RC Meeting and Run Plan, Wednesday, February 19th 2020
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Contents
RC Meeting Information
RC Daily Meetings are at 4:15 PM, 2nd floor Counting House Meeting Room
Wednesday 19th Feb. 2020.
General updates
- Orbit lock problems are still with us
- Finally got beam again yesterday just after lunchtime. Lost 4 hours the 1st half of owl today due to switchyard dump ion chamber trips. Then this morning we did a Moller measurement until 12:30 or so. We returned to production after the Moller and things have been running relatively smoothly since then.
- Back to production running with longitudinal spin direction, good polarization!!!
- Moller measurement this morning was 84.5%. Lower than before.
Pending problems
- Offline task of reference cell pressure calibration needs to get done
- The Wien flip earlier this week took a whopping 24 hours of beamtime if one includes the associated injector tuning, injector matching, and spin dances. So we hope it will not have to be flipped again- certainly not on our account.
- Try to increase ramp rate to 0.75 uA/s instead of the 0.5 uA/s we have now.
- Orbit locks: Get the position locks on reliably!!!!!
- Orbit locks have been off for long periods of time when they should always be on.
- We would like the position locks to turn on earlier, like at 10 uA.
- Display orbit lock ststus on live display screen.
- Fluctuating beam positions: https://logbooks.jlab.org/entry/3785492. Orbit locks are suspended until a certain current value is reached (very big values indeed!). A deal can be made with MCC about this.
- Ion chamber trip thresholds manipulation by MCC: https://logbooks.jlab.org/entry/3785352 https://logbooks.jlab.org/entry/3783965 https://logbooks.jlab.org/entry/3784607
- Raster energy alarm, possible cause: it's initialized for 10.43 GeV not 10.383 GeV. Ask MCC to initialize with the correct beam energy?
Not sure if it is a problem
- HMS Dipole interlock during Saturday owl shift: it's not known if a specific problem on dipole triggered the interlock but reset was successful. Happened again this morning.
- TO of the Monday owl shift reported an issue with the field correction coil readback which has been causing alarms: https://logbooks.jlab.org/entry/3785664 https://logbooks.jlab.org/entry/3786238
- Large drops and increases in SHMS Q1 LN2 levels since February 14th: https://logbooks.jlab.org/entry/3785541. Seems to be better https://logbooks.jlab.org/entry/3786755
Fixed problems
- Low longitudinal polarization seems to be fixed!
Opportunistic Problems to get done at some point
- E calibration (day shift)
- BCM calibration (to 40 uA, target out, day shift)
- Note there will need to be a recesiation of the photocathode in 10-14 d which could take 10-12 h, according to what Joe Grames said at today's 1:30 meeting.
- The injector group may just move the spot- it remains to be seen.
- This could be checked when we go down for 2-3 h in the next few days to fix a PSS problem with the lasers in the injector
Opportunistic Access Jobs
- Walter would like to pump out some of the insulating vacuum lines (needs ~4-5 h)
- Steve L./Mike F. would like to look at a sticky JT
Recent polarization measurements
- longitudinal polarization measurements after yesterday's target work in the hall and QWP angle optimization
- Tue 13:15: 47% https://logbooks.jlab.org/entry/3786686
- Tue 18:42: 52.2% https://logbooks.jlab.org/entry/3786898
- Tue 23:47: 54.5% https://logbooks.jlab.org/entry/3787175
- Wed 4:38: 55.0% https://logbooks.jlab.org/entry/3787175
- Wed 8:40: 54.9% https://logbooks.jlab.org/entry/3787285
- Wed 13:08 54.8% https://logbooks.jlab.org/entry/3787420
- Wed 18:15 54.8% https://logbooks.jlab.org/entry/3787605
Current Run Plan
- Taking production data with 3He. Stay in longitudinal until further notice. NMR every 5 hrs.
- Next Moller measurement next week sometime.
- If beam goes away for more than 2h, or if during the downtime, MCC does operations that may change then beam tuning (except work on transport magnets), then do beam recovery procedure (do YAG viewer part only if you are suspicious of the harp scan results)
- Check the position locks are on.
- Check CODA is running normally.
- CHeck 50k & full replays.
- Make sure all the beam specs are followed (e.g. no raster size below 4mm on 3He cell).
- Always take 120Hz of EDTM
- 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 !! !! !! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Future
- The transition to d2n will probably happen sometime the week of March 9-13.
- For the time being we will run exclusively with longitudinal polarization. General idea: if target polarization is about equal for transverse vs. longitudinal, alternate 4 hours of transverse and 20 hours of longitudinal data taking. Do NMR before and after transverse, and every 5 hours during longitudinal.
- Production at 30 degrees. We may want to start from HMS/SHMS=-2.9/-2.6 momentum setting, complete this and then (maybe) eventually go back to HMS/SHMS=-3.5/-3.4 momentum.
When there is a down:
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
- Spectrometer GUI (
go_magnets) should always be visible on Shift Leader computer, hcdesk3 - HMS Q1 must be ramped down in 50A steps in all cases
- Do not ramp HMS Q2 to zero, only go to 10A and then switch off power.
- If SHMS dipole trips again, take a screenshot of the PSU window before resetting the interlock and post it to hclog.
- Spectrometer GUI (
- Inform the RC of any access that the Target Team requires. The RC will coordinate with RadCon to make everything run smoothly.
- The operators have been somewhat careful with our beam orbit locks. Please make sure that the orbit locks are enabled and the beam does not drift from its nominal position.
- Ramp rate lock instructions are here and added to checklist[1]
- Temporary Laser instructions can be found here [2]
- Do not change SHMS momentum until we fixed the current lead valve
Planned Accelerator Configuration Changes
- Note there will likely be a recesiation of the photocathode in 10-14 d which could take 10-12 h, according to what Joe Grames reported at the 2/19 1:30 meeting.
- The injector group may just move the spot- it remains to be seen.
- This could be checked when we go down for 2-3 h in the next few days to fix a PSS problem with the lasers in the injector
- Bluejeans remote connection information:
To join the Meeting: https://bluejeans.com/861439920 To join via Room System: Video Conferencing System: bjn.vc -or-199.48.152.152 Meeting ID : 861439920 To join via phone : 1) Dial: +1.408.740.7256 (US (San Jose)) +1.888.240.2560 (US Toll Free)) +1.408.317.9253 (US (Primary, San Jose)) (see all numbers - http://bluejeans.com/numbers) 2) Enter Conference ID : 861439920
