[Rgc] [New Logentry] RC Daily Summary, Oct 28th 2022.

[deurpam at jlab.org]

Logentry Text:
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RC Daily Summary, Oct 28th 2022.

Summary from Thursday-owl (10/27/2022) to Friday-Owl (10/28/2022)

General Summary:
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This was not a productive day: beam was taken away at 7:45am for RF-recovery. It was restored at 17:50, much later than the noon expectation. During that time, the hall went into control access to allow for target work: (1) NMR study to try to understand the discrepancy between target polarization estimates from NMR vs trigger helicity asymmetry; (2) changing ND3 material to Carbon. The target change went well, but no smoking gun was found that could explain the NMR/trigger hel. asymm. discrepancy.
Once the beam came back, its quality was checked with the 2C21 and tagger harps. This was followed by a Moller run that measured 85% beam polarization. Production on Carbon started around 21:30 but the beam went down at 23:00 (RF instabilities). It came back at 00:30 for a few minute but then [https://logbooks.jlab.org/entry/4071560 a burning RF power supply cable] triggered the North Linac VESDA system, which in turn trigger the NNFD to go in to investigate. After the firefighters cleared the area (1L18 in North Linac), the beam was terminated for the night, pending investigations by experts. They found that the damage was minimal and the expectation is that the beam should be back around noon today.

As a consequence of all this, today's run efficiency was low, with an ABU of 2h (7am yesterday to 7am today).

Events accumulated (~7am yesterday to ~7am today):
59 M events (runs 17296 (ND3) + 17304/17305 (12C))

Plan:
Production on carbon. Tentatively, Saturday at 4pm, we will change target from carbon to CH2, but this will depends when the beam comes back.

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We will have our regular RC meeting today at 2.00pm

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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/4071660
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