<html><body><div style="font-family: arial, helvetica, sans-serif; font-size: 12pt; color: #000000"><div><br></div><div> Dear Colleagues, <br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div> A message from Doug. <br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div> Best regards, Eric<br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><hr id="zwchr" data-marker="__DIVIDER__"><div data-marker="__HEADERS__"><b>De: </b>"Douglas Higinbotham" <doug@jlab.org><br><b>À: </b>"Eric Voutier" <voutier@ijclab.in2p3.fr><br><b>Envoyé: </b>Jeudi 11 Mai 2023 02:46:54<br><b>Objet: </b>Positron Memo sent to PAC51: message from Douglas Higinbotham<br></div><div><br><style><!--
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<p class="MsoNormal"><span style="font-size:12pt"> </span></p>
<p class="MsoNormal"><span style="font-size:12pt">Dear Positron Working Group,</span></p>
<p class="MsoNormal"><span style="font-size:12pt"> </span></p>
<p class="MsoNormal"><span style="font-size:12pt">In order to help the program advisory committee understand the parameters of the proposed 12GeV positron beam at Jefferson Lab, the following letter was drafted:</span></p>
<p class="MsoNormal"><a href="https://www.jlab.org/sites/default/files/PAC/PAC51/Positron-Statement-wiht-Hyperlinks.pdf" target="_blank" rel="nofollow noopener noreferrer"><span style="font-size:12pt">https://www.jlab.org/sites/default/files/PAC/PAC51/Positron-Statement-wiht-Hyperlinks.pdf</span></a><span style="font-size:12pt">.
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<p class="MsoNormal"><span style="font-size:12pt">This document was written by Joe Grames, Douglas Higinbotham, Eric Voutier, and Xiaochao Zheng; reviewed by physics AD Thia Keppel; and submitted by Thia to the PAC chair. The goal of this letter was to provide
reasonable starting parameters for physics proposal. </span></p>
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<p class="MsoNormal"><span style="font-size:12pt">While experiments can be submitted with parameters that exceed these baseline parameters, they shouldn’t be expecting to be a first generation JLab positron experiment. As an explicate example, the >1 uA
unpolarized beam listed in the table simply means that one can reasonably expect to get 1 uA of beam and unpolarized positron experiments wishing to get fully approved at PAC51 should calculate their PAC days accordingly.
</span></p>
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<p class="MsoNormal"><span style="font-size:12pt">Sincerely,</span></p>
<p class="MsoNormal"><span style="font-size:12pt">Douglas</span></p>
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