (Athens); Ahmed, Tegan (UofR); Rupesh, Tolga (FIU); Sean (FSU).
- Announcements
- Action Items
- FCAL online monitoring plugin. Tolga has found the code for the plugin but was unable to upload a root monitoring file and has issues editing the code. [Elton and Matt continued the bluejeans session of the meeting to give guidance.
- Run Updates
- FCAL
- Colin has adjusted the HV on inner blocks based on LED pulses on the scope. See Log Entry 3614803. Subsequent check on pi0 "peak" in data near the beam hole did not show significant improvement. Therefore a more serious effort to investigate noise/clusterizer near the beam hole will be needed in order to use this region of the FCAL effectively.
- Since the last Cal meeting, Matt, Elton, Colin met with Eugene, Fernando and Paul Smith to discuss both the short term and long term issues related to the maintenance of FCAL bases
- Near term: High current draw of some bases has raised concern because the failure mechanism is not understood and the aggregate current could possibly blow some fuses in the power supply. This will be investigated with Paul's help.
- Longer term repair: We discussed possibly fabricating more MULT boards in order to replace them systematically before they fail. There is a concern that another fabrication run may run into similar problems as the first production. For now the plan is to continue reworking existing boards.
- Collin reported at an internal IU meeting on Tuesday that a fraction of the "failed" bases removed for repair could be recovered by resetting the base. [This failure mode was known early on but was not the dominant source of failures. Resetting of the "failed" bases was not incorporated into standard practice, but now will be checked on all problematic bases before removal.]
- BCAL
- Upstream LED triggers and downstream LED triggers are set to trigger at 10 Hz, but consistently the number of upstream triggers is consistent with the 10 Hz rate, but the number of downstream LED triggers is about 5 times smaller. See https://logbooks.jlab.org/entry/3618565 Log Entry 3618565]. It has also been found that the two LED triggers seem to trigger at the correct 10 Hz rate while taking data in long mode (mode 10) vs production triggers (mode 9).
- It is suspected that the reason is that downstream LED triggers are being tagged as physics triggers. At the RC meeting it was agreed that this could be investigated without beam and we will coordinate with Sasha to check the timing of the triggers.
- FCAL
- Calibrations
- Tegan reported that Karthik Suresh (new Regina student) is working on the new gain calibrations including the SiPM saturation. So far 4-5 iterations have been made. Some changes to the mean after the first iteration, but little since.
- Will: The nonlinear correction is expected to be the most affected.
- Tegan will work with Karthik to check that 1) the SiPM saturation code is being used, 2) check stability with the code 3) check/update the nonlinear correction. With these checks, we can be ready to merge the SiPM saturation branch into the master.
- Reconstruction and Simulation
- Sean: Any updates on BCAL efficiencies? Elton: Jon will complete his study of efficiency using omegas. Beijiang is looking at the uniformity of theta in the lab as a measure of efficiency and will report back to this group on this effort. It is unclear that full coverage of the BCAL can be achieved with these processes. It might be important to understand the kinematic coverage for production of processes such as eta' -> pi+pi-eta, eta-> gg.
- Monitoring
- Ahmed. Took some LED data yesterday while the beam was down but has not yet had a change to take a look at it.
- Elton: Check for LED trigger (i.e. events with large number of BCAL hits) leakage into physics triggers and compare mode 9 and mode 10 runs.
- NIM articles
- Any other business
