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We are planning on replacing the RF module at 1A21 and 1A26 during the maintenance day tomorrow. If the North Linac was open we could change the RF module at 1A04 as well. The A04 stack has been very problematic and we cannot guarantee that replacing the
RF module would fix it. However, it would give us some valuable data and there is a chance it will fix the issue.<br>
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--Nate<br>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Jay Benesch <benesch@jlab.org><br>
<b>Sent:</b> Tuesday, November 28, 2023 10:29 AM<br>
<b>To:</b> BTeam <bteam@jlab.org>; Christopher Slominski <cjs@jlab.org>; Adam Carpenter <adamc@jlab.org>; Nathan Rider <nrider@jlab.org>; Dave Gaskell <gaskelld@jlab.org><br>
<b>Subject:</b> NL gradient calibration results</font>
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<div class="PlainText">Colleagues,<br>
<br>
The spreadsheet attached has the results of the rfcal run taken of the <br>
entire NL in order over ten hours with 1E-3 energy lock offset and <br>
comparison with data taken with somewhat different conditions earlier <br>
that day and the previous day - see comments column.<br>
<br>
The 11/16 data beginning 1545 was taken with<br>
IPM1A04 2.51 m etax<br>
IPM1A21 7.59 m etax<br>
IPM1A26 -2.39 m etax<br>
either disabled or excluded from BEM<br>
<br>
The earlier data was taken with IPM1A26 included.<br>
<br>
All of the SL data was taken with all BPMs active. The sum of the <br>
calibrated momentum gains was 1037.3 MeV vs 1047 MeV per the arc.<br>
<br>
In the NL, without these three BPMs, the sum is 1180 MeV, 12.7% above <br>
1047. I conclude that BEM's calculation and therefore the energy lock <br>
is not accurate without at least 1A21 and perhaps all three BPMs. This <br>
may explain why the polarization has been off expected values in all <br>
halls and why HALLC:p is 20 MeV below that expected from eDT.<br>
<br>
Jay<br>
<br>
<br>
<br>
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