RC Update and Run plan for Sep 19,2020
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Saturday 19 Sept 2020.
General updates
(See d2n Run Plan 2020 for broader status/overview.)
- Beam energy measurement started at Fri 2:15pm [1], completed around Fri 5:30pm (including restoring production optics)
- Fri 5:15pm--7:45pm Ion chamber calibrations on No Target, Carbon-Optics, and Ref Cell(135psig N2):* Will continue with 1-pass runplan
- Fri 7:55pm Began 1-pass production
- Fri 11:30pm SHMS dipole tripped, not clear why.. Reset cleanly though [4]
- Run plan delivered to shift crew: 1-pass running program
- -Done- Beam Energy Measurement (1 hour)
- -Done- Reference Cell Empty, Hydrogen (H2), Carbon Cross Sections (3--4 hours)
- -Done- No Target Run
- -Done- 3He Reference Cell Runs (N2 and 3He Pressure Curves, False Asymmetries) (5hrs ideal, 3 hrs min)
- -Done- Reference Cell He3 Cross Sections (1 hour)
- -- In Progress -- Polarized 3He Runs, 3He elastic and QE longitudinal Asymmetries (16 hours)
- ~50% complete as of Sat, 2pm
- Flipped Target polarization to Longitudinal/0 around Sat, 2:30pm [5]
- Another ~8 hours of production follows
- Polarized 3He Elastic Longitudinal Asymmetry (until end of 1-pass running)
- NOTE: OPS/MCC would like to stop beam at 7am for some Accel tests
- Some beam energy stability issues have been noticed by Hall B (in particular); Jay is looking into this
- These should not impact Hall C significantly, but may feed into beam polarization corrections.
- Jay has link some of this discussion to the Hall C beam energy measurement HCLog entry and cross posted to the HCLog. This will help us follow breadcrumbs during beam polarization analysis for 1-pass.
- Hall C beam energy drifted up after the Hall C beam energy measurement was taken [6]
- Hall B Moller Fri, 09/18/2020 - 10:20 was higher than expected: -86.233 +/- 1.494 (several percent) [7]
- Energy shift that would impact Hall B polarization at few percent level [8]
- Energy lock switched from 2A to 3C Sat (19th) @ 9:40 [9]. No notice to Halls, unfortunately..
Notes for the Future
- 1-pass running program
- MCC/OPs is requesting that beam delivery to Halls be halted at 7am instead of 8am to run a couple measurements
- Measurements are intended to guide future work on beam and energy stability issues noted earlier.
- Hall will move to Controlled Access on Monday
- When is still TBD; depends when RadCon is available
- Could be in the afternoon
- EPR photodiode will be replaced on Monday (JP, Junhao, RadCon)
- Will move to Restricted Access ________ ?
- Bill, Murchhana check compass/field measurements
- Also checking with Jixie re: modeled fields
- Need to make a write-up that clearly defines all the different coordinate systems used, swapped power supply/polarity issues, etc.
- Start prepping for post-run work
- See POST-run Calibrations/Measurements for list
- HCList being prepared for submission on Sunday
Pending Issues
Opportunistic Jobs/Access
Current Run Plan
Friday SWING → Monday
- See task list at Run Plan for 1-pass for more details
- Priority will be PbPt polarization cross check with longitudinal pol. elastics.
- These have lower priority but will likely be pursued first while target spins up
- Beam energy measurement (1st thing)
- 3He, N2 density measurements
- H2 xsec measurement
- Pressure curves
- NOTE: Hall C is in control of the Charge Asymmetry feedback system until Monday
- Charge Feedback Parity DAQ Instructions
- We will have to run the
./FlipPCvaluesHallCscript in the Parity DAQ VNC session after every IHWP change
Standing Orders
- Change the IHWP at least every 8 hours when running on glass cells. Call Halls A and B in advance. If there are any issues, call the RC
- NOTE: Hall C is in control of the Charge Asymmetry feedback system until Monday Charge Feedback Parity DAQ
- We will have to run the
./FlipPCvaluesHallCscript in the Parity DAQ VNC session after every IHWP change
- Ensure that all information in the CODA run-start GUIs is correct for every run!
- If beam goes away for more than 3h, or MCC does operations on the beam that may change the beam tune, then move target to No Target position,
- verify Harps scans at 3H07A and 3H07B are within spec, and
- ensure beam is stable (with all locks ON) at 0, 0mm before continuing.
- Beam recovery procedure has more detailed procedure if needed.
- New beam positions have been verified and established to be (0,0) mm for all targets.
- Monitor that beam is at (0,0) using the stripchart on the Wall screen and verify no scraping on the glass cells using the Analysis monitor.
- Check the position locks are on.
- Check that CODA is running normally
- Check online replays shortly after starting runs, & full replay results too.
- Fill BTA with realistic numbers. You may follow the guidance coming from "load from EPICS", if it does not overestimate the ABU (as it generally does). https://logbooks.jlab.org/entry/3783171. If we have to lower the beam current we actually want because the beam is too unstable, prorate the ABUs.
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !! !! !! ATTN: SHIFT LEADERS !! !! Please follow the shift summary template on !! !! the laminated SL instructions. !! !! !! !! ATTN: TARGET OPERATORS !! !! All NMR measurement HCLOG entries should include: !! !! 1) A title that clearly lists polarization !! !! 2) Screenshots of both NMR_FieldSweep and !! !! the polarization fit !! !! !! !! For an example see the following entry: !! !! https://logbooks.jlab.org/entry/3768696 !! !! !! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Notices in Effect for Shift Crew
- Policy for CANS-related hall status change: Make a logbook entry when the hall goes in, or comes out of laser-controlled access.
- Magnet policies
- Follow the updated guidelines in the How-to#Spectrometer_Magnets Spectrometer Magnets How to
- Spectrometer GUI (
go_magnets) should always be visible on Shift Leader computer, hcdesk3 - If any magnet trips, snapshot the associated power supply window and post it to hclog before resetting the interlock.
- Monitor the beam position on target and call MCC immediately if you see large excursions (1 mm level).
- When rotating the spectrometer, use HCCAM01 to keep an eye on the SOLID Cherenkov test stand when rotating SHMS (in addition to watching the live angle-cam image, etc). The updated rotation instructions are here: https://hallcweb.jlab.org/wiki/index.php/Spectrometer_Rotation#NOTICES_IN_EFFECT
Useful Links
PolHe3 Polarization Measurements
