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Folks,<br>
<br>
Please find the minutes below and at<br>
<br>
<a class="moz-txt-link-freetext" href="https://halldweb.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_April_14,_2015#Minutes">https://halldweb.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_April_14,_2015#Minutes</a><br>
<br>
-- Mark<br>
________________________________________________<br>
<br>
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<div id="content" class="mw-body" role="main"> <span dir="auto">GlueX
TOF Meeting, April 14, 2015</span><br>
<div id="bodyContent" class="mw-body-content"><span
class="mw-headline" id="Minutes">Minutes</span><br>
<div id="mw-content-text" dir="ltr" class="mw-content-ltr"
lang="en">
<br>
Present:
<br>
<ul>
<li> <b>FSU</b>: Hussein Al Ghoul, Brad Cannon, Sasha
Ostrovidov, Aristeidis Tsaris</li>
<li> <b>JLab</b>: Eugene Chudakov, Mark Ito (chair),
Simon Taylor, Beni Zihlmann</li>
</ul>
<br>
<span class="mw-headline" id="Calibration_Status">Calibration
Status</span><br>
<br>
Sasha showed a <a rel="nofollow" class="external text"
href="http://128.186.19.133/%7Eostrov/tof/20150414/">page</a>
with a plot where he compares longitudinal position
measured by end-to-end time differences in a chosen
counter (one of the thin counters) with the known
geometric position of counters in the other layer, where
the counters are perpendicular to the chosen counter.
Details of cuts and criteria are described on the page.
There is a clear correlation in the position of the two
measurement methods, but the plot is dominated by
uncorrelated hits, with most of those coming from near the
beam line, as expected.
<br>
There were several suggestions on how to over come this
background.
<br>
<br>
Beni has a new approach to calibration that depends on
starting by calibrating mean times and time differences
and then transforming the results to constants to apply to
individual channels. Simon is working on evaluating these
new constants. Beni will give is a talk on his method at a
future meeting.
<br>
<br>
<span class="mw-headline" id="TDC_Time-Scale">TDC
Time-Scale</span><br>
<br>
Paul Mattione has discovered that our nominal setting of
25 ps for the time bin of the CAEN TDCs does not give the
correct separation between successive RF timing pulses. He
is seeing a time bin about 7% smaller.
<br>
<br>
Added in press: careful reading of the CAEN manual
indicates a time bin width of 23.4375 consistent with what
Paul found.
<br>
<br>
<span class="mw-headline" id="Meetings">Meetings</span><br>
<br>
Sasha Ostrovidov will start attending the Wednesday
bi-weekly calibration meetings.
<br>
<br>
Mark will remind Paul about the upcoming Run Planning
meeting on Thursday.
<br>
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<li id="lastmod"> This page was last modified on 15 April
2015, at 20:46.</li>
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-- Mark M. Ito, Jefferson Lab, <a class="moz-txt-link-abbreviated" href="mailto:marki@jlab.org">marki@jlab.org</a>, (757)269-5295
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