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Hi Brad,</div>
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The bypass of flat slabs coils were planned for GMn/GEn due to stray field on<span style="color: rgb(0, 0, 0); font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt;"> BB detectors. </span><span style="color: rgb(0, 0, 0); font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt;">The
plan now is to use 2100 A <span style="margin:0px;font-size:12pt;caret-color:rgb(0, 0, 0);background-color:rgb(255, 255, 255)">
<span style="margin:0px">with </span></span><span style="margin:0px;font-size:12pt;caret-color:rgb(0, 0, 0);background-color:rgb(255, 255, 255)">4 flat slabs as now considered</span>, when needed, which provides 1.60 Tm.</span></div>
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Bogdan</div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Brad Sawatzky <brads@jlab.org><br>
<b>Sent:</b> Friday, October 29, 2021 3:57 PM<br>
<b>To:</b> Robin Wines <wines@jlab.org>; Jessie Butler <jbutler@jlab.org>; Bogdan Wojtsekhowski <bogdanw@jlab.org>; Andrew Puckett <puckett@jlab.org>; Arun Tadepalli <arunts@jlab.org>; David Hamilton <dhamilto@jlab.org>; Michael Kohl <kohlm@jlab.org><br>
<b>Cc:</b> sbs@jlab.org <sbs@jlab.org><br>
<b>Subject:</b> [EXTERNAL] Physics impact of modifications to the SBS magnet on upcoming program?</font>
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<div class="PlainText">Hi folks,<br>
<br>
I thought about asking these during today's RC meeting, but decided<br>
it might be easier to get better answers on the list.<br>
<br>
I gather 6 of 10 of the SBS racetrack coils will be bypassed and, at<br>
least in the near term, the magnet will be run at a lower current.<br>
<br>
How does this impact the field uniformity (within the acceptance)<br>
and the integrated BdL of SBS? Is the lower SBS current (1600A?)<br>
intended to be a maximum for this run period (I wasn't sure how to<br>
interpret that discussion).<br>
<br>
I believe GEn-RP assumed a BdL of 1.7 T.m at a nominal 2000A. It<br>
would be good to know well in advance if those assumptions need to<br>
be reworked.<br>
<br>
<br>
Other important mechanical/engineering items that need to be reviewed<br>
with Jessie and Robin (et al.) include:<br>
<br>
- Status and plans for the beamline shielding 'wall' that sits between<br>
SBS and the beamline and will need to be installed along with the<br>
GEn-RP detectors.<br>
<br>
- Installation and possible mechanical interferences with the SBS<br>
Rear Field Clamp.<br>
- This is not presently installed but will need to be installed with<br>
the GEn-RP detectors.<br>
- As it stands the new braces between SBS and the beamline corrector<br>
magnets appear incompatible with the SBS rear field clamp.<br>
<br>
- Magnetic forces on the (steel) passive analyzer plate.<br>
- I know this has been raised several times in the past, but given the<br>
recent excitement those calculations should probably be reviewed.<br>
<br>
-- Brad<br>
<br>
-- <br>
Brad Sawatzky (he/him), PhD <brads@jlab.org> -<>- Jefferson Lab/ Hall C/C111<br>
Ph: 757-269-5947 -<>- Fax: 757-269-5235 -<>- Pager: brads-page@jlab.org<br>
The most exciting phrase to hear in science, the one that heralds new<br>
discoveries, is not "Eureka!" but "That's funny..." -- Isaac Asimov<br>
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