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<p>Find the minutes below and at <a class="moz-txt-link-freetext" href="https://goo.gl/V1JeDY">https://goo.gl/V1JeDY</a> .</p>
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<h1 id="firstHeading" class="firstHeading" lang="en"><span
dir="auto">GlueX TOF Meeting, August 2, 2016, </span><span
class="mw-headline" id="Minutes">Minutes</span></h1>
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<p>Present:
</p>
<ul>
<li> <b>FSU</b>: Sasha Ostrovidov</li>
<li> <b>JLab</b>: Mark Ito (chair), Simon Taylor, Beni
Zihlmann</li>
</ul>
<h3><span class="mw-headline" id="PMT_order">PMT order</span></h3>
<ul>
<li> Mark received a <a rel="nofollow" class="external
text"
href="https://www.jlab.org/Hall-D/gluex_secure/procurements/TOF_PMT/H10534%20MOD.pdf">quote
from Hamamatsu</a> for more extra spare PMTs].</li>
<li> Beni remarked that 24 PMTs was chosen to cover the
possibility of replacing the innermost counters that
have the highest rate.</li>
<li> At Eugene's suggestion, we will add 6 more tubes to
the order bringing the total to 30, just in case they
are needed.</li>
</ul>
<h3><span class="mw-headline" id="Cosmic_data">Cosmic data</span></h3>
Beni has taken more cosmic data, this time at 1200 V on
the tubes. He is now requiring an ADC and a TDC hit on
both ends of the counter, with all 4 hits in time with
each other.
<div class="thumb tright">
<div class="thumbinner" style="width:302px;"><a
href="https://halldweb.jlab.org/wiki/index.php/File:Run11721_1200V_paddle12_plane2.gif"
class="image"><img alt=""
src="cid:part2.64AEAF1C.720D9F44@jlab.org"
class="thumbimage"
srcset="/wiki/images/thumb/2/25/Run11721_1200V_paddle12_plane2.gif/450px-Run11721_1200V_paddle12_plane2.gif
1.5x,
/wiki/images/thumb/2/25/Run11721_1200V_paddle12_plane2.gif/600px-Run11721_1200V_paddle12_plane2.gif
2x" height="212" width="300"></a>
<div class="thumbcaption">1200 V, paddle 12 of
horizontal plane</div>
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<div class="thumbinner" style="width:302px;"><a
href="https://halldweb.jlab.org/wiki/index.php/File:Run11721_1200V_paddle21_plane2.gif"
class="image"><img alt=""
src="cid:part4.A2BFC58D.2EC937FD@jlab.org"
class="thumbimage"
srcset="/wiki/images/thumb/8/8a/Run11721_1200V_paddle21_plane2.gif/450px-Run11721_1200V_paddle21_plane2.gif
1.5x,
/wiki/images/thumb/8/8a/Run11721_1200V_paddle21_plane2.gif/600px-Run11721_1200V_paddle21_plane2.gif
2x" height="212" width="300"></a>
<div class="thumbcaption">1200 V, paddle 21 of
horizontal plane</div>
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<ul>
<li> The new requirements clean up a lot of the noise
seen at low amplitude in the plots from the last
meeting, though a noise band is still visible.</li>
<li> The effect on time resolution is still open. Trying
to time one layer against the other (crossed) layer is
not giving good results. Beni will try the same
technique with higher voltages to see if that makes
any difference.</li>
<li> Sasha pointed out that we have to look at
efficiency as well, though that may may be hard to
asses with cosmic data.</li>
</ul>
<h3><span class="mw-headline"
id="PMT_currents_during_the_Spring_2016_run">PMT
currents during the Spring 2016 run</span></h3>
<p>Beni made some estimates based on data we took in the
Spring. Note that the recommended maximum current is 100
μA and we want to be well below that.
</p>
<ul>
<li> paddle 14, up, MIP at 900 counts => 450 mV peak,
assuming triangle pulse => 1.4×10<sup>-10</sup>
C/pulse. At 22 kHz => 3 μA.</li>
<li> paddle 2, 600 kHz, => 85 μA, yikes!</li>
</ul>
<h3><span class="mw-headline" id="Next_Meeting">Next
Meeting</span></h3>
<p>We will meet next week in our normal time slot. We will
discuss the run plan for re-commissioning the TOF.
</p>
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<li id="lastmod"> This page was last modified on 3 August
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<pre class="moz-signature" cols="72">--
<a class="moz-txt-link-abbreviated" href="mailto:marki@jlab.org">marki@jlab.org</a>, (757)269-5295
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