[Hallc_running] [New Logentry] RC Update - July 18, 2025

[kinney at jlab.org]

Logentry Text:
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Day shift 7/17 was a maintenance day; the SHMS was moved to 7.87 deg under the watchful eyes of the crew. Ellen tried to repair the HMS NMR system, but the same issue with the multiplexor board existed using the board from Hall A (signals from all probes at the same time). Ellen is now troubleshooting and we hope to have a repair in the next few days; there is no spare. Our present kinematics does not required changing the HMS field for several days, so the plan is to leave it set by current until we can check the field with a repaired NMR.

Beam was restored just before midnight and we started collecting pi- SIDIS data at x=0.25, Q2=3.3, z=0.36, and by 8am the initial target rate scan was completed and the first full target cycle was almost completed. Beam current was set to keep to a conservative 1 MHz in SHMS S1x which resulted in SHMS 3/4 of around 700 kHz at 15 uA on LH2. Day shift will try increasing to 20 uA and investigating whether we can take at the higher rate (S1x at 1.4MHz, SHMS 3/4 at 900 kHz).

We will continue target cycles at this kinematic. During Cycle 3 we will take DIS data from each target and using each spectrometer. Tentatively our first BCM calibration will take place Saturday 7/19 at 2pm. 

Work to understand our actual yield accurately is a major goal for today. The 50k replays seems to still be using the wrong cuts.

There will be an RC meeting today at 2:30 pm in the meeting room on the 2nd floor of the Counting House. The usual Zoom information 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/4420805
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