<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Hi All,<div class=""><br class=""></div><div class=""> Today turned out to not be a great day for most people to meet. It ended up being</div><div class="">just Ilya and I. We did have a discussion on what we would like to do with the chamber</div><div class="">and any remaining beam opportunity. Here are the ideas we came up with so others</div><div class="">may comment:</div><div class=""><br class=""></div><div class="">1. Change the gas mixture to 90/10. We have not yet spoken with Tom/Scot on how</div><div class="">difficult this is. We will do that this week.</div><div class=""><br class=""></div><div class="">2. Change the scintillator paddle position to be closer to the beam line.</div><div class=""><br class=""></div><div class="">3. Machine a hole in the 10.75” steel plate and center it on the beam line. This will</div><div class="">give a much closer approximation of beam conditions. The hole should be round with</div><div class="">a diameter between 6.6cm and 8cm. According to my notes, the dead region in this</div><div class="">chamber is 3.4” in diameter (=8.64 cm). Studies from last year set the beam hole</div><div class="">size to 2cm smaller in diameter compared to the dead region so if we follow that,</div><div class="">the hole size should be ~6.6 cm. The final design parameter for the dead region from</div><div class="">those same studies was 10 cm with a beam hole of 8cm diameter. </div><div class=""><br class=""></div><div class="">One option is to try and do both by cutting the smaller hole, taking data, and then cutting</div><div class="">the larger hole. Alternatively, we could cut the larger hole and then make a plug or mask</div><div class="">to get data with the smaller hole size.</div><div class=""> </div><div class=""><div class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">The chamber is currently out of the beam. There may be opportunity on Monday to </div><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">reinstall it along with any of these modifications. There is also a possibility they will</div><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">extend the run for one more week.</div></div></div><div class=""><br class=""></div><div class="">Rory and Elton: please think about this and let us know what you think and if there are</div><div class="">any other things you would like to do during the remainder of this run period.</div><div class=""><br class=""></div><div class=""><div class=""><div style="color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Regards,</div><div style="color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">-David</div><div style="color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><font color="#6a6a6a" class=""><br class=""></font></div><div style="color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><font color="#6a6a6a" class="">-------------------------------------------------------------</font></div><div style="color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><font color="#6a6a6a" class="">David Lawrence Ph.D.</font></div><div style="color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><font color="#6a6a6a" class="">Staff Scientist, Thomas Jefferson National Accelerator Facility<br class="">Newport News, VA</font></div><div style="color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><font color="#6a6a6a" class=""><a href="mailto:davidl@jlab.org" class="">davidl@jlab.org</a><br class="">(757) 269-5567 W<br class="">(757) 746-6697 C</font><br class=""><br class=""></div>
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