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Folks,<br>
<br>
Please find the meeting minutes below and at
<a class="moz-txt-link-freetext" href="http://tinyurl.com/hr5s9ym">http://tinyurl.com/hr5s9ym</a> .<br>
<br>
-- Mark<br>
____________________________________________<br>
<br>
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<h1 id="firstHeading" class="firstHeading" style="font-weight:
bold;" lang="en"><span dir="auto">GlueX Start Counter Meeting,
March 24, 2016, </span><span class="mw-headline"
id="Minutes">Minutes</span></h1>
<div id="bodyContent" class="mw-body-content">
<div id="mw-content-text" dir="ltr" class="mw-content-ltr"
lang="en">
<p style="widows: 3; orphans: 3; margin: 1em 0px;
line-height: 1.2em;">The meeting came to order at 10:00
am.</p>
<p style="widows: 3; orphans: 3; margin: 1em 0px;
line-height: 1.2em;">Present:</p>
<ul style="list-style-type: square;">
<li><b>FIU</b>: Mahmoud Kamel, Eric Pooser</li>
<li><b>JLab</b>: Mark Ito (chair), Simon Taylor, Beni
Zihlmann</li>
</ul>
<h3 style="page-break-after: avoid; font-weight: bold;"><span
class="mw-headline" id="Announcements">Announcements</span></h3>
<p style="widows: 3; orphans: 3; margin: 1em 0px;
line-height: 1.2em;">Beam delivery to Hall D is scheduled
for Sunday, March 27.</p>
<h3 style="page-break-after: avoid; font-weight: bold;"><span
class="mw-headline"
id="Review_minutes_from_the_last_meeting">Review<span
class="Apple-converted-space"> </span><a
href="https://halldweb.jlab.org/wiki/index.php/GlueX_Start_Counter_Meeting,_January_28,_2016#Minutes"
title="GlueX Start Counter Meeting, January 28, 2016"
style="color: rgb(85, 34, 0); padding: 0px !important;
text-decoration: underline; background: transparent;">minutes
from the last meeting</a></span></h3>
<ul style="list-style-type: square;">
<li>No progress on the NIM paper or the TDR since the last
meeting.</li>
</ul>
<h3 style="page-break-after: avoid; font-weight: bold;"><span
class="mw-headline" id="Calibration_Update">Calibration
Update</span></h3>
<p style="widows: 3; orphans: 3; margin: 1em 0px;
line-height: 1.2em;">Mahmoud gave an update on time
propagation delay calibration focusing on a comparison
between data and simulation. See<span
class="Apple-converted-space"> </span><a rel="nofollow"
class="external text"
href="http://argus.phys.uregina.ca/cgi-bin/private/DocDB/ShowDocument?docid=2980"
style="color: inherit !important; padding: 0px
!important; text-decoration: inherit !important;
background: transparent;">his slides</a><span
class="Apple-converted-space"> </span>for the plots and
details.</p>
<p style="widows: 3; orphans: 3; margin: 1em 0px;
line-height: 1.2em;">He showed the results of the
calibration for each section of the start counter for a
sample of recent data (run 10496) and the sim1 simulated
data. Differences are seen mainly in the nose section,
where fits do not represent the data very well.</p>
<p style="widows: 3; orphans: 3; margin: 1em 0px;
line-height: 1.2em;">The overall timing resolution is 270
ps for data, but 370 ps for simulation. To start with for
simulation, there is 300 ps of smearing introduced by
mcsmear but the reason for poorer resolution than that is
unclear. Mahmoud may try to go back to a simpler
propagation delay scheme that uses a constant velocity
rather than the section dependent velocity
(straight/bend/nose) that is the current default.</p>
<h3 style="page-break-after: avoid; font-weight: bold;"><span
class="mw-headline" id="Resolutions_in_mcsmear"><a
href="https://halldweb.jlab.org/wiki/index.php/Mcsmear_20160323#SC_Resolutions"
title="Mcsmear 20160323" style="color: rgb(85, 34, 0);
padding: 0px !important; text-decoration: underline;
background: transparent;">Resolutions in mcsmear</a></span></h3>
<p style="widows: 3; orphans: 3; margin: 1em 0px;
line-height: 1.2em;">Sean showed monitoring plots again
comparing data and Monte Carlo. He has collected a few
interesting plots for other subsystems as well. The start
counter section shows a large number of RF-bucket
mis-identifications for simulation in the plots from which
resolution numbers are extracted. The reasons are not
clear; RF bucket selection for the data looks clean.</p>
<h3 style="page-break-after: avoid; font-weight: bold;"><span
class="mw-headline" id="mcsmear_parameters"><a
href="https://halldweb.jlab.org/wiki/index.php/Mcsmear_updates#START_COUNTER"
title="Mcsmear updates" style="color: rgb(85, 34, 0);
padding: 0px !important; text-decoration: underline;
background: transparent;">mcsmear parameters</a></span></h3>
<p style="widows: 3; orphans: 3; margin: 1em 0px;
line-height: 1.2em;">We discussed the parameters used by
mcsmear to introduce detector effects to the start counter
hits. The first line in the table is the 300 ps mentioned
in the discussion of Mahmoud's slides (above). Sean
proposed using the measured values of the resolution as
recorded in the CCDB to do time smearing with a
channel-dependent width.</p>
<p style="widows: 3; orphans: 3; margin: 1em 0px;
line-height: 1.2em;">We discussed how the other parameters
should be measured and indeed whether these are the best
set of parameters to use. Mark and Simon will make a
proposal on how the various effects should be parametrized
and how those parameters should be measured. They will
report back to the group at a future meeting.</p>
<h3 style="page-break-after: avoid; font-weight: bold;"><span
class="mw-headline" id="Multiple_ADC_hits_checks">Multiple
ADC hits checks</span></h3>
<p style="widows: 3; orphans: 3; margin: 1em 0px;
line-height: 1.2em;">Sean reminded us that now were are
running with npeaks = 3 in the FADC-250s and there is a
need to study the matching of ADC and TDC hits with this
new scheme.</p>
<h3 style="page-break-after: avoid; font-weight: bold;"><span
class="mw-headline" id="Efficiency_measurement">Efficiency
measurement</span></h3>
<p style="widows: 3; orphans: 3; margin: 1em 0px;
line-height: 1.2em;">Paul Mattione had commented on
Mahmoud's presentation of start counter efficiency at the<span
class="Apple-converted-space"> </span><a
href="https://halldweb.jlab.org/wiki/index.php/March_9,_2016_Calibration#Minutes"
title="March 9, 2016 Calibration" style="color: rgb(85,
34, 0); padding: 0px !important; text-decoration:
underline; background: transparent;">Calibration Meeting</a>.
There appears to have been some skepticism expressed due
to the use of protons to measure efficiency. Mahmoud
pointed out the he gets the same results independent of
the particle species. We agreed to circulate Paul's points
and Mahmoud's response and discuss the issues at the next
meeting.</p>
<h3 style="page-break-after: avoid; font-weight: bold;"><span
class="mw-headline" id="Run_Issues">Run Issues</span></h3>
<p style="widows: 3; orphans: 3; margin: 1em 0px;
line-height: 1.2em;">There was one round of pedestal
adjustment for the FADCs early in the run by Eric and
Sergey Furletov. Nothing has been done since. Beni
advocates doing another round before we start running
again, and not just for the start counter.</p>
<p style="widows: 3; orphans: 3; margin: 1em 0px;
line-height: 1.2em;">The meeting adjourned at 11:05 am.</p>
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<li id="lastmod">This page was last modified on 24 March 2016,
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<br>
<pre class="moz-signature" cols="72">--
<a class="moz-txt-link-abbreviated" href="mailto:marki@jlab.org">marki@jlab.org</a>, (757)269-5295
</pre>
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