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Gluons,<br>
<br>
Please find the minutes below and at<br>
<br>
<a class="moz-txt-link-freetext" href="https://halldweb1.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_November_18,_2014#Minutes">https://halldweb1.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_November_18,_2014#Minutes</a><br>
<br>
-- Mark<br>
________________________________________________<br>
<br>
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GlueX TOF Meeting, November 18, 2014<br>
<div id="bodyContent"><span class="mw-headline" id="Minutes">Minutes</span><br>
<br>
Present:
<br>
<ul>
<li> <b>FSU</b>: Hussein Al Ghoul, Paul Eugenio, Sasha
Ostrovidov, Aristeidis Tsaris
</li>
<li> <b>JLab</b>: Mark Ito (chair)
</li>
</ul>
<br>
<span class="mw-headline" id="Commissioning_Plan_Review">Commissioning
Plan Review</span><br>
<br>
Paul was prepared to present the <a
href="https://hdops.jlab.org/wiki/index.php/Time-of-Flight_System_Commissioning"
class="external text" rel="nofollow">commissioning run
plan</a> for the TOF at this morning's Run Coordination
Meeting, but the agenda did not include this discussion. We
went over the components of our request:
<br>
<ol>
<li> For calibration we need straight tracks (no field)
going through the TOF.
</li>
<li> We need a TOF-based trigger to illuminate the corners
of the TOF array that are beyond the FCAL.
</li>
<li> We need running in two target positions:
<ol>
<li> Nominal position to allow tracking with the FDC.
</li>
<li> Forward position to allow tracks to hit the
corners of the TOF. In the nominal position parts of
the TOF are shadowed by the solenoid iron.
</li>
</ol>
</li>
<li> High-rate running to assess TOF performance under
those conditions. For this we want as thick a target and
as high a beam rate as possible.
</li>
</ol>
<br>
<span class="mw-headline" id="FADC_Voltage_Range">FADC
Voltage Range</span><br>
<br>
We have been running with a full range of 1 Volt so far. All
tests at FSU were done with the 2-V range. Sasha has
reported 30% of the pulses with overflows in the last cosmic
runs he took some weeks ago. Fernando Barbosa has questioned
whether we need to make this change. It is possible that the
cosmic data has much larger average pulse height than beam
data due to the high number of vertical cosmics. Sasha will
look at the beam data from last night to check whether we
want to proceed with changing the FADC range.
<br>
<br>
<span class="mw-headline" id="TDC_Timing">TDC Timing</span><br>
<br>
The upgrade to the firmware that we discussed at the last
TOF meeting has still not been installed. Sascha Somov had
told Paul that it would be in by now. In addition we have
still not seen the trigger signal in the TDC data. We need
to continue to pursue this issue.
<br>
Sasha O. is concerned that there might be timing jitter from
board-to-board in the system due to the trigger pulse being
presented to different boards at different times. Mark
stated that this should not happen; if it occurs in the data
then we need to address it, but we should push ahead on the
assumption that there are no random time shifts between any
two channels in the CAEN TDC crate.
<br>
<br>
<span class="mw-headline" id="Calibration">Calibration</span><br>
<br>
We have transitioned to pursuing beam-based calibration
only.
<br>
The last run examined, run 995, had no TDC data for the TOF.
The read-out window was not adjusted when going from the
stand-alone TOF trigger to the global FCAL trigger. Last
Thursday Paul adjusted the window. Sasha O. will look at the
data taken yesterday and see if the TDC data is present.
<br>
There is still confusion about the pulse-integral data. The
behavior of the data seems different than that of the raw
mode data. The effect of NSB/NSA on the integral data is not
clear. Mark will try to find the document describing the
algorithm used by the firmware. It would be helpful to have
data with the full raw pulse and the pulse-integral summary
in the same event so an offline check can be made.
<br>
<br>
<span class="mw-headline" id="Equipment_Loan">Equipment Loan</span><br>
<br>
Paul is looking through the items and will return those that
are not needed for reading out the mini-TOF.
<br>
<br>
<span class="mw-headline" id="Action_Items">Action Items</span><br>
<ol>
<li> Look at overflow fraction in beam-based FADC data.
</li>
<li> Request the TS change to synch the CAEN TDC system
clock to the global system clock.
</li>
<li> Look for TDC hits in the read-out window of beam
data.
</li>
<li> Get the document on the FADC pulse-integral
algorithm.
</li>
<li> Ask for raw and summary FADC data in the same event.
</li>
<li> Assess need for loaned equipment.
</li>
</ol>
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<pre class="moz-signature" cols="72">--
Mark M. Ito, Jefferson Lab, <a class="moz-txt-link-abbreviated" href="mailto:marki@jlab.org">marki@jlab.org</a>, (757)269-5295</pre>
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