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</style><article id="node-715142" class="node node-logentry contextual-links-region article ia-n clearfix" role="article"><header class="node-header"><h1 class="node-title">
<a href="https://logbooks.jlab.org/entry/3642234" rel="bookmark">Follow-up Re: Hall B Cooldown to 4K</a>
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Lognumber <a href="https://logbooks.jlab.org/entry/3642234" class="lognumber" data-lognumber="3642234">3642234</a>. Submitted by <a href="https://logbooks.jlab.org/user/kashy">kashy</a> on <time datetime="2019-01-10T15:30:25-0500" pubdate="pubdate"><a href="https://logbooks.jlab.org/entries?start_date=1547148625&end_date=1547155825&book=HBLOG&book=HBSOLENOID&book=HBTORUS&book=CLOG">Thu, 01/10/2019 - 15:30</a></time>. </p>
<p class="last-update">
Last updated on <time datetime="2019-01-10T15:31:31-0500" pubdate="pubdate">Thu, 01/10/2019 - 15:31</time></p>
<table class="field-vitals"><tr><th>Logbooks: </th><td><a href="https://logbooks.jlab.org/book/hblog">HBLOG</a> <a href="https://logbooks.jlab.org/book/hbsolenoid">HBSOLENOID</a> <a href="https://logbooks.jlab.org/book/hbtorus">HBTORUS</a> <a href="https://logbooks.jlab.org/book/clog">CLOG</a></td></tr><tr><th>References: </th><td><a href="https://logbooks.jlab.org/entry/3642138">3642138 - Hall B Cooldown to 4K</a></td></tr></table></div>
<div class="logentry node-content">
<p>We started flowing to the Hall at 2g/s at 10:20 first to the Torus and then the Solenoid. We had a significant oscillation that we also had on previous cooldowns. It effected nearly every signal. This time we documented in our procedure and also here. The oscillation was stopped when we throttled PV8522TR to 10%. We believe that flow into and out of the 4K return line was heating the supply flow and causing the oscillation.</p>
<p>See plots</p>
<p>Now we are cooling the Toru at 2.8K/hr and the solenoid at 2.2K/hr.<br />
The Torus is at 73K and Solenoid is at 49K</p>
<p>The Buffer Dewar is not flowing yet and still has 21% helium level.</p>
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