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</style><article id="node-475514" class="node node-logentry article ia-n clearfix" role="article"><header class="node-header"><h1 class="node-title">
<a href="https://logbooks.jlab.org/entry/3402685" rel="bookmark">RC Report for Sunday, April 24</a>
</h1>
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<p class="author-datetime">
Lognumber <a href="https://logbooks.jlab.org/entry/3402685" class="lognumber" data-lognumber="3402685">3402685</a>. Submitted by <a href="https://logbooks.jlab.org/user/vasulk">vasulk</a> on <time datetime="2016-04-24T11:36:58-0400" pubdate="pubdate">Sun, 04/24/2016 - 11:36</time>. </p>
<table class="field-vitals"><tr><th>Logbooks: </th><td><a href="https://logbooks.jlab.org/book/halog">HALOG</a></td></tr><tr><th>Entry Makers: </th><td>vasulk</td></tr></table></div>
<div class="logentry node-content">
<p>Yesterday evening, production data taking on the LH2 target was resumed after the beam was off, since about 9:30 in the morning.<br />
The issue with beam involved a vacuum valve, VBV1L24A being in an indeterminate state. The resolution is described in this<br />
ELOG entry: <a href="https://logbooks.jlab.org/entry/3402347">https://logbooks.jlab.org/entry/3402347</a></p>
<p>Unfortunately, while MCC was working on recovering from this issue, strong storms came through the area yesterday afternoon<br />
disrupting the operation of the C100s. After the storms passed, the RF stabilized and MCC continued restoration of the beam.<br />
Beam was returned to Hall A around 16:50, which then the Hall A shift crew began the beam restoration procedure. Production<br />
on the Loop 3 LH2 target resumed around 18:30, though at only 45 uA due to BLA trips when MCC attempted to run higher current<br />
to Hall A. Unfortunately, there was also large bleed through of the Hall A beam into Hall B, but apparently this magically disappeared<br />
on its own: <a href="https://logbooks.jlab.org/entry/3402458">https://logbooks.jlab.org/entry/3402458</a><br />
The resolution however did not improve the BLA trips for running Hall A at higher currents.</p>
<p>Production running continued well through the remainder of Swing into Owl shift. Then at 00:40, the raster YB power supply failed.<br />
Bill Gunning came in and replaced both the XA and YB power supplies by 02:10. See Halog: <a href="https://logbooks.jlab.org/entry/3402533">https://logbooks.jlab.org/entry/3402533</a>.<br />
The shift crew then proceeded to check the beam spot and raster size by lowering the left HRS momentum to 1 GeV/c to obtain<br />
some rate to see the carbon hole. The raster size was restored to 2.5 x 3 (MCC units) to give approximately a 2 x 2 size at the Hall A<br />
target. The beam position was found not be be centered on the carbon hole. The positions at BPMA and BMPE were adjusted from<br />
(0.3,-2.4) to (0.0,-2.6). Production at 45 uA on the LH2 target was resumed at 03:40. The shift crew asked for MCC to provide 60 uA,<br />
but the beam would trip as they went above 45 uA. Then after 06:00 the BLA trips got worse, and MCC lowered the Hall A current to<br />
40 uA, which improved the trip rate.</p>
<p>For today through tomorrow morning, we will continue production running on the LH2 target at as high of a current as MCC can delivery.<br />
I still hold out some hope that we can get back to higher currents. Around 15:30, we will take data for two hours on the 15 cm dummy<br />
target, and the continue production until 06:00 Monday, when beam goes off.</p>
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