[Halld-tagger] Tungsten tube in primary collimator

[Timothy Whitlatch]

Hi All, 

I can get 5mm diameter precision ground tungsten carbide rod (twice the density of steel) 7.5cm long. 

This can be cut in half lengthwise and then the aperture cut in each half. 

With the wire EDM machining process we will loose about 200um but can overcome this by making additional pieces and matching them together. 

Tim Whitlatch 
Hall D Engineer 
Jefferson Lab 
600 KELVIN DR STE 5 
Newport News, VA 23606-4468 
757-269-5087 


From: "Richard Jones" <richard.t.jones at uconn.edu> 
To: "Timothy Whitlatch" <whitey at jlab.org> 
Cc: "Alexandre Deur" <deurpam at jlab.org>, "Eugene Chudakov" <gen at jlab.org>, "Hall-D Tagged Beam Group" <halld-tagger at jlab.org> 
Sent: Thursday, January 21, 2016 9:19:31 AM 
Subject: Re: Tungsten tube in primary collimator 

Dear colleagues, 
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. 

http://zeus.phys.uconn.edu/halld/collim-1-2016/collim-1-2016.pdf 

-Richard Jones 

On Thu, Jan 21, 2016 at 7:55 AM, Timothy Whitlatch < whitey at jlab.org > wrote: 



Hi All, 

In speaking with the machine shop, we can take a precision ground tungsten rod and cut it in half long wise with wire EDM. 
We can then cut a 1.5mm diameter half hole in each half. 

Both halves would then be put in the 5mm primary collimator hole together giving us a 1.5mm hole (or what diameter is needed). 

Tim Whitlatch 
Hall D Engineer 
Jefferson Lab 
600 KELVIN DR STE 5 
Newport News, VA 23606-4468 
757-269-5087 




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