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The minutes of yesterday's HPS controls minutes have been posted: <br>
<br>
<a class="moz-txt-link-freetext" href="https://confluence.slac.stanford.edu/display/hpsg/2013.07.22+Biweekly">https://confluence.slac.stanford.edu/display/hpsg/2013.07.22+Biweekly</a><br>
<br>
Hovanes. <br>
<br>
<br>
<h2>Minutes</h2>
<p>Present at JLab: Hovanes, Nerses, Krister, Stepan, F.X.</p>
<p>Present at SLAC: Sho, Takashi</p>
<h3><a name="2013.07.22Biweekly-Motorizedapplications"></a>Motorized
applications</h3>
<ul>
<li>Takashi described the HPS-specific <a
href="https://confluence.slac.stanford.edu/download/attachments/141334487/StepperMotor.pptx?version=1&modificationDate=1374510431000">applications
requiring stepper motor control.</a>
<ul>
<li>Target (new stage)
<ul>
<li>2 foils and out position. May increase the number of
foils to 5.</li>
<li>2 limit switches, low precisions, ~100um, always use
reset with limit switch on power loss</li>
<li>May need to put a wire on the stick for a harp scan
after first chicane</li>
</ul>
</li>
<li>Collimator (new stage)
<ul>
<li>2 collimators and out position. May increase to 4.</li>
<li>adjustable 50um, need to monitor some rates to find
optimal position. Can implement a scan also, </li>
<li>adjustment will need to be redone every time the
collimator is retracted.</li>
<li>Hovanes wanted to have specs of the stage (uni- and
bi-directional reproducibility, accuracy, smallest
increment)</li>
</ul>
</li>
<li>SVT motion (2 new stages)
<ul>
<li>Nominal run positions and out position</li>
<li>Support plates are horizontal in the nominal run
position. </li>
<li>Nominal run position need to have 25 um
reproducibility.</li>
<li>It would be good to have the specs for the stages to
see how to achieve the reproducibility requirement.</li>
<li>The encoder reset is suggested at the innermost end,
but can be done at the outer position if the
reproducibility is not compromised. </li>
<li>The limit switch will be at 450um from the beam, the
"hard stop" at 400um from the beam. The nominal run
position at 500um from the beam.</li>
</ul>
</li>
<li>SVT scan (same stages as SVT motion)
<ul>
<li>Two crossed wires on each frame. One horizontal, the
other one at a small angle.</li>
<li>The separation between the wires is on the order of a
few centimeters at a vertical plane passing through the
beam.</li>
<li>Move the support plates individually and record the
rates in some scalers. Find positions where the rates
are identical to center the beam in SVT. </li>
<li>The possible candidates for the detectors are a
dedicated halo counter somewhere in the HPS setup or
ECAL counters.</li>
<li>The range of the scan, the speed of scanning needs to
be determined depending on what detectors we use.</li>
</ul>
</li>
<li>Sometime in mid-September the description of these
applications will be final or close to final.</li>
<li>There are other motor applications as well: 2C21, 2C24,
2CH00, beam blocker. Total 8 motors for HPS: 2 on space
frame, 6 near beam dump alcove. </li>
</ul>
</li>
</ul>
<h3><a name="2013.07.22Biweekly-MagnetPowerSupplies"></a>Magnet
Power Supplies</h3>
<ul>
<li>Krister and Stepan discussed the magnet power supply controls
<ul>
<li>We will need the power supplies for: Moeller quads, Tagger
magnet, minitorus, Pair spectrometer.</li>
<li>Krister pointed out that a lot of controls cabling,
including magnet power supplies have been taken apart. This
can potentially turn into a major headache.</li>
<li>It might be easier to create new controls for some of them
rather than to try to recreate what was there before.</li>
<li>Stepan and Krister will go into the hall to see what is
still there.</li>
</ul>
</li>
</ul>
<h3><a name="2013.07.22Biweekly-ECALVoltages"></a>ECAL Voltages</h3>
<ul>
<li>No update on ECAL HV/LV, the motherboards is still being
finalized, and we ran out of time.</li>
</ul>
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