[Hallc_running] RC Daily Update 8/31

[Abhyuday Sharda]

Yesterday during DAY we were able to switch polarity in the SHMS to get ready for the positron running (https://logbooks.jlab.org/entry/4453858). Around 10pm, while changing momentum in the SHMS to -4.704 GeV to go to the last positron setting (setting 9 on pg 72- LH2 at z=0.9, π-), the SHMS Q3 interlocked (https://logbooks.jlab.org/entry/4454028). The magnet expert on call (Joe Beaufait) and Ellen had to be called to go to into Hall C to fix this. Hall C was put into controlled access and the experts were accompanied by an Assigned Radiation Monitor (ARM). Also the SHMS drive controller faulted when SHMS was being rotated. Luckily this happened before Joe went down into the Hall so he was able to reset the breakers. Joe was able to fix the fault and his log entry can be found here- https://logbooks.jlab.org/entry/4454073.

Peter took advantage of the downtime to do the configuration changes for the Heep scans. The tentative plan is to come back to the positron setting if we have time. After the drive controllers were reset, Ellen called us from the Hall and we rotated the HMS to 26.395° (https://logbooks.jlab.org/entry/4454071) while the experts were down there, set the SHMS Q3 magnet to target current (after cycling to MOL) and started the elastic runs. Ellen was able to fix the GUI so that it matches the angle camera for now (https://logbooks.jlab.org/entry/4454072). The elastic runs were completed around ~6:15 am thanks to great beam availability from the MCC (~92% during this day!). Momentum and angle changes for both HMS & SHMS were done (https://logbooks.jlab.org/entry/4454248) to collect additional statistics on z=0.50, θπγ=2.0° for LH2 & LD2. 

Updates from the accelerator-
We are all set for the energy measurement tomorrow. The MCC would wait for our cue when we're ready but we should aim to do this during the DAY shift since that's when the expert will be at the MCC who has experience with this procedure. The estimated time for this will be ~4 hours.

Shift Summaries
8/30 DAY- https://logbooks.jlab.org/entry/4453687
8/30 SWING- https://logbooks.jlab.org/entry/4453893
8/31 OWL- https://logbooks.jlab.org/entry/4454069

We will have our regular RC meeting remotely today at 2:30 pm-
Zoom link: https://jlab-org.zoomgov.com/j/1618227115?pwd=8JkhFg6YNesVc3HNgWjwUSIKIu5SvP.1
Meeting ID: 161 822 7115
Passcode: 253463
Dial-in: 833 568 8864

Sincerely,
Abhyuday Sharda

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