[Hallc_running] [New Logentry] RC Update - July 23, 2025

[kinney at jlab.org]

Logentry Text:
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Data taking continued smoothly in the swing and owl shifts. The z=-0.67 pi- SIDIS setting was completed late in the swing and we have now started the z=0.50 setting. The O2 levels in the beam dump (which have been rising slowly over the past week) reached the level at 3am at which MCC called and limited our beam requests to less than 40 muA. Since the LD2 running only uses 15 muA, we started the second LD2 cycle instead of continuing with the solid targets. The beam dump N2 flow into the dump is expected to be fixed during the beam studies downtime, but it will take time for the O2 to fall, so we may still be current limited when we restart this evening.

A beam energy measurement was performed 7/22; see the log entry https://logbooks.jlab.org/entry/4424283. Before returning to production we asked for a harp scan (https://logbooks.jlab.org/entry/4424309), at which time it was discovered that one of the harps wasn't working; it will be looked at today during the downtime. We took a short low current run to allow Mark Jones to look into the SHMS chamber times and tracking.

Today during the beam studies, Bill Henry will fix some cable/reflections issues and Ellen will troubleshoot the HMS NMR (as well as power cycle the failed camera looking at the SHMS). Several safety training walkthroughs are also planned.

After the beam is restored, we plan to continue the z=0.5 point; since the normal target order is disrupted by the low current limit, we'll need to be careful to go back and take the skipped targets. We also plan to take DIS runs soon after the beam is restored (note these use low current!).

Offline analysis has been keeping up with the data taking, allowing us to keep track of statistics accumulated for each target. Thanks to all involved!

We will have an RC meeting today at 2:30pm. Zoom link is below.

https://jlab-org.zoomgov.com/j/1618227115?pwd=8JkhFg6YNesVc3HNgWjwUSIKIu...
Meeting ID: 161 822 7115
Passcode: 253463

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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/4424983
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