[Hallc_running] [New Logentry] RC Daily Update

[sjjooste at jlab.org]

Logentry Text:
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Once accelerator realized they couldn’t deliver 37uA, things ran mostly stable at 35uA during swing and owl. Today during day we won’t have physics beam due to planned beam studies aimed at fixing the issues to deliver high current to Hall C. You can find the beam current history for the last 24 hours here: https://logbooks.jlab.org/entry/3609814

More info about the beam tuning operations here: https://logbooks.jlab.org/entry/3609479.

Yesterday around 7:50pm, the HMS Dipole and Q3 suddenly lost current (the dipole probable quenched, luckily we were at relatively low current). Everything was restored back to normal at 9:10pm, so we lost 80min. The shift crew noticed peaks on the warm return when the magnets lost current https://logbooks.jlab.org/entry/3609532. I learned this morning that this coincided with the moment where Hall A warmed up their target, which is most likely what caused the HMS dipole to quench.

This morning during the beam studies, the SHMS DCs started to trip around 60uA (as expected. We switched of the SHMS DC HV for now. We also masked the alarms in the alarm handler. https://logbooks.jlab.org/entry/3609751

It looks like the JT-4 valve for the HMS Dipole LN2 level is responding again today. This might have something to do with the dipole quench of yesterday night. I talked to Andy and we decided to go in for an escorted access tomorrow during the RF recovery to replace the motor to prevent this from happening in the future. Andy expects this to take about 5-10 minutes.
https://logbooks.jlab.org/entry/3609753

As of right now, we have collected 23% of the statistics goal for LH2 on Q2=5.5, W=3.02, theta_Shms=6.49 during 3 shifts.
Tonight during swing we will most likely interrupt running this setting to conduct the luminosity scan. Tentative run plan for this scan can be found here: https://hallcweb.jlab.org/wiki/index.php/Run_Plan_for_Kaon_LT_Luminosity_Scan
We will then resume taking production data on the same kinematic point for another 2-3 shifts , or until we reach 50% of the statistics goal.
Note that this time allocation excludes the time needed for todays beam studies, the luminosity scan and tomorrow’s RF recovery. 
More info about the Kaon LT status here: https://hallcweb.jlab.org/wiki/index.php/Kaon_LT_Status_Page

There will be an RC meeting today at 4:30 pm on the second floor of the counting house.

After the meeting you can find the talking points here:
https://hallcweb.jlab.org/wiki/index.php/RC_daily_meetings_and_daily_runplan_fall_2018

To join the Meeting:
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This is a plain text email for clients that cannot display HTML.  The full logentry can be found online at https://logbooks.jlab.org/entry/3609815
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