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Regarding the bunch compression, it is larger than we usually run with. However, the design for maximum compression calls for up to 10.8 degrees. In practice, since the bunch is not necessarily upright, we rarely end up with this. Another limitation we had
in the past is that excessive bunch compression offset ends up producing losses in the chicane itself due to the large energy spread it generates. I am actually surprised we can push 150 this way. Last time, above 4 degrees it was problematic. </div>
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This being said, if Hall A is taking productive data and we are not trashing the machine in this configuration, I would probably suggest we wait until the 8/31 pass change to address this as it will likely require adjusting other parameters to keep Hall A Compton
rate low (steering, matching).</div>
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We can discuss that tomorrow at the BTeam.</div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>From:</b> BTeam <bteam-bounces@jlab.org> on behalf of Mike Spata <spata@jlab.org><br>
<b>Sent:</b> Monday, August 24, 2020 10:01 AM<br>
<b>To:</b> Brian Freeman <bfreeman@jlab.org>; bteam@jlab.org <bteam@jlab.org>; Michael Aiken <aiken@jlab.org>; HyeKyoung Park <hkpark@jlab.org>; Paul Vasilauskis <vasilaus@jlab.org>; ciprian@jlab.org <ciprian@jlab.org>; Daniel Moser <moser@jlab.org>; Eric Forman
<eforman@jlab.org><br>
<b>Subject:</b> Re: [BTeam] Hall A Energy discussion</font>
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Good morning,</div>
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The last <a href="https://logbooks.jlab.org/files/2020/08/3830068/2008744.1.png" title="https://logbooks.jlab.org/files/2020/08/3830068/2008744.1.png">
image</a> of the Lambertson that was logged had Hall A beam left of center. It may have been adjusted already and not logged. Hard to say if it's too far left of center since we can't see the wires anymore but might be worth taking a look. The comment was made
this morning regarding the Hall B beam so if you are looking I would line them up as best you can.</div>
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I agree that the bunch compression is too large (>10 degrees from Eric's log) and we should not have to run like this for good transport. Definitely a topic for B-Team.</div>
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Mike</div>
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<div id="x_divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>From:</b> BTeam <bteam-bounces@jlab.org> on behalf of Brian Freeman <bfreeman@jlab.org><br>
<b>Sent:</b> Monday, August 24, 2020 8:21 AM<br>
<b>To:</b> bteam@jlab.org <bteam@jlab.org>; Michael Aiken <aiken@jlab.org>; HyeKyoung Park <hkpark@jlab.org>; Paul Vasilauskis <vasilaus@jlab.org>; ciprian@jlab.org <ciprian@jlab.org>; Daniel Moser <moser@jlab.org>; Eric Forman <eforman@jlab.org><br>
<b>Subject:</b> Re: [BTeam] Hall A Energy discussion</font>
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Just some clarification about the Hall A energy discussion of this morning.</div>
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<li>Hall A is requesting a certain energy error (dp/p) -1E-4. This is an abnormal request.</li><li>With FFB on in Energy mode, or when running Arc 2 it does as designed and brings the error even closer to zero down to the E-5 range. So not sure what this request is about, and I believe this abnormal request is the root of the Hall A issue. (Cipran ?) </li><li>This issue with monitoring the SLMs, is that we are running 0L04 so far off crest that the spots almost encompass the entire image frame:</li><ol style="list-style:lower-alpha">
<li><a href="https://logbooks.jlab.org/entry/3832990" id="LPlnk812299">https://logbooks.jlab.org/entry/3832990</a><br>
</li><li>This was done to reduce Compton rates. </li><li>I suggest we back out of the 0L04 change. </li></ol>
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<div>BTeam items for tomorrow's meeting? Yves you still on vacation? </div>
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<div>Any others chime in, please.</div>
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<div>-Brian</div>
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