[Halld-tagger] Tungsten tube in primary collimator

[Timothy Whitlatch]

Yes, off the diameter. It would leave a 200um gap at top. 

We can overcome this by making 2 custom pieces, so not a big deal. 


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


From: "Curtis A. Meyer" <cmeyer at cmu.edu> 
To: "Richard Jones" <richard.t.jones at uconn.edu> 
Cc: "Timothy Whitlatch" <whitey at jlab.org>, "Hall-D Tagged Beam Group" <halld-tagger at jlab.org>, "Egiyan, Hovanes" <hovanes at jlab.org> 
Sent: Thursday, January 21, 2016 12:25:56 PM 
Subject: Re: [Halld-tagger] Tungsten tube in primary collimator 

I think it comes of a diamater, not the length. That leaves a small “crack” along the top?? 
------- 
Prof. Curtis A. Meyer Department of Physics 
Phone: (412) 268-2745 Carnegie Mellon University 
Fax: (412) 681-0648 Pittsburgh, PA 15213 
curtis.meyer at cmu.edu http://www.curtismeyer.com/ 








On Jan 21, 2016, at 11:37 AM, Richard Jones < richard.t.jones at uconn.edu > wrote: 

Tim, 

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. 

-Richard J. 

On Thu, Jan 21, 2016 at 11:08 AM, Timothy Whitlatch < whitey at jlab.org > wrote: 

BQ_BEGIN

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: 

BQ_BEGIN

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 





BQ_END


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