[BTeam] [EXTERNAL] Follow up on Hall B Halo Rates Troubleshooting

[Brian Freeman]

Thank you for all the reply and the good information, these things will help.

-Brian
________________________________
From: mhattawy at odu.edu <mohammad.hattawy at gmail.com>
Sent: Friday, August 28, 2020 9:57 AM
To: Sebastian Kuhn <kuhn at jlab.org>; Bob Miller <rmiller at jlab.org>; David Hamlette <hamlette at jlab.org>; Eugene Pasyuk <pasyuk at jlab.org>
Cc: Brian Freeman <bfreeman at jlab.org>; Michael Tiefenback <tiefen at jlab.org>; Dennis Turner <dturner at jlab.org>; HyeKyoung Park <hkpark at jlab.org>; bteam at jlab.org <bteam at jlab.org>; Stepan Stepanyan <stepanya at jlab.org>; Paul Vasilauskis <vasilaus at jlab.org>
Subject: Re: [BTeam] [EXTERNAL] Follow up on Hall B Halo Rates Troubleshooting

Hello all,
  David Hamlette surveyed the upstream beam pipe, around 9 AM, and did not find any hot spot. The beam has gone at 5:00 AM, so maybe the 4 hours down time did kill all the activation. Bob Miller is in the Hall to cycle the other valve, VBF2H01A, and check the beamline components once more for any displacement.

Mohammad.

On Fri, Aug 28, 2020 at 9:28 AM Sebastian Kuhn <kuhn at jlab.org<mailto:kuhn at jlab.org>> wrote:
Just a small addition: We have already tried re-centering the beam on the target structure - TWICE - and also changing the angle with which it comes into the Hall. Nothing changed the background, and we could not find any obstructions other than the known target walls, which we avoid by centering the beam.

- Sebastian

On Aug 28, 2020, at 6:01 AM, Brian Freeman <bfreeman at jlab.org<mailto:bfreeman at jlab.org>> wrote:


  1.  We could simply try angle and position changes into the target ? It looks like things got really noisy after a target change in the hall on the 15th, probably a coincidence (https://logbooks.jlab.org/entry/3835820) . I believe that the Midstream counters sit around the Target somewhere, and Downstream counters are after CLAS. So perhaps we just have a bad angle going into the Target? ( 1hr )



--
Best regards,
Mohammad Hattawy.
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