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<h1 class="title">B-team Meeting Notes</h1>
<div id="outline-container-1" class="outline-2">
<h2 id="sec-1"><span class="section-number-2">1</span> <span
class="timestamp-wrapper"> <span class="timestamp">2009-12-23 Wed
13:01</span></span> No Meeting This Week </h2>
<div class="outline-text-2" id="text-1">
<p>Happy Holidays!!! See you next year!
</p>
</div>
</div>
<div id="outline-container-2" class="outline-2">
<h2 id="sec-2"><span class="section-number-2">2</span> <span
class="timestamp-wrapper"> <span class="timestamp">2009-12-17 Thu
13:30</span></span> Notes </h2>
<div class="outline-text-2" id="text-2">
<p>Due to Hall-A collaboration meeting the BTEAM meeting has been moved
to Thursday at 1:30pm MCC conference room.
</p>
</div>
<div id="outline-container-2.1" class="outline-3">
<h3 id="sec-2.1"><span class="section-number-3">2.1</span> Hall-B Dark
matter experiment <span class="tag"><span class="Stepanyan">Stepanyan</span></span></h3>
<div class="outline-text-3" id="text-2.1">
<p>Stepan will introduce us to a proposal for a dark matter search in
Hall-B that will likely need some optics support.
</p>
<p>
Both Hall-A and Hall-B have proposals going to PAC. Same SLAC group.
</p>
<p>
Various cosmic ray and satellite measurements are hard to explain with
standard cosmological models.
</p>
<p>
Two possible scenarios: between the tagger exit and tagger dump or
somewhere in the Moller region.
</p>
<p>
Moller region will require a combined optics. The present proposal is
to use the Moller quads to pull out the e<sup>-e</sup><sup>-e</sup>^+
triplets into a
calorimeter. Stepan needs help in verifying that the Moller quads can
be used in this fashion and that the primary electron beam can be
cleanly transported to the Tagger dump.
</p>
<p>
There will be a collaboration meeting on January 21 and 22, Stepan has
requested that some knowledgeable beam transport (Bteam) staff attend.
</p>
</div>
</div>
<div id="outline-container-2.2" class="outline-3">
<h3 id="sec-2.2"><span class="section-number-3">2.2</span> PRex
requirements <span class="tag"><span class="ATTACH">ATTACH</span></span></h3>
<div class="outline-text-3" id="text-2.2">
<ul>
<li id="sec-2.2.1">Spot size at target < 50 μ m <br>
PRex adjust the spot size at target down to 50 μ m. The nominal
design value for 1 pass, 1 GeV beam is a bit larger than 100 μ m.
This requirement will need new optics that also respect the
requirements at the compton and other tight spots on the A line.
<p>Such a tight beam size will not be possible with combined
optics.
</p>
<p>
<span class="timestamp-wrapper"> <span class="timestamp">2009-12-21
Mon 13:06</span></span><br>
Jay has worked out an alternate optics, this optics needs to be
reviewed and evaluated before acceptance.
</p>
</li>
<li id="sec-2.2.2">Helicity Reversal <br>
Need to touch base with Hall-B, make sure they are ready for 240 Hz.
Any changes in helicity reversal during the run need to be coordinated
with Hall-B.
<ul>
<li id="sec-2.2.2.1"><span class="todo TODO"> TODO</span> Confirm
Hall-B 240Hz capable <span class="tag"><span class="Riad">Riad</span></span><br>
<span class="timestamp-wrapper"><span class="timestamp-kwd">DEADLINE:
</span> <span class="timestamp">2010-01-13 Wed</span></span><br>
</li>
</ul>
</li>
<li id="sec-2.2.3">Polarization Orientation <br>
At present the transverse component is nulled at the 2% level. To
achieve the desire 1% value will require effort. This effort is
mostly beam time, although it is not guaranteed that vertical
components at the 1% level can creep in as the beam traverses the
machine. To achieve better than 2% more dedicated time in the
injector will be required.
<p>PRex will ask for transverse measurements in the injector more
frequently than previous experiments. About once per week?
</p>
</li>
<li id="sec-2.2.4">Priority in source configuration <br>
Hall-B will, at times, like to control the Hall-B charge asymmetry.
They may not do this at the level that PRex would like…..
</li>
<li id="sec-2.2.5">Time for source configuration <br>
There is not much time for work on the source. The two wien system
must be installed and commissioned and commissioning higher voltage
gun operation is also scheduled. With such a tight schedule it is not
possible to have PRex staff perform laser alignment. The present plan
to have the source group configure the gun as best they can, including
laser alignment. Have PRex collaboration make measurements and if the
configuration is unacceptable, time will be made available to fix the
problems. </li>
<li id="sec-2.2.6">Control of the Source Lasers <br>
Aside from Hall-B IA control, this is not an issue
</li>
<li id="sec-2.2.7">Electron Beam Transmission <br>
This is not a spec. Yes we will configure the injector for minimal
transmission, but if parity quality and compton polarimetry functional
who cares what the transmission is.
</li>
<li id="sec-2.2.8">Helicity Correlated Beam Size <br>
Will need time to measure the laser spot size for the two different
helicity states. This issue drive the new desire for small beam size
at the target.
</li>
<li id="sec-2.2.9">Beam and halo acceptable for Compton Polarimeter <br>
The real specification here, is a compton polarimeter that achieves 1%
polarization error and beam that is acceptable for PRex
spectrometers. Previous changes to the Compton polarimeter and beam
tune issues have made the Fall run rather challenging. The compton
will be modified during the Winter down. Specific time for
commissioning the Compton and the beam needs to be a priority for the
commissioning period. </li>
<li id="sec-2.2.10">Fast feedback <br>
Stable optics near design will help make the fast feedback system
robust. This should be specifically addressed during the
commissioning period.
</li>
<li id="sec-2.2.11">Beam Modulation <br>
The PRex collaboration needs to communicate requirements and proposed
changes to the
software group as soon as possible if they want these changes ready
for the experiment.
</li>
<li id="sec-2.2.12">Phase Advance <br>
Two coil modulation will help achieve the desired phase advance.
</li>
<li id="sec-2.2.13">Random Beam Jitter at Target <br>
</li>
<li id="sec-2.2.14">Radiation levels <br>
The large beam current, modest energy and thick target will produce
quite a hot environment in the Hall. We need to be prepared to deal
with dieing IOCs.
<ul>
<li id="sec-2.2.14.1"><span class="todo TODO"> TODO</span>
Communicate High Rad levels in A to Controls and I&C <span
class="tag"><span class="Arne">Arne</span></span><br>
<span class="timestamp-wrapper"><span class="timestamp-kwd">DEADLINE:
</span> <span class="timestamp">2010-01-13 Wed</span></span><br>
Not sure what we can do. We have one VME bus extender ready (for
QWeak). Perhaps we should buy another. How many accelerator IOCs are
in the Hall?
</li>
</ul>
</li>
</ul>
</div>
</div>
<div id="outline-container-2.3" class="outline-3">
<h3 id="sec-2.3"><span class="section-number-3">2.3</span> Shutdown
Issues </h3>
<div class="outline-text-3" id="text-2.3">
<ul>
<li id="sec-2.3.1">Shim missing on 2T line <br>
<span class="timestamp-wrapper"> <span class="timestamp">2009-12-22
Tue 13:34</span></span><br>
Walk the line this morning did not see anything amiss. But did not
bring a flashlight, so I could have missed something.
</li>
<li id="sec-2.3.2">Droop in Injector <br>
Need to walk the injector chicane region to see if there is a visible
displacement of the beamline. </li>
</ul>
</div>
</div>
<div id="outline-container-2.4" class="outline-3">
<h3 id="sec-2.4"><span class="section-number-3">2.4</span> Next Year </h3>
<div class="outline-text-3" id="text-2.4">
<ul>
<li id="sec-2.4.1">Tiefenback!!!! <br>
</li>
<li id="sec-2.4.2">QWeak Beam requirements <span class="tag"><span
class="ATTACH">ATTACH</span></span><br>
QWeak has forwarded their beam requirements for us to review.
</li>
</ul>
</div>
</div>
</div>
<div id="postamble">
<p class="date"> Date: 2009-12-22 13:36:19 EST</p>
<p class="creator">HTML generated by org-mode 6.33trans in emacs 23</p>
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<pre class="moz-signature" cols="72">--
Arne Freyberger
Director Operations Department
Jefferson Lab Phone: (757) 269-6268
12000 Jefferson Avenue Pager: (757) 584-6268
Newport News, VA 23606 Email: <a class="moz-txt-link-abbreviated" href="mailto:freyberg@jlab.org">freyberg@jlab.org</a>
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