<html><body><div style="font-family: arial,helvetica,sans-serif; font-size: 12pt; color: #000000"><div>Hi All,<br></div><div><br data-mce-bogus="1"></div><div>I can get 5mm diameter precision ground tungsten carbide rod (twice the density of steel) 7.5cm long.<br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div>This can be cut in half lengthwise and then the aperture cut in each half.<br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div>With the wire EDM machining process we will loose about 200um but can overcome this by making additional pieces and matching them together.<br data-mce-bogus="1"></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><br><hr id="zwchr" data-marker="__DIVIDER__"><div data-marker="__HEADERS__"><b>From: </b>"Richard Jones" <richard.t.jones@uconn.edu><br><b>To: </b>"Timothy Whitlatch" <whitey@jlab.org><br><b>Cc: </b>"Alexandre Deur" <deurpam@jlab.org>, "Eugene Chudakov" <gen@jlab.org>, "Hall-D Tagged Beam Group" <halld-tagger@jlab.org><br><b>Sent: </b>Thursday, January 21, 2016 9:19:31 AM<br><b>Subject: </b>Re: Tungsten tube in primary collimator<br></div><br><div data-marker="__QUOTED_TEXT__"><div dir="ltr">Dear colleagues,<br><div>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><div><a href="http://zeus.phys.uconn.edu/halld/collim-1-2016/collim-1-2016.pdf" target="_blank">http://zeus.phys.uconn.edu/halld/collim-1-2016/collim-1-2016.pdf</a><br></div><br><div>-Richard Jones</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Jan 21, 2016 at 7:55 AM, Timothy Whitlatch <span dir="ltr"><<a href="mailto:whitey@jlab.org" target="_blank">whitey@jlab.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div><div style="font-family:arial,helvetica,sans-serif;font-size:12pt;color:#000000"><div>Hi All,<br></div><br><div>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></div><div>We can then cut a 1.5mm diameter half hole in each half.<br></div><br><div>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></div><br><div>Tim Whitlatch<br>Hall D Engineer<br>Jefferson Lab<br>600 KELVIN DR STE 5<br>Newport News, VA 23606-4468 <br><a href="tel:757-269-5087" target="_blank">757-269-5087</a><br data-mce-bogus="1"></div></div></div></blockquote></div></div><br></div></div></body></html>