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Production running is completed as of Noon on Sunday June 24th.
Systematic studies aimed at understanding/measuring the positron
beam characteristics commenced Sunday afternoon and ran through to
Monday Morning.<br>
<br>
We will have a 3:30pm meeting to discuss the path forward. Here
are some of the open issues:<br>
<ol>
<li>Positron Energy profile, the round scintillator gave a
response that was dependent on the incident position. <br>
</li>
<ol>
<li>Change to a rectangular scintillator : Use the three
cosmic paddles</li>
<li>Change to a rectangular scintillator: fabricate one</li>
<li>Both 1 and 2 are in progress......<br>
</li>
</ol>
<li>Positron Position Profile: Fiber Array measurements showed a
static distribution with respect to beam energy, solenoid
settings. Need to establish if this device is measuring signal
or just background</li>
<ol>
<li>Desire more beam time (1 to 2 hours) to check with electron
beam</li>
</ol>
<li>Positron bunch length: TDC and trigger yields a value of
1.3nsec. Even for electron beam.</li>
<ol>
<li>punt on this.</li>
</ol>
<li>Mott measurements: Originally on the schedule, may be
deferred for a day.</li>
</ol>
<p>Please come to the 3:30pm meeting in MCC for what looks to be a
healthy discussion. <br>
</p>
<p>Cheers,<br>
Arne<br>
</p>
<pre class="moz-signature" cols="72">--
Arne Freyberger
Director of Accelerator Operations
Jefferson Lab Office: (757) 269-6268
12000 Jefferson Avenue Cell: (757) 876-6289
Newport News, VA 23606 Email: <a class="moz-txt-link-abbreviated" href="mailto:freyberg@jlab.org">freyberg@jlab.org</a>
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