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If "as much beam as possible" is greater than the present
administrative limits of beam intercepting components (cups, dumps)
then maybe these should be included on an accelerator punch list of
items that the TAC committee would hopefully include.<br>
<br>
On 01/26/2012 11:42 AM, Arne Freyberger wrote:
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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:
<blockquote cite="mid:4F2181C1.6000406@jlab.org" type="cite">
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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:
<blockquote cite="mid4F202145.4060209@jlab.org" type="cite">
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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>
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</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 moz-do-not-send="true" class="moz-txt-link-abbreviated" href="mailto:freyberg@jlab.org">freyberg@jlab.org</a>
</pre>
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