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Hi Mauri,<br>
<br>
I would like to increase oil level in the bubbler, that would reduce
gas usage, but it may also mess up R3S5 DC location. Yes, you are
correct, the major gas loss is from the bubbler due to ambient
pressure changes. This loss is >> leaks out the box.<br>
<br>
So far, so good, on this test. Once we have evidence of proper
detector operation, we will also have proof of concept and can
estimate typical gas usage due to ambient pressure transients with a
"tight" box..<br>
<br>
George<br>
<br>
<div class="moz-cite-prefix">On 2/6/2018 2:15 PM, Maurizio Ungaro
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CA6EF3C7-7F1C-4EBF-AF56-49E116E539BE@jlab.org">
<meta http-equiv="Content-Type" content="text/html;
charset=windows-1252">
Hi George,
<div class=""><br class="">
</div>
<div class="">Do you think the 2.1 limit can be increased or is it
too dangerous?</div>
<div class="">It seems to me that c4f10 in the bubbler may be
"the" main cause of gas losses. Please correct if I'm wrong.</div>
<div class=""><br class="">
</div>
<div class="">The scale stayed at 71 for almost 3 days. This
indicates a leak rate of 0.3 Kg / day, which is what was
predicted, however I believe the box performs even better than
this since David patched a couple of places.</div>
<div class=""><br class="">
</div>
<div class="">Results on the gas on the data coming soon, I
apologize it's taking so long.</div>
<div class=""><br class="">
</div>
<div class="">Thanks,</div>
<div class="">Mauri</div>
<div class=""><br class="">
</div>
<div class=""><br class="">
</div>
<div class=""><br class="">
</div>
<div class=""><img apple-inline="yes"
id="CA08B002-88F4-4B70-9653-230439CA2AB2"
src="cid:part1.A9536393.18302134@jlab.org" class=""></div>
<div class=""><br class="">
<div>
<blockquote type="cite" class="">
<div class="">On Feb 5, 2018, at 10:48 AM, George Jacobs
<<a href="mailto:jacobsg@jlab.org" class=""
moz-do-not-send="true">jacobsg@jlab.org</a>> wrote:</div>
<br class="Apple-interchange-newline">
<div class="">
<meta http-equiv="content-type" content="text/html;
charset=windows-1252" class="">
<div text="#000000" bgcolor="#FFFFFF" class=""> Hi Mauri,<br
class="">
<br class="">
Current Status -From the pressure strip chart, it looks
as if the detector has been full since around noon on 29
Jan. The best way to determine the detector fill is
from the detector monitor or event plots.<br class="">
<br class="">
<div class="">Gas Usage - From the gas supply remaining
as indicated by the scale readout, usage since 30 Jan
is 3 kg or 0.5 kg per day<br class="">
</div>
<div class=""><br data-mce-bogus="1" class="">
</div>
<div class="">The detector pressure is limited to 2.1"wc
by the bubblers, ambient pressure changes or
transients are a significant factor in gas loss.<br
data-mce-bogus="1" class="">
</div>
<div class=""><br data-mce-bogus="1" class="">
</div>
<div class="">I have attached the strip chart showing
the detector pressure and ambient pressure history.<br
data-mce-bogus="1" class="">
</div>
<div class=""><br data-mce-bogus="1" class="">
</div>
<div class="">Blue line is gas pressure at the bottom of
the detector.<br data-mce-bogus="1" class="">
</div>
<div class="">Brown line show pressure at the bubbler.<br
data-mce-bogus="1" class="">
</div>
<div class="">Green line is ambient pressure.<br
data-mce-bogus="1" class="">
</div>
<div class=""><br data-mce-bogus="1" class="">
</div>
<div class="">22 Jan - gas flow started @ 0.5 slm<br
data-mce-bogus="1" class="">
</div>
<div class="">29 Jan - Detector volume indicates it is
FULL<br data-mce-bogus="1" class="">
</div>
<div class="">29 Jan - gas flow reduced to 0.1 slm<br
data-mce-bogus="1" class="">
</div>
<div class="">30 Jan - gas flow reduced to 0.065 slm (65
sccm)<br data-mce-bogus="1" class="">
</div>
<div class="">31 Jan - Gas supply programmed to shut off
when pressure reaches 2.02"wc and turn back on when it
falls to 1.95"wc<br class="">
<br class="">
<span id="cid:part1.23361C6D.01722014@jlab.org"><LTCC-S5-Press-05Feb2018-2.png></span><br
data-mce-bogus="1" class="">
</div>
<div class=""><br data-mce-bogus="1" class="">
</div>
<div class="">Detector pressure rises and falls as
ambient pressure changes. Ambient pressure changes are
significant when compared with detector pressure. </div>
<div class=""><br data-mce-bogus="1" class="">
</div>
<div class="">When ambient pressure decreases, detector
differential pressure increases. When the detector
pressure exceeds 2.1"wc, gas is lost out the bubbler.
This gas loss is significant.<br data-mce-bogus="1"
class="">
</div>
<div class=""><br data-mce-bogus="1" class="">
</div>
<div class="">When ambient pressure increases, detector
differential pressure decreases. The magnitude of the
pressure decrease follows that of the ambient pressure
change and is countered by the gas flow. Current gas
flow is set at 65 sccm, the minimum flow the mass flow
controllers can achieve. A higher flow would help
minimize the magnitude of the pressure decrease. A
higher flow would also increase gas usage or loss out
the bubbler, during an ambient pressure decrease.<br
data-mce-bogus="1" class="">
</div>
<div class=""><br data-mce-bogus="1" class="">
</div>
<div class="">Determining the maintenance gas flow rate
is a balancing act. Increasing the gas flow would
minimize the detector pressure decrease during ambient
pressure transients, but would also increase gas usage
or loss rate. A good reason to increase gas flow would
be to verify proper detector operation at the current
flow rate.<br data-mce-bogus="1" class="">
</div>
<div class=""><br data-mce-bogus="1" class="">
</div>
<div class="">Everything looks good from what the
pressure strip chart shows. Has anyone looked at the
events from beam as yet?<br data-mce-bogus="1"
class="">
</div>
<div class=""><br data-mce-bogus="1" class="">
</div>
George<br class="">
<br class="">
<pre class="moz-signature" cols="72">--
George Jacobs
Jefferson Lab (TJNAF)
STE 12
12000 Jefferson Ave.
Newport News, VA 23606
(office) 757-269-7115
(cell) 757-876-0480
(email) <a class="moz-txt-link-abbreviated" href="mailto:jacobsg@jlab.org" moz-do-not-send="true">jacobsg@jlab.org</a>
(website) <a class="moz-txt-link-freetext" href="https://userweb.jlab.org/%7Ejacobsg" moz-do-not-send="true">https://userweb.jlab.org/~jacobsg</a></pre>
</div>
</div>
</blockquote>
</div>
<br class="">
</div>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
George Jacobs
Jefferson Lab (TJNAF)
STE 12
12000 Jefferson Ave.
Newport News, VA 23606
(office) 757-269-7115
(cell) 757-876-0480
(email) <a class="moz-txt-link-abbreviated" href="mailto:jacobsg@jlab.org">jacobsg@jlab.org</a>
(website) <a class="moz-txt-link-freetext" href="https://userweb.jlab.org/~jacobsg">https://userweb.jlab.org/~jacobsg</a></pre>
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