<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body dir="auto">
My quick reaction, interspersed below in <font color="#e22400">‘RED’</font>
<div><br>
</div>
<div>Cheers,<br>
<br>
<div dir="ltr">
<div>
<p class="MsoNormal" style="margin: 0cm 0cm 0.0001pt;"><span style="background-color: rgba(255, 255, 255, 0);">Alex<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal" style="margin: 0cm 0cm 0.0001pt;"><span style="background-color: rgba(255, 255, 255, 0);">___________________________________<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal" style="margin: 0cm 0cm 0.0001pt;"><span style="background-color: rgba(255, 255, 255, 0);">S. Alex Bogacz,<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal" style="margin: 0cm 0cm 0.0001pt;"><span style="background-color: rgba(255, 255, 255, 0);">Accelerator Physics Group Leader<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal" style="margin: 0cm 0cm 0.0001pt;"><span style="background-color: rgba(255, 255, 255, 0);">Center for Advanced Studies of Accelerators<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal" style="margin: 0cm 0cm 0.0001pt;"><span style="background-color: rgba(255, 255, 255, 0);">Jefferson Lab<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal" style="margin: 0cm 0cm 0.0001pt;"><font color="#000000"><span style="caret-color: rgb(0, 0, 0); background-color: rgba(255, 255, 255, 0);"><a href="x-apple-data-detectors://8" dir="ltr" x-apple-data-detectors="true" x-apple-data-detectors-type="address" x-apple-data-detectors-result="8" style="text-decoration-color: rgba(127, 127, 127, 0.380392);">12000
Jefferson Avenue,</a><o:p></o:p></span></font></p>
</div>
<div>
<p class="MsoNormal" style="margin: 0cm 0cm 0.0001pt;"><font color="#000000"><span style="caret-color: rgb(0, 0, 0); background-color: rgba(255, 255, 255, 0);"><a href="x-apple-data-detectors://8" dir="ltr" x-apple-data-detectors="true" x-apple-data-detectors-type="address" x-apple-data-detectors-result="8" style="text-decoration-color: rgba(127, 127, 127, 0.380392);">Newport
News, VA 23606</a><o:p></o:p></span></font></p>
</div>
<span style="background-color: rgba(255, 255, 255, 0);">___________________________________</span>
<div>Sent from my iPhone</div>
</div>
<div dir="ltr"><br>
<blockquote type="cite">On Jun 30, 2022, at 3:37 PM, Brooks, Stephen <sbrooks@bnl.gov> wrote:<br>
<br>
</blockquote>
</div>
<blockquote type="cite">
<div dir="ltr"><span>Continuing to think about the design constraints, of my five, these two can be optimised by the lattice people:</span><br>
<span></span><br>
<span>- How many full turns in total? (9/10/11)</span><br>
</div>
</blockquote>
<font color="#e22400">11</font><br>
<blockquote type="cite">
<div dir="ltr"><span>- Make the East and West FFAs different? (answer likely yes)</span><br>
</div>
</blockquote>
<font color="#e22400">Y</font><br>
<blockquote type="cite">
<div dir="ltr"><span></span><br>
<span>But these three require answers from JLAB:</span><br>
<span></span><br>
<span>- 1090MeV linac or 1200MeV?</span><br>
</div>
</blockquote>
<font color="#e22400">1090 MeV</font><br>
<blockquote type="cite">
<div dir="ltr"><span>- How many EM passes before the first FFA? (3/4/5)</span><br>
</div>
</blockquote>
<font color="#e22400">4</font><br>
<blockquote type="cite">
<div dir="ltr"><span>(This one is related to the availability of a 6th beamline "shelf" in the arcs)</span><br>
</div>
</blockquote>
<font color="#e22400">If we decide to use two FFAs, say 4 +3, as a staged approach the second FFA could go into the ‘6th beamline shelf’</font><br>
<blockquote type="cite">
<div dir="ltr"><span>- Tunable energy range and if so how much? (0-15%)</span><br>
</div>
</blockquote>
<font color="#e22400">10-15%</font><br>
<blockquote type="cite">
<div dir="ltr"><span></span><br>
<span>Think of it like: a single FFA will give you ~19GeV but each of these three concessions (linac upgrade, 6th shelf, no tunability) gives you very roughly +2GeV in energy.</span><br>
<span></span><br>
<span>Then JLAB have to decide how much energy they want vs. these concessions.</span><br>
<span></span><br>
<span>NB: Dejan assumed no tunability, or perhaps tunability but only upwards in the linac energy (so assuming the linac upgrade instead!)</span><br>
<span></span><br>
<span> -Stephen</span><br>
<span></span><br>
<span>________________________________________</span><br>
<span>From: FFA_CEBAF_Collab <ffa_cebaf_collab-bounces@jlab.org> on behalf of Brooks, Stephen via FFA_CEBAF_Collab <ffa_cebaf_collab@jlab.org></span><br>
<span>Sent: 24 June 2022 15:25</span><br>
<span>To: Ryan Bodenstein; Alex Bogacz; Trbojevic, Dejan</span><br>
<span>Cc: ffa_cebaf_collab@jlab.org; Douglas Higinbotham</span><br>
<span>Subject: Re: [FFA_CEBAF_Collab] [EXTERNAL] Re: FFA@CEBAF WG mtg. this Friday, June 24 at 11:00 am</span><br>
<span></span><br>
<span>Quick reminder of constraint choices determining the CEBAF FFA arcs:</span><br>
<span></span><br>
<span>- 1090MeV linac or 1200MeV?</span><br>
<span>- How many EM passes before the first FFA? (3/4/5)</span><br>
<span>- How many full turns in total? (9/10/11)</span><br>
<span>- Tunable energy range and if so how much? (0-15%)</span><br>
<span>- Make the East and West FFAs different?</span><br>
<span></span><br>
<span>Of these, 1200MeV linac, more EM passes, fewer full turns (i.e. lower output energy), no tunability and making the East/West different - all make the FFAs *easier* (higher field magnets). The opposite choices make the FFAs harder.</span><br>
<span></span><br>
<span>For my 2021 design, reported in IPAC'22 recently, I made the following choices:</span><br>
<span>- 1090MeV linac</span><br>
<span>- 3 EM passes</span><br>
<span>- 11 full turns</span><br>
<span>- Full tunability</span><br>
<span>- East and West FFAs identical.</span><br>
<span></span><br>
<span>These all make the FFAs harder! In the case of the fifth one, there's no reason to do this other than me not wanting to double the number of lattices I had to build. So basically my design is conservative at the same time as trying to get the maximum
functionality and not needing the 6th "shelf". But could be improved slightly by separate optimisation of East and West.</span><br>
<span></span><br>
<span>If you relax the constraints, you can do better.</span><br>
<span></span><br>
<span>EM passes is interesting:</span><br>
<span>3 = can upgrade to two FFAs without 6th shelf, but lower performance</span><br>
<span>4 = can get first FFA without 6th shelf but need it for the second FFA</span><br>
<span>5 = can only do one FFA, second FFA would require removal of an EM line</span><br>
<span></span><br>
<span>So to me selecting 4 seems quite good here if there's any real chance of using the 6th shelf in the future.</span><br>
<span></span><br>
<span>Number of full turns determines the output energy:</span><br>
<span>9 = 19.x GeV or 21.x GeV with the 1200MeV linac</span><br>
<span>10 = 21.x GeV or 23.x GeV with the 1200MeV linac</span><br>
<span>11 = 23.x GeV or 25.x GeV with the 1200MeV linac</span><br>
<span></span><br>
<span>My old single-FFA solution that required difficult 2.0T magnets was 4+7=11 turn design. However, it looks like a less ambitious 4+5=9 turns would have much easier magnets. Dejan was showing 5+5 today. And a small bump in linac energy would have got
us above 20GeV again, if that's enough.</span><br>
<span></span><br>
<span>Instead of 3+4+4, 3+5+3=11 schemes for a dual-FFA design, it's interesting to think about, say, 4+4+3 (still 11 turns but uses the 6th shelf in the dual-FFA upgrade). Next week I might look for lattices for this.</span><br>
<span></span><br>
<span> -Stephen</span><br>
<span></span><br>
<span>________________________________________</span><br>
<span>From: FFA_CEBAF_Collab <ffa_cebaf_collab-bounces@jlab.org> on behalf of Trbojevic, Dejan via FFA_CEBAF_Collab <ffa_cebaf_collab@jlab.org></span><br>
<span>Sent: 24 June 2022 13:45</span><br>
<span>To: Ryan Bodenstein; Alex Bogacz</span><br>
<span>Cc: ffa_cebaf_collab@jlab.org; Douglas Higinbotham</span><br>
<span>Subject: [FFA_CEBAF_Collab] [EXTERNAL] Re: FFA@CEBAF WG mtg. this Friday, June 24 at 11:00 am</span><br>
<span></span><br>
<span>Dear All,</span><br>
<span></span><br>
<span>I uploaded the files in Bmad with instructions how to run it. I did not write details of the ‘tao’ commands like ‘show lattice’, ‘view 3’ (show the results from the universe 3 or energy 3, ‘show element’ and so on as you can find these instructions in
the tao Manual or Bmad Manual on the WEB. I also uploaded the EXCELL files where I calculated the synchrotron radiation losses.</span><br>
<span></span><br>
<span>Have fun,</span><br>
<span></span><br>
<span>Best from,</span><br>
<span></span><br>
<span>Dejan</span><br>
<span></span><br>
<span>From: FFA_CEBAF_Collab <ffa_cebaf_collab-bounces@jlab.org> on behalf of Ryan Bodenstein via FFA_CEBAF_Collab <ffa_cebaf_collab@jlab.org></span><br>
<span>Date: Friday, June 24, 2022 at 12:10 PM</span><br>
<span>To: Alex Bogacz <bogacz@jlab.org></span><br>
<span>Cc: ffa_cebaf_collab@jlab.org <ffa_cebaf_collab@jlab.org>, Douglas Higinbotham <doug@jlab.org></span><br>
<span>Subject: Re: [FFA_CEBAF_Collab] FFA@CEBAF WG mtg. this Friday, June 24 at 11:00 am</span><br>
<span>Hello colleagues!</span><br>
<span></span><br>
<span>Thanks for an exciting meeting. I think we can all look forward to what will grow out of this exchange. You’ll find the minutes attached to this email, as well as uploaded to the shared folder.</span><br>
<span></span><br>
<span>Have a great weekend, and we’ll talk again next week.</span><br>
<span></span><br>
<span>Cheers!</span><br>
<span>Ryan</span><br>
<span></span><br>
<span>From: FFA_CEBAF_Collab <ffa_cebaf_collab-bounces@jlab.org> on behalf of Alex Bogacz via FFA_CEBAF_Collab <ffa_cebaf_collab@jlab.org></span><br>
<span>Date: Monday, June 20, 2022 at 6:30 PM</span><br>
<span>To: Alex Bogacz <bogacz@jlab.org></span><br>
<span>Cc: ffa_cebaf_collab@jlab.org <ffa_cebaf_collab@jlab.org></span><br>
<span>Subject: [FFA_CEBAF_Collab] FFA@CEBAF WG mtg. this Friday, June 24 at 11:00 am</span><br>
<span></span><br>
<span>Dear Colleagues,</span><br>
<span>We will resume our design efforts on Friday, June 24 at 11:00 am.</span><br>
<span>* Synchrotron Radiation calculation – Dejan</span><br>
<span>* IPAC’22 impressions – Stephen and Ryan</span><br>
<span>* AOB – All</span><br>
<span>Please, follow a ZOOM invitation below.</span><br>
<span>Cheers,</span><br>
<span>Alex</span><br>
<span>___________________________________</span><br>
<span>S. Alex Bogacz,</span><br>
<span>Accelerator Physics Group Leader</span><br>
<span>Center for Advanced Studies of Accelerators</span><br>
<span>Jefferson Lab</span><br>
<span>12000 Jefferson Avenue,<x-apple-data-detectors://8></span><br>
<span></span><br>
<span></span><br>
<span>ZOOM connection:</span><br>
<span></span><br>
<span>The link is here: https://urldefense.proofpoint.com/v2/url?u=https-3A__jlab-2Dorg.zoomgov.com_j_1614898082-3Fpwd-3DTnUzMS81M2sxbDZIbERJU01tYkJCQT09&d=DwIF-g&c=CJqEzB1piLOyyvZjb8YUQw&r=Ogg4WFNBwvADBq3fkmCLiJ7SaRDPYtawHzJElJMB0jE&m=YEQH-1vPGY0_hwTB5a-8w6fOLWDsAaIPdI2OXpr_3ZH1lXIxJAcdUocoG0kKt1Oh&s=BKquMzuFC3XNQ2S-fR0nmGhkJaGxiEs3-D9RjcoAQ-0&e=
<https://urldefense.com/v3/__https:/jlab-org.zoomgov.com/j/1614898082?pwd=TnUzMS81M2sxbDZIbERJU01tYkJCQT09__;!!P4SdNyxKAPE!F8uSrkdBjdVx0vjaMTaSIbqECTVvXKb_NE2LkbEQcgJZJXv81hD8jTCHBvIvRE5fqjZILa6X-IAjIJRRaq-us4i9EwFY$></span><br>
<span></span><br>
<span>In case of problems, the zoom room is below:</span><br>
<span>Meeting ID: 161 489 8082</span><br>
<span>Passcode: 123456</span><br>
<span></span><br>
<span></span><br>
<span>_______________________________________________</span><br>
<span>FFA_CEBAF_Collab mailing list</span><br>
<span>FFA_CEBAF_Collab@jlab.org</span><br>
<span>https://mailman.jlab.org/mailman/listinfo/ffa_cebaf_collab</span><br>
<span></span><br>
<span>_______________________________________________</span><br>
<span>FFA_CEBAF_Collab mailing list</span><br>
<span>FFA_CEBAF_Collab@jlab.org</span><br>
<span>https://mailman.jlab.org/mailman/listinfo/ffa_cebaf_collab</span><br>
</div>
</blockquote>
</div>
</body>
</html>