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Geoff,<br>
The limits in the 12GeV era are 1MW of beam power, so lower pass
experiments can request higher beam current. Specifically PREX is
lobbying to come back as a 1-pass experiment and will take as much
beam current as the target and the hall electronics can handle.<br>
Arne<br>
<br>
On 01/26/2012 11:39 AM, Geoffrey Krafft wrote:
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On 1/26/2012 9:27 AM, Matt Poelker wrote:
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During the long shutdown, John Hansknecht will try to implement
an idea that will allow us to produce longer laser pulses, which
as Mike T points out, could improve transmission, reduce
prebuncher gradient, and eliminate tails, etc.,. Unfortunately,
a longer laser pulse will not be available during QWeak and the
rest of the 6GeV run.<br>
Matt<br>
<br>
<br>
Todd Satogata wrote:
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<title>BTeam-2012-01-24</title>
Bteamers,<br>
<br>
Here are the notes from yesterday's weekly meeting. There was
a lot of discussion about the<br>
tune time on Thursday that attempted to install a new M56
optics in the injection chicane<br>
but eventually was removed. Some issues were found in the
model that will be addressed,<br>
a LEMI configuration problem was fixed, some optics anomalies
(such as the<br>
disappearing/reappearing blown dispersion mismatch out of arc
2) need understanding.<br>
We learned important things during that tune time, but we will
be more efficient if we<br>
have more time to plan and double-check for tuning; Yves's
summary at the end of what<br>
worked and what didn't will be helpful for the planning of the
5-pass spin-up; a plan is<br>
being developed that will be discussed and hopefully scheduled
by this week's beam<br>
studies scheduling meeting on Friday.<br>
<br>
Alex Bogacz has graciously agreed to chair the BTeam meeting
while I'm on travel<br>
to SLAC Jan 26-Feb 1 inclusive.<br>
<br>
-Todd<br>
<h1 class="title">BTeam-2012-01-24</h1>
<div class="outline-2">
<h2 id="sec-1">1 Optics on Call Report/Schedule</h2>
<ul>
<li>Rotates at BTeam (10:00 Tuesdays)<br>
</li>
<li>Medium-term machine development<br>
<ul>
<li><span class="done">DONE</span> Write 5-pass
spin-up ATLis (Jay, <a moz-do-not-send="true"
href="https://cebaf.jlab.org/atlis/task/11894">a11894</a>),
relies
on ARC9 box supply repair (ongoing)<br>
</li>
</ul>
</li>
<li>17 Jan-24 Jan: Vasily/Yves (Outgoing)<br>
<ul>
<li>SL has still been running few degrees off crest to
reduce Compton backgrounds (Jay)<br>
</li>
<li>Hall B sensitivity to energy drift of some concern
(Tief)<br>
</li>
<li>Mon 23 Jan Add M56 optics in injector (Yves/Jay, <a
moz-do-not-send="true"
href="https://cebaf.jlab.org/atlis/task/11924">a11924</a>)<br>
<ul>
<li>Not successful, see Yves's entry at <a
moz-do-not-send="true"
href="https://cebaf.jlab.org/elog/entry/1661381">e1661381</a><br>
</li>
<li>HGAP for inj chicane dipoles will be updated;
0L/0R optics plan in the works<br>
</li>
<li>12h of tuning time: what was gained? How are
we accountable for that time?<br>
<ul>
<li>Who owns the process of unscheduled
tuning? Optics or plan owner should be
focus; PD schedules time<br>
</li>
<li>Scheduling for studies <1h later makes
things rushed, perhaps hours of inefficiency<br>
</li>
<li>OptiM to elegant translation can use
better efficiency (at least yesterday)<br>
</li>
<li>High sensitivity of Compton halo to 1L02
quad was found at end in current
configuration<br>
</li>
<li>Now running 2.5 degrees off crest in SL,
better than the 6+ degrees over weekend<br>
</li>
<li>We're very likely on the edge of
something, including scraping, based on
large sensitivities<br>
</li>
<li>RayTrace would provide optics, may also
well provide an aperture check (Tief)<br>
</li>
<li>Spot was a lot tighter in 1A with the M56
improvement, so we will likely want to use
this in Feb<br>
</li>
<li>Is a longer laser pulse feasible for 180uA
for better injector transmission/Hall B?
(Tief)<br>
</li>
<li>Alex: Can redesign an M56 optics with a
stronger 1L02 quad setting for potentially
improved stability<br>
</li>
<li>Underlying cause of arc2 dispersion match
blown? Was seen in previous week as well
(Jay/Spata/Tief)<br>
</li>
<li><span class="done">DONE</span> Jay has
changed LEM config file for NL to set 1L02
quad to 521.6 (as of AM Jan 24 2012)<br>
</li>
<li><span class="todo">TODO</span> injector
rematch with HGAP in 0R dipoles
(Michele/Yves, report Feb 02 BTeam)<br>
</li>
<li><span class="todo">TODO</span> Address
blown arc2 dispersion match during Jan 25
beam studies recovery (Optics)<br>
</li>
<li><span class="todo">TODO</span> Planning
group for M56:
Yves/Jay/Tief/Alicia/Alex/Ed/Geoff/Yuhong<br>
</li>
</ul>
</li>
</ul>
</li>
</ul>
</li>
<li>24 Jan-31 Jan: Ed/Alex (Oncoming)<br>
<ul>
<li><span class="todo">TODO</span> Readdress injection
matching to NL, SL gang phase, Hall C Compton<br>
</li>
<li><span class="todo">TODO</span> Restore SL MOMOD
after SL on crest, confirm good Hall C Compton rates
(Tief/ops)<br>
</li>
<li><span class="todo">TODO</span> Diagnose
intermittent problems in NL MOMOD (Musson? Tief?
Plawski?)<br>
</li>
</ul>
</li>
<li>31 Jan-07 Feb: Yuhong/Geoff<br>
<ul>
<li>5-pass spin-up schedule? Mid-February for Hall A,
but early Feb for Hall B shift?<br>
</li>
</ul>
</li>
<li>07 Feb-14 Feb: Balsa/Todd<br>
</li>
<li>14 Feb-21 Feb: Fanglei/Mike Spata<br>
</li>
<li>21 Feb-28 Feb: Todd/Jay<br>
</li>
</ul>
</div>
<div class="outline-2">
<h2 id="sec-2">2 Measuring Bunch Length using 1A Sync Light
Monitor (Tief)</h2>
<ul>
<li>New BTeam elog entry on this procedure: <a
moz-do-not-send="true"
href="https://cebaf.jlab.org/elog/entry/1661304">e1661304</a><br>
</li>
<li>Done capturing images from datacube; online bunch
length application may be resurrected (Michele/Tief)<br>
</li>
<li>Arne believes this will be resurrected when we have
pure digital cameras for 12 GeV<br>
</li>
<li><span class="todo">TODO</span> Prioritize and
projectize for long down (Arne)<br>
</li>
</ul>
</div>
<div class="outline-2">
<h2 id="sec-3">3 C100 Status</h2>
<ul>
<li>26/52/79 Hz signal on 1/4 cryo drive gradient/phase
(Suleiman/Spata)<br>
</li>
<li>Beam studies rescheduled for Wed 25 Feb<br>
</li>
</ul>
</div>
<div class="outline-2">
<h2 id="sec-4">4 Beam Studies Report 18 Jan 2012</h2>
<ul>
<li>Studies scheduled 08:00-20:00 (on time)<br>
<ul>
<li> <a moz-do-not-send="true"
href="https://cebaf.jlab.org/atlis/task/11858">a11858</a>
0.0 C100: Search for 79 Hz (Parisitic,
Suleiman/Spata; strong 52 Hz on 1/4 cryo drive
gradient/phase) </li>
<li> No other studies accomplished due to box supply
failures, repair </li>
</ul>
</li>
</ul>
</div>
<div class="outline-2">
<h2 id="sec-5">5 Beam Studies Scheduled 25 Jan 2012</h2>
<ul>
<li><span class="todo">TODO</span> Submit ATLis items for
desired beam studies for next week (25 Jan)<br>
</li>
<li>Same studies as last week based on lost time to box
supply failures<br>
</li>
<li>Studies scheduled 08:30-20:30<br>
<ul>
<li> <b>[<span style="visibility: hidden;">X</span>]</b>
—— 1.0 Optics: Fopts/allsaves </li>
<li> <b>[<span style="visibility: hidden;">X</span>]</b>
<a moz-do-not-send="true"
href="https://cebaf.jlab.org/atlis/task/11882">a11882</a>
8.0 C100: Stability testing (Hovater, Spata, etc,
full gradient on both C100s, 10uA) </li>
<li> <b>[<span style="visibility: hidden;">X</span>]</b>
<a moz-do-not-send="true"
href="https://cebaf.jlab.org/atlis/task/11865">a11865</a>
1.0 Modeling: RayTrace validation (Bodenstein, Tief)
</li>
<li> <b>[<span style="visibility: hidden;">X</span>]</b>
<a moz-do-not-send="true"
href="https://cebaf.jlab.org/atlis/task/11885">a11885</a>
0.0 PePPo: Modeling (Grames, Contingency) </li>
<li> <b>[<span style="visibility: hidden;">X</span>]</b>
<a moz-do-not-send="true"
href="https://cebaf.jlab.org/atlis/task/11849">a11849</a>
0.0 Mott: Mott DAQ Test (Suleiman, Contingency) </li>
<li> <b>[<span style="visibility: hidden;">X</span>]</b>
—— 2.0 Optics: Restoration </li>
</ul>
</li>
<li><span class="todo">TODO</span> Optics should write
notes, observations of fopt/etc to Bteam elog<br>
<ul>
<li>Include pathlength check (pathlength was good Mon
day)<br>
</li>
</ul>
</li>
</ul>
</div>
<div class="outline-2">
<h2 id="sec-6">6 Next week</h2>
<ul>
<li>Alex Bogacz has graciously agreed to chair while Todd
is on travel<br>
</li>
<li>Hall B to 5th pass ~ Feb 1?<br>
</li>
</ul>
</div>
<div class="outline-2">
<h2 id="sec-7">7 From last week: Evaluate possibilities of
Krest during beam restoration (Okay)</h2>
<ul>
<li>Takes more like 4h to run through both linacs to get
decent results (Terry)<br>
</li>
<li>But Hall C doesn't get good data while Krest is
running either (but Hall B can)<br>
</li>
<li>Perhaps part of 2h can be a manual touch-up of
cresting (15 min total, 2 operators)<br>
<ul>
<li><span class="todo">TODO</span> Todd has emailed
Noel to see if manual touch-up is acceptable weekly
retune</li>
</ul>
</li>
</ul>
</div>
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_______________________________________________
Bteam mailing list
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</blockquote>
<br>
<br>
<pre class="moz-signature" cols="72">--
Matt Poelker
Jefferson Lab
MS Bldg 5A, Rm 500-17
12000 Jefferson Ave.,
Newport News, VA 23606
<a moz-do-not-send="true" class="moz-txt-link-abbreviated" href="mailto:poelker@jlab.org">poelker@jlab.org</a>
757-269-7357 office
757-897-9408 cell
</pre>
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_______________________________________________
Bteam mailing list
<a moz-do-not-send="true" class="moz-txt-link-abbreviated" href="mailto:Bteam@jlab.org">Bteam@jlab.org</a>
<a moz-do-not-send="true" class="moz-txt-link-freetext" href="https://mailman.jlab.org/mailman/listinfo/bteam">https://mailman.jlab.org/mailman/listinfo/bteam</a></pre>
</blockquote>
Not that I want to stop progress, but I would point out that<br>
we are not scheduled to do any 180 muA running to any hall<br>
AFTER the shutdown, and even if we were, my calculations<br>
show that at 500 MHz and 180 muA, the beam charge is<br>
0.36 pC. If some form of "space charge" mechanism is being<br>
invoked that might "get better" with less charge density, I would<br>
need to see a calculation using, e.g., a formula from Rieser to<br>
convince me that <br>
<br>
What IS certain is that the larger bunch length will introduce<br>
greater curvature effects in the compression and aberations.<br>
Not a clear improvement to me!<br>
<br>
Geoff<br>
<br>
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<br>
<pre wrap="">_______________________________________________
Bteam mailing list
<a class="moz-txt-link-abbreviated" href="mailto:Bteam@jlab.org">Bteam@jlab.org</a>
<a class="moz-txt-link-freetext" href="https://mailman.jlab.org/mailman/listinfo/bteam">https://mailman.jlab.org/mailman/listinfo/bteam</a></pre>
</blockquote>
<br>
<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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