June 22, 2022

RC Meeting Information

RC Daily Meetings are at 11:00 (am) via Zoom and in person in the counting house meeting room (2nd floor)

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Useful Links

• Shift Signup (Read only)
  • Shift Signup
• PionLT_2022_Physics_Status
• KaonLT Logbook - Used for PionLT updates too
  • Physics analysis updates should be cross posted here
• Run Plans
• Hall-C Controls
• Hall-C Logbook
• MCC White Board

Current Status

• Accelerator status:
  • Yesterday swing shift, Ops was able to bring Hall C to ~ 81 uA for 1-2 sec. before it tripped (testing the machine)
  • Ops was able to deliver 60 uA of relatively stable beam during second half of swing shift
  • during Owl shift, due to beam instability, current was reduced to 45 uA
  • Ops will take beam away at 6:30 am tomorrow for full maintenance day.

• Experiment status:
  • pionLT continues to make progress on run plan, though we are still behind schedule, unless Ops is able to deliver 80 uA at >50% efficiency after full maintenance tomorrow.
  • started new setting @ 9:50 am today: LH2 SHMS Left: Q2=3.85 W=2.62 x=0.39 θ_SHMS=16.28 deg

Current Run Plan

pionLT Summer 2022 Run Plan
Physics Status

Notices in Effect for Shift Crew

• Please pro-rate ABU for max current limit in run plan (uA) in beam time accounting. For example, if we receive 15 uA instead of the max_current_limit in the run plan, then the ABU should be: ABU_prorated = 15/(max current limit) * ABU
• Check the HMS/SHMS rates for when production starts, since for Heep coin. production SHMS saw higher rates. Make sure shift crew takes snapshot of scalers at every setting
• When analyzing LD2 or Al dummy or LH2, please leave the target_mass_amu in the standard.kinematics as that of the proton, but when analyzing the data with the pionLT script, specify the target used, as different targets will have different ranges in the cuts when integrating the missing mass peak. Refer to log entry: https://logbooks.jlab.org/entry/4005387 These instructions are given in the pionLT run plan.

Current Issues

• shift crew continues to see HMS DC noise outbursts more frequently, see log-entries:
  • See log-entries: https://logbooks.jlab.org/entry/4005325 , https://logbooks.jlab.org/entry/4005330
  • study noise dependence on HMS DC thresholds, and found that noise temporarily went away @ DC threshold 5.8 V, but re-appeared on the next runs see log-entry --> https://logbooks.jlab.org/entry/4005624 This issue will have to be addressed during next Hall C access during accelerator maintenance day on Thursday Jun 23
• Hall C BCMs and Accelerator BCMc (i.e., MPS BCMs) mismatch --> https://logbooks.jlab.org/entry/4005801
  • I would think this is just a scale factor missing between the two measurements? Usually S. Wood did this in the past. I have notified S. Wood in the log-entry

Planned Accesses to the Hall

• During the accelerator full maintenance day (Thursday Jun 23, 2022)
  • S. Lassiter needs to put crush washers in LCW filters, so we may see a little bit of water by the HMS boogie for now, until he can put the washers next week, during maintenance period HMS Dipole LCW ( PENDING ) NOTE: Actually, Heidi and Jack will will need to access Hall C to work on HMS dipole, to get dimensions before ordering the parts needed to install the crush washers.
  • Hall C drift-chamber expert will need to go to the HMS Hut to try and fix the HMS DC noise issues. Maybe better grounding is required? Or discriminator cards may need to be re-seated? ( PENDING ) See HMS DC Card Map: https://hallcweb.jlab.org/wiki/images/1/11/HMS_DriftChamberPlanesLayout.pdf and log-entry: https://logbooks.jlab.org/entry/4005562 describing which wire groups are noisy
  • Xinzhan Bai and Jixie Zhang request to change gas bottle for solid Cherenkov detector: Contact: xbai@jlab.org, cell: (434) 422-2809 ( PENDING )

Planned Accelerator Configuration Changes

• Full accelerator maintenance day on Thursday, Jun 23. Beam will be taken away at 6:30 am

Special Requests

• Mark Jones would like to take HMS optics data with a 4x4 mm^2 raster at some point (when HMS is at a lower momentum, i.e., current setting) for checks. ( DONE )
  • D. Gaskell took a run with Carbon target and raster set to 4x4 mm^2. See run https://logbooks.jlab.org/entry/4004280