[Hallc_running] [New Comment] RC Update - Meeting at 10:00 Tomorrow Morning

[sjdkay at jlab.org]

Comments:
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 - by sjdkay on Sun, 09/12/2021 - 19:14.

Forgot those pesky tags again - Forgot those pesky tags again.

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Logentry Text:
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Keep an eye out for Agent Smith because there's been some deja vu over the weekend. Smooth beam through swing yesterday, then no beam at all over owl. We lost beam around midnight and didn't get it back until just about 09:00 this morning. Sound familiar?

Once we got beam back, we finished off the LH2 and Dummy target positive polarity settings at 6.26 degrees on the SHMS. We also got the BCM calibration sorted today. We just started on LD2 where we'll be sitting for 11 hours of beam. This should take us through till we lose beam for the work tomorrow (and probably a little after). 

As we've seen so far with this physics setting, rates are higher than expected. On LD2 with the SHMS at 6.26 degrees, we're seeing 960 kHz in the SHMS S1X and 400 kHz on the SHMS 3/4 trigger with 10uA of beam. Once we switch to negative polarity, those rates are only going to get worse. If we treat the negative polarity setting as the "sequel" to the positive polarity one, we can get a free bonus Matrix reference out of this too. Much like the Matrix sequel, our sequel will be noisier and less coherent too.

In terms of Hall Access, we expect to lose beam at any point after 04:00 tomorrow morning for Hall D related work. I've requested a survey from Radcon at 09:00 so we can drop to Controlled Access. If anyone needs to do something that would require a drop to Restricted, let me know and we can try to accommodate it. I would rather avoid that if possible.

A few topics on the agenda at the RC meeting beyond the usual status updates -

- The ongoing HGC mystery, potential causes and solutions
- A  game plan for the LD2 -ve polarity setting

See you all at the meeting tomorrow.

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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/3904707
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