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<b>Daily RC Report 5/29:</b><br>
Efforts over the last shifts have focused on the collection process and
detector setup to measure and distinguish both e- and e+. Last SWING
began with Ebeam~6MeV/c and extended e- collection to ~first systematic
effort to collect e+ and provide a signal for detector setup. A first
pass collect of e+ at 4MeV/c was performed and the spectra is perhaps
first indication of the positron signal exiting the vacuum window.
However at the end of SWING the E1 detector was removed to facilitate
setup of the Compton detector (PMT5) in coincidence w/ TS1. Because
the efficiency of Compton rate to positron rate is ~1E-3 the initial
setup in e+ mode was later switched to degraded e- in order to help
determine the TS1/PMT5 coincidence. On last DAY we performed fiber
array detector checkout with beam; there was some signal in vertical
array, but detector is not ready to be used yet. Afterward, we
increased the beam energy to ~8MeV/c production and characterized
collection of e- and e+ using T1=0.1mm W and beam currents up to 5
microAmps. The target performed fine and vacuum level remained below
~5E-8 Torr. At the beginning of SWING tests to repeat characterization
w/ T1=1.0mm W were in process. The goal is to learn that we can
systematically recover yields of e- or e+ using similar conditions of
target, beam current and magnet settings, such that detector
commissioning and calibration may proceed.<br>
<br>
<b>Noteworthy items:</b><br>
1. I will prepare a brief RC report for the Wed 8am meeting, also when
Eric takes over as RC<br>
2. Spectrometer PS occasionally trips off on HV fault during polarity
reversal; must go to ISB to reset PS<br>
3. The annihilation detector (right) is again working and installed.<br>
<br>
<b>Next 24 hours:</b><br>
<br>
Tuesday, 5/29 - SWING SL=Freyberger<br>
<blockquote>Using P=8MeV/c repeat collection study of degraded e- and
e+ from T1=1mm W<br>
Setup e- or e+ conditions for OWL optimization of coincidence between
TS1 & PMT5<br>
</blockquote>
Wednesday, 5/30 - OWL SL=Suleiman<br>
<blockquote>Optimization of conincidence between TS1 & PMT5 w/ e-
and e+<br>
</blockquote>
Wednesday, 5/30 - DAY, SL=Grames<br>
<blockquote>Further optimize e- and e+ collection vs. collimator
settings<br>
Use steering magnet and PMT's to deflect e- and e+<br>
<br>
</blockquote>
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