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<div class="moz-cite-prefix">Hi Fernando,<br>
<br>
As we have discussed, the temperature accident happened<br>
not the first time. After the first accident, when we <br>
melted a CTP module by running a fan speed at ~2000 rpms, <br>
I took many trigger-related (and other) crates from the <br>
PID control and ran them at 4500+ rpm.<br>
<br>
After the overheating problems during last year, Hai Dong <br>
suggested to run the fan at about 5000 rpm for the sake of <br>
CTPs, and I agree with him. There should be enough margin <br>
to cool the crate down if the temperature in the hall <br>
increases.<br>
<br>
<br>
The CCAL crate, positioned on the same FCAL platform <br>
runs at about 5000 rpm for more than a year, I didn't <br>
have any problems with it so far.<br>
<br>
<br>
I belive that the PID fan threshold should be set to at <br>
least 4500 rpm for all crates (indeed it's a choice of <br>
sub-detector groups, who should be responsible for <br>
damaged electronics as well).<br>
<br>
<br>
<br>
Cheers,<br>
Sasha<br>
<br>
<br>
P.S. Indeed, there could be other not temperature-related <br>
issues, but this is the most likely one.<br>
<br>
<br>
Rad damage can be an issue as well, but then modules should <br>
fail "continuously" during the run, likely with various symptoms, <br>
which seems to be not the case. We got 5 modules dead after <br>
the run. The rad dose in the tagger hall is also significantly <br>
larger than in Hall D; I haven't seen such problems with fadcs <br>
there.<br>
<br>
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<div class="moz-cite-prefix">On 11/15/19 3:10 PM, Fernando Barbosa wrote:<br>
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<p class="MsoPlainText">Hello Elton, all,<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">Some notes regarding the paragraph below:<o:p></o:p></p>
<p class="MsoPlainText" style="margin-left:.5in;text-indent:-.25in;mso-list:l0 level1
lfo1">
<!--[if !supportLists]--><span style="mso-list:Ignore">a)<span style="font:7.0pt "Times New Roman"">
</span></span><!--[endif]-->The overheating is not an issue unless the hall temperature increases significantly above the specs. For a full description, refer to GlueX-doc-2752. My recommendation has always been to operate the fans fixed at 4,000 RPM or in
the 3,000 RPM to 5,000 RPM range under PID control.<o:p></o:p></p>
<p class="MsoPlainText" style="margin-left:.5in;text-indent:-.25in;mso-list:l0 level1
lfo1">
<!--[if !supportLists]--><span style="mso-list:Ignore">b)<span style="font:7.0pt "Times New Roman"">
</span></span><!--[endif]-->During the Summer, we experienced some unexplained failures. Nick recently informed me that there were two instances when the temperature in the hall was excessive duw to HVAC failures or door open for long periods of time. Nick
has suggested some additional interlock controls. It would be instructive if someone could check the environmental logs and others since the end of the Spring run.<o:p></o:p></p>
<p class="MsoPlainText" style="margin-left:.5in;text-indent:-.25in;mso-list:l0 level1
lfo1">
<!--[if !supportLists]--><span style="mso-list:Ignore">c)<span style="font:7.0pt "Times New Roman"">
</span></span><!--[endif]-->The last sentence is not correct. Spreading the modules apart will not provide better cooling as the thermal radiative losses are insignificant compared to the convective cooling efficiency.<o:p></o:p></p>
<p class="MsoPlainText" style="margin-left:.5in;text-indent:-.25in;mso-list:l0 level1
lfo1">
<!--[if !supportLists]--><span style="mso-list:Ignore">d)<span style="font:7.0pt "Times New Roman"">
</span></span><!--[endif]-->There is also the possibility of radiation damage on the D2 platform due to changing experimental conditions (prototype tests of the COMCAL and others). This was also brought up by CAEN during maintenance of failed HV controllers.
I have Alexandre D. to look into this in detail from logs of radiation detectors he manages.<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">Best regards,<o:p></o:p></p>
<p class="MsoPlainText">Fernando<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText"><img style="width:11.9166in;height:1.7083in" id="Picture_x0020_1" src="cid:part1.F33BECE0.568A109A@jlab.org" class="" width="1144" height="164"><o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">-----Original Message-----<br>
From: Halld-cal <a class="moz-txt-link-rfc2396E" href="mailto:halld-cal-bounces@jlab.org">
<halld-cal-bounces@jlab.org></a> On Behalf Of Elton Smith<br>
Sent: Friday, November 15, 2019 1:25 PM<br>
To: <a class="moz-txt-link-abbreviated" href="mailto:halld-cal@jlab.org">halld-cal@jlab.org</a><br>
Subject: [Halld-cal] Minutes from yesterday's meeting</p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">Dear collaborators,<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">I have posted the minutes from yesterday's meeting on the wiki at
<a href="https://halldweb.jlab.org/wiki/index.php/Nov_14,_2019_Calorimeter#Minutes" moz-do-not-send="true">
<span style="color:windowtext;text-decoration:none">https://halldweb.jlab.org/wiki/index.php/Nov_14,_2019_Calorimeter#Minutes</span></a>.<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">Cheers, Elton.<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">--<o:p></o:p></p>
<p class="MsoPlainText">Elton Smith<o:p></o:p></p>
<p class="MsoPlainText">Jefferson Lab MS 12H3<o:p></o:p></p>
<p class="MsoPlainText">12000 Jefferson Ave STE 4<o:p></o:p></p>
<p class="MsoPlainText">Newport News, VA 23606<o:p></o:p></p>
<p class="MsoPlainText">(757)269-7625<o:p></o:p></p>
<p class="MsoPlainText">(757)269-6331 fax<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">_______________________________________________<o:p></o:p></p>
<p class="MsoPlainText">Halld-cal mailing list<o:p></o:p></p>
<p class="MsoPlainText"><a href="mailto:Halld-cal@jlab.org" moz-do-not-send="true"><span style="color:windowtext;text-decoration:none">Halld-cal@jlab.org</span></a><o:p></o:p></p>
<p class="MsoPlainText"><a href="https://mailman.jlab.org/mailman/listinfo/halld-cal" moz-do-not-send="true"><span style="color:windowtext;text-decoration:none">https://mailman.jlab.org/mailman/listinfo/halld-cal</span></a><o:p></o:p></p>
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<pre class="moz-quote-pre" wrap="">_______________________________________________
Halld-cal mailing list
<a class="moz-txt-link-abbreviated" href="mailto:Halld-cal@jlab.org">Halld-cal@jlab.org</a>
<a class="moz-txt-link-freetext" href="https://mailman.jlab.org/mailman/listinfo/halld-cal">https://mailman.jlab.org/mailman/listinfo/halld-cal</a></pre>
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