<html><body><div style="font-family: arial,helvetica,sans-serif; font-size: 12pt; color: #000000"><div>Yes, off the diameter. It would leave a 200um gap at top.<br></div><div><br data-mce-bogus="1"></div><div>We can overcome this by making 2 custom pieces, so not a big deal.<br data-mce-bogus="1"></div><div><br></div><div><br></div><div data-marker="__SIG_PRE__">Tim Whitlatch<br>Hall D Engineer<br>Jefferson Lab<br>600 KELVIN DR STE 5<br>Newport News, VA 23606-4468 <br>757-269-5087</div><div><br></div><hr id="zwchr" data-marker="__DIVIDER__"><div data-marker="__HEADERS__"><b>From: </b>"Curtis A. Meyer" <cmeyer@cmu.edu><br><b>To: </b>"Richard Jones" <richard.t.jones@uconn.edu><br><b>Cc: </b>"Timothy Whitlatch" <whitey@jlab.org>, "Hall-D Tagged Beam Group" <halld-tagger@jlab.org>, "Egiyan, Hovanes" <hovanes@jlab.org><br><b>Sent: </b>Thursday, January 21, 2016 12:25:56 PM<br><b>Subject: </b>Re: [Halld-tagger] Tungsten tube in primary collimator<br></div><div><br></div><div data-marker="__QUOTED_TEXT__">I think it comes of a diamater, not the length. That leaves a small “crack” along the top??<br class=""><div class="">
<span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; " class=""><div class="">-------</div><div class="">Prof. Curtis A. Meyer<span class="Apple-tab-span" style="white-space: pre; "> </span> <span class="Apple-converted-space"> </span>Department of Physics</div><div class="">Phone: (412) 268-2745<span class="Apple-tab-span" style="white-space: pre; "> </span> <span class="Apple-converted-space"> </span>Carnegie Mellon University</div><div class="">Fax: (412) 681-0648<span class="Apple-tab-span" style="white-space: pre; "> </span> Pittsburgh, PA 15213</div><div class=""><a href="mailto:curtis.meyer@cmu.edu" class="" target="_blank">curtis.meyer@cmu.edu</a> <a href="http://www.curtismeyer.com/" class="" target="_blank">http://www.curtismeyer.com/</a><br data-mce-bogus="1"></div><div class=""><br class=""></div><div class=""><br class=""></div></div></span><br class="Apple-interchange-newline"></span><br class="Apple-interchange-newline">
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<br class=""><div><blockquote class=""><div class="">On Jan 21, 2016, at 11:37 AM, Richard Jones <<a href="mailto:richard.t.jones@uconn.edu" class="" target="_blank">richard.t.jones@uconn.edu</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class="">Tim,<div class=""><br class=""></div><div class="">I wasn't sure which dimension the 200 microns comes off of, but if it is the length (7.5cm) there is no need to fine-adjust that, 7.4 cm would work just as well.</div><div class=""><br class=""></div><div class="">-Richard J.</div></div><div class="gmail_extra"><br class=""><div class="gmail_quote">On Thu, Jan 21, 2016 at 11:08 AM, Timothy Whitlatch <span dir="ltr" class=""><<a href="mailto:whitey@jlab.org" target="_blank" class="">whitey@jlab.org</a>></span> wrote:<br class=""><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div class=""><div style="font-family: arial, helvetica, sans-serif; font-size: 12pt;" class=""><div class="">Hi All,<br class=""></div><div class=""><br class=""></div><div class="">I can get 5mm diameter precision ground tungsten carbide rod (twice the density of steel) 7.5cm long.<br class=""></div><div class=""><br class=""></div><div class="">This can be cut in half lengthwise and then the aperture cut in each half.<br class=""></div><div class=""><br class=""></div><div class="">With the wire EDM machining process we will loose about 200um but can overcome this by making additional pieces and matching them together.<br class=""></div><span class=""><div class=""><br class=""></div><div class="">Tim Whitlatch<br class="">Hall D Engineer<br class="">Jefferson Lab<br class="">600 KELVIN DR STE 5<br class="">Newport News, VA 23606-4468 <br class=""><a href="tel:757-269-5087" target="_blank" class="">757-269-5087</a><br data-mce-bogus="1"></div><br class=""></span><hr class=""><div class=""><b class="">From: </b>"Richard Jones" <<a href="mailto:richard.t.jones@uconn.edu" target="_blank" class="">richard.t.jones@uconn.edu</a>><br class=""><b class="">To: </b>"Timothy Whitlatch" <<a href="mailto:whitey@jlab.org" target="_blank" class="">whitey@jlab.org</a>><br class=""><b class="">Cc: </b>"Alexandre Deur" <<a href="mailto:deurpam@jlab.org" target="_blank" class="">deurpam@jlab.org</a>>, "Eugene Chudakov" <<a href="mailto:gen@jlab.org" target="_blank" class="">gen@jlab.org</a>>, "Hall-D Tagged Beam Group" <<a href="mailto:halld-tagger@jlab.org" target="_blank" class="">halld-tagger@jlab.org</a>><br class=""><b class="">Sent: </b>Thursday, January 21, 2016 9:19:31 AM<br class=""><b class="">Subject: </b>Re: Tungsten tube in primary collimator<br class=""></div><div class=""><div class="h5"><br class=""><div class=""><div dir="ltr" class="">Dear colleagues,<br class=""><div class="">Yesterday I promised to do a quick MC study to determine what a steel collimator insert with an aperture adjusted to allow the TAC to run safely with a 10 nA electron beam and a 2e-5 radlen radiator. The answers are given in a quick tech note that I link below. I am not done writing it yet, so if there are plots or results that you would like to see added please let me know. The bottom line is that steel will work just fine, and it only needs to be 15 cm long. The inner aperture diameter should be 1.1 mm. In response to Tim's question, tungsten would be better of course, but steel seems to work just fine and might be easier to work with.</div><br class=""><div class=""><a href="http://zeus.phys.uconn.edu/halld/collim-1-2016/collim-1-2016.pdf" target="_blank" class="">http://zeus.phys.uconn.edu/halld/collim-1-2016/collim-1-2016.pdf</a><br class=""></div><br class=""><div class="">-Richard Jones</div></div><div class="gmail_extra"><br class=""><div class="gmail_quote">On Thu, Jan 21, 2016 at 7:55 AM, Timothy Whitlatch <span dir="ltr" class=""><<a href="mailto:whitey@jlab.org" target="_blank" class="">whitey@jlab.org</a>></span> wrote:<br class=""><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div class=""><div style="font-family: arial, helvetica, sans-serif; font-size: 12pt;" class=""><div class="">Hi All,<br class=""></div><br class=""><div class="">In speaking with the machine shop, we can take a precision ground tungsten rod and cut it in half long wise with wire EDM.<br class=""></div><div class="">We can then cut a 1.5mm diameter half hole in each half.<br class=""></div><br class=""><div class="">Both halves would then be put in the 5mm primary collimator hole together giving us a 1.5mm hole (or what diameter is needed).<br class=""></div><br class=""><div class="">Tim Whitlatch<br class="">Hall D Engineer<br class="">Jefferson Lab<br class="">600 KELVIN DR STE 5<br class="">Newport News, VA 23606-4468 <br class=""><a href="tel:757-269-5087" target="_blank" class="">757-269-5087</a><br class=""></div></div></div></blockquote></div></div><br class=""></div></div></div></div></div></blockquote></div><br class=""></div>
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