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<p>Folks,</p>
<p>Find the minutes below and at
<a class="moz-txt-link-freetext" href="https://halldweb.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_August_16,_2016#Minutes">https://halldweb.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_August_16,_2016#Minutes</a>
.</p>
<p> -- Mark</p>
<p>_____________________</p>
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<h2 id="firstHeading" class="firstHeading" lang="en"><span
dir="auto">GlueX TOF Meeting, August 16, 2016, </span><span
class="mw-headline" id="Minutes">Minutes</span></h2>
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lang="en">
<p>Present:
</p>
<ul>
<li> <b>FSU</b>: Sasha Ostrovidov</li>
<li> <b>JLab</b>: Fernando Barbosa, Brad Cannon, Paul
Eugenio, Mark Ito (chair), Simon Taylor, Beni Zihlmann</li>
</ul>
<h3><span class="mw-headline"
id="Review_of_minutes_from_the_previous_meeting">Review
of minutes from the previous meeting</span></h3>
<p>We looked over the <a
href="https://halldweb.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_August_9,_2016#Minutes"
title="GlueX TOF Meeting, August 9, 2016">minutes from
August 9</a>.
</p>
<ul>
<li> Although it is expected that the timing is worse
for cosmics runs than for beam data, we do not have a
detailed understanding of the mechanism.</li>
<li> Sasha reported a problem with the cosmic trigger:
the energy threshold is expressed in 16 bits on the
sum of all TOF counters and a single channel can cause
the sum to exceed it. Beni will talk to Sasha about
raising the threshold.</li>
</ul>
<h3><span class="mw-headline" id="TOF_Efficiency">TOF
Efficiency</span></h3>
<p>Beni showed scatter plots of efficiency for two runs:
10439 and 11508.
</p>
<table>
<tbody>
<tr>
<td>
<div class="thumb tright">
<div class="thumbinner" style="width:1200px;"><a
href="https://halldweb.jlab.org/wiki/index.php/File:Run10439_eff.gif"
class="image"><img alt=""
src="cid:part2.E5F997CC.BBD0F69F@jlab.org"
class="thumbimage" height="774"
width="1198"></a>
<div class="thumbcaption">Run 10439</div>
</div>
</div>
</td>
</tr>
<tr>
<td>
<div class="thumb tright">
<div class="thumbinner" style="width:1200px;"><a
href="https://halldweb.jlab.org/wiki/index.php/File:Run11508_eff.gif"
class="image"><img alt=""
src="cid:part4.10F0BFDA.03B70717@jlab.org"
class="thumbimage" height="774"
width="1198"></a>
<div class="thumbcaption">Run 11508</div>
</div>
</div>
</td>
</tr>
</tbody>
</table>
<p>The plots show in the first column the distribution of
track intersection points for tracks which match the
TOF, for the vertical and horizontal paddles. The four
plots in the second and third columns show, clockwise
from top left, the charged track match efficiency for
vertical paddles in 2-D bins of intersection position,
the same for horizontal paddles, the efficiency for TOF
points, and the efficiency in 2-D bins of charged track
momentum versus polar angle.
</p>
<p>Beni also showed efficiency as a function of run number
for five paddle numbers both for horizontal and vertical
plane.
</p>
<p><a
href="https://halldweb.jlab.org/wiki/index.php/File:Paddle_eff_run8_ver2.gif"
class="image"><img alt="Paddle eff run8 ver2.gif"
src="cid:part6.1DF750CF.5D0F9094@jlab.org"
height="474" width="698"></a>
<a
href="https://halldweb.jlab.org/wiki/index.php/File:Paddle_eff_run15_ver2.gif"
class="image"><img alt="Paddle eff run15 ver2.gif"
src="cid:part8.B67697CA.3CA10DDB@jlab.org"
height="474" width="698"></a>
<a
href="https://halldweb.jlab.org/wiki/index.php/File:Paddle_eff_run20_ver2.gif"
class="image"><img alt="Paddle eff run20 ver2.gif"
src="cid:part10.61CE77D6.E092D0DA@jlab.org"
height="474" width="698"></a>
<a
href="https://halldweb.jlab.org/wiki/index.php/File:Paddle_eff_run21_ver2.gif"
class="image"><img alt="Paddle eff run21 ver2.gif"
src="cid:part12.C3EE1480.554B4998@jlab.org"
height="474" width="698"></a>
<a
href="https://halldweb.jlab.org/wiki/index.php/File:Paddle_eff_run5_ver2.gif"
class="image"><img alt="Paddle eff run5 ver2.gif"
src="cid:part14.666A6E5A.16D5F589@jlab.org"
height="474" width="698"></a>
</p>
<p>Paddles 8 and 15 do not show much of an effect, but
paddles 20 and 21 show unstable efficiencies near the
end of the run. These are the ones closest to the beam.
Paddle 5, although far from the beam, shows instability.
This is not understood at present. The inefficiencies
may be a combination of reduced gain at high rates and
simply two-pulse resolution probability being reduced at
high rate.
</p>
<h3><span class="mw-headline"
id="TDC_Integral_Non-Linearity_Correction_Calibration">TDC
Integral Non-Linearity Correction Calibration</span></h3>
<p>Fernando reported that Ed Jastrzembski and Bryan Moffit
are working on a scheme to obtain a non-linear
correction for the CAEN TDCs. The TDCs are shipped from
the factory with the correction pre-loaded, but that
correction is based on a 40 MHz clock driving the
boards; we run with 41.667 MHz. Turns out that the
correction depends on the clock rate. The correction is
different for each chip, but each chip services several
channels.
</p>
<p>The exact scheme for obtaining and downloading new
calibration tables have not been worked out yet. The
data will be obtained in situ in the Hall. We will need
to schedule time for doing this before the run.
</p>
<h3><span class="mw-headline" id="NIM_Paper">NIM Paper</span></h3>
<p>Paul will be turning to the NIM paper as one of his
high priority tasks in the coming weeks, as well as
looking into fixtures for gluing new tubes on the
counters if that becomes necessary.
</p>
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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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