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We should only need 1 additional channel, for the magnehelic, right? I figured we'd reuse the MFC channels for the MFM.</div>
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I have a 'new, old stock' magnehelic in my office. I say 'new' since it's been in it's box, in a drawer, for at least as long as I've been here, ~10+ years.</div>
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Before anyone orders Dwyer/MKS sensors, let me know, as I need to replace one on the DC MKSs and would like to have a spare.<br>
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-Morgan<br>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Brian Eng <beng@jlab.org><br>
<b>Sent:</b> Wednesday, February 9, 2022 11:41 AM<br>
<b>To:</b> Morgan Cook IV <mcookiv@jlab.org>; dsg-hallb_htcc@jlab.org <dsg-hallb_htcc@jlab.org><br>
<b>Subject:</b> Re: HTCC: leak and proposed modifications</font>
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I think the changes Morgan suggested make a lot of sense.</div>
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We should have available channels to read out the additional signals, but let me double check.</div>
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Was the plan to order a new MFM or will an existing one be repurposed? As for the sensors it's probably better to just order new ones, if there is a Dwyer one in the range needed they're significantly cheaper and faster to get than the MKS ones.</div>
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<div id="x_divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>From:</b> dsg-hallb_htcc <dsg-hallb_htcc-bounces@jlab.org> on behalf of Morgan Cook IV <mcookiv@jlab.org><br>
<b>Sent:</b> Wednesday, February 9, 2022 11:17 AM<br>
<b>To:</b> dsg-hallb_htcc@jlab.org <dsg-hallb_htcc@jlab.org><br>
<b>Subject:</b> [dsg-hallb_htcc] HTCC: leak and proposed modifications</font>
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Youri, <br>
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I'm not convinced that there is a leak in HTCC. The attached picture was taken yesterday, yet the MKS 223 (pressure transducer output to Epics) read 0.08 iwc. (Unfortunately I can't tell what the bubbler is doing yet, since it's wrapped in cloth.) While it's
possible that either one or both of these pressure transducers is bad but it's more likely that they just need to be re-zeroed. Either way, I'd like to see some changes made to the system.</div>
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<ol>
<li><span><span>Bring the magnehelic signal into Epics. I don't know why this wasn't done, the current one has the capability. You can have pressure alarms on either signal but it might make sense to set the alarms on the average.</span><br>
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<li><span>re-zero or replace both of the transduers with new.<br>
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<li>Remove the MFC. We don't gain anything by using it. And, for whatever reason, it is not uncommon for this one to lose power, communication, develop sentience, etc...<span> and randomly stop working. During RGM this happened twice, that I know of. We can't
and don't trust it. So, take it out of the system. Run all gas flow through the rotameter.
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</span></li><li><span>Add a MFM (mass flow meter), in series, behind the rotameter. This tells us how much gas is actually flowing to the detector and allows correlation between gas flow, chamber pressure, gas efficiency, chamber efficacy, RGA results, and a host of stuff
I haven't thought of. </span></li></ol>
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<div>-Morgan<br>
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