RC meeting and Run Plan, Friday December 10th

RC Meeting Information

Run Coordinator: Brian Quinn

Location: Counting House Conference Room

Time: 3:15PM

Remote connection link: https://bluejeans.com/256205934

Toll-Free Number (U.S.& Canada): 1-888-240-2560

Bluejeans Meeting ID: 256 205 934

No RC meeting this weekend... unless something comes up

Upcoming Shifts Which Need Filled

A total of 4 shifts remain until the winter break shutdown one of which is tomorrow!!!!!

1. Sat Dec 11th, DAY, SL
2. Wed Dec 15th, OWL, SL
3. Fri Dec 17th, OWL, TO
4. Sat Dec 18th, OWL, TO

Thanks!!! to Thir, Scott, Nathaniel, Maria, Bob, Sean, Kondo, Albert, and Zeke!!!

Accelerator and Hall Status

• Possible 4-hour optics studies 7 AM Tuesday.
  • Requested controlled access, if so. Decision to be made 9 AM Monday.
• 1/8" Al sheet placed outside BB vacuum window on target chamber (previous 1 cm plastic removed)
• Now running with higher currents (11 uA for LD2, 15 uA for LH2)
• Increased BB trigger threshold to 480 mV (from 470) (DT ~ 8% -> for LD2) to lower trigger rate to 2600 Hz instead of 3200 Hz. (Did increase to 480 mV on Thursday swing shift

To Be Done During Extended Down Time

• (BBCal) Would like more cosmic data at nominal HV.
• (HCal) Would like to take LED-only runs
• Removal of INFN J2 from Hall. (Jessie) Zeke would like it to be ASAP after end of December run.

Run Plan

• Finished Cycle 12 today
• Did low current (2 uA) test runs with GEM voltages decreased by 50, 25, and 0 on LD2
• Now taking LD2 data for Cycle 12
• Continue following cycle pattern and ticking off runs-completed on paper copy at SL desk
• Friday swing shift: SBS-off running. 2hr LH2, 3hr LD2 (Need to change BB Cal HV settings)

Opportunistic Access Requests (Running List)

• Put network-readable 'scope on trigger signals to quickly identify 70 ns timing shifts. (Alexandre)
• Try changing HV channel for J0 lower module (to see whether lower current is a result of bad read-back) and perhaps check HV divider (if accessible) (Zeke or Holly).
• Remove unused HV card for hodoscope (Ralph)
• GRINCH (change pulser brightness) (Todd/Maria)
• Maybe, if rate of failure increases, change rpi & SD card in HCal's upper HV mainframe (Sebastian & Ellen)

Resolved Issues

• Low DAQ rate alarm for hung MPD (End, Reset(twice?), configure, download)
• GRINCH LED pulser now prescaled (PS5=4) to give ~10 Hz
• "MPD NotFound" error:
  • See two-page printout from GEM documentation, on SL desk
  • On page 3, section 3.3 (marked by bracket in the margin) tells how to boot the VTP crate
  • If that doesn't fix it, see the next page for how to boot UVa MPD crate (or call Alexandre or GEM expert on call)

Unresolved Issues

• Hodoscope HV alarms (Ralph and Steve are working on it)
• BBCal HV alarms with CH HV-control showing HV off by more than 50 V while JavaGUI shows it at setpoint
• BBCal HV alarm with JavaGui showing HV at ~500 V
• Occasional timing shifts of ~70 ns
• GRINCH sync errors (can be ignored)

Subsystem Updates

1. HCal
1. F1 errors (HCal sync errors)... Don't ignore!! End, Reset(twice?), Configure, Download.
2. Correlation plot of HCal ADC time and HCal TDC gives clear sign of 70 ns shift in either ADC or TDC.
3. Binder of good and bad HCal plots for LH2 and LD2 target will be put in CH
2. BBCal
3. Timing Hodoscope
1. How is progress on identifying right RF pulse??? Covered at today's DAQ mtg?
4. GRINCH
1. HV has been adjusted to give ~10 ns time-over-threshold for single photoelectron
5. GEMS
1. HV was lowered 50 V for test. Efficiency stayed high, but number of tracks dropped ~25% ????
2. Kondo suggests resulting 20% drop of leakage current may increase the gain (because of less sag of last element of divider chain.
3. Kondo opposes increasing beam current to take advantage of decrease in leakage current, if we choose to run with the lower voltage.
4. Diagnosing efficiency would be easier with low current runs (~1-2 uA) on either LH2 or LD2 with low BBcal threshold to give ~3 kHz trigger rate. Done today.
5. Nilanga recommends changing GEM HV with HV turned off, to prevent typo from destroying a GEM.... or set a maximum on the HV control system. (Done for today's test.)
6. J0 top may be usable.
7. J0 bottom may have only a problem with current read-back on HV power supply channel, or problem with HV divider.
6. Beamline
1. Unser has been calibrated with precision-current source
2. BCM calibration w.r.t. Unser can be done with existing data at different beam currents.
3. Bullseye scan using BPM to set beam deflection, and harp to quantify beam deflection calibrates BPM (relative to harp). This is not of obvious use to this experiment.
4. If bullseye scan used raster magnets to move beam to corners of raster range and calibrated that w.r.t. harp, that MIGHT be of use, if the <x|x> and <x'|x> matrix elements are large enough to significantly affect extraction of p, based on precise knowledge of x-position at target, obtained from raster settings during normal operation.
5. Evaluation of sensitivity of extracted-p on x-position must be evaluated to determine whether understanding of x-position as a function of raster current significantly improves determination of p. (Bogdan predicts that raster-position can affect p-extraction at 0.5%-level.)
7. Replay analysis
1. Replayed low-current LD2.
2. J-cached optics runs of SBS-11.
3. Straight-through run of SBS-11 was used to extract GEM alignment info.
4. Will re-run optics runs using alignment info.
5. Will look for LH2 elastic events to use them to understand BBCal and HCal responses.