[Halld-tagger] Tungsten tube in primary collimator

[Richard Jones]

Tim and all,

As far as I am concerned, the design you propose does the job. Being only
7.5 cm long also helps because being shorter makes the pointing of the axis
back at the radiator spot less critical. I would say to go for it. The only
change I would request is to reduce the diameter from 1.5mm to the range
1.0-1.1 mm, whatever works best for people who prefer English (actually
American) units.

-Richard Jones

On Thu, Jan 21, 2016 at 3:00 PM, Timothy Whitlatch <whitey at jlab.org> wrote:

> Alexandre,
>
> Thanks for trying to simplify (and lower the cost of) the pieces.
> The gap would not be the same all around
> The gap would only be on the top and bottom (or sides only). This may make
> it hard to center.
>
> The cost is about $1K for the custom pieces.
>
> I think we just do the 2 custom pieces, therefore we will know exactly
> what we have.
>
> Timeframe is about 2 weeks.
>
> Is it a go?
>
>
> Tim Whitlatch
> Hall D Engineer
> Jefferson Lab
> 600 KELVIN DR STE 5
> Newport News, VA 23606-4468
> 757-269-5087
>
> ------------------------------
> *From: *"Alexandre Deur" <deurpam at jlab.org>
> *To: *"Timothy Whitlatch" <whitey at jlab.org>
> *Cc: *"Curtis A. Meyer" <cmeyer at cmu.edu>, "Hall-D Tagged Beam Group" <
> halld-tagger at jlab.org>, "Hovanes Egiyan" <hovanes at jlab.org>
> *Sent: *Thursday, January 21, 2016 2:00:34 PM
>
> *Subject: *Re: [Halld-tagger] Tungsten tube in primary collimator
>
> If we wrap the tube in aluminum tape, the gap will be 100 um everywhere
> and filled with aluminum. It might be an acceptable and faster solution
> than machining custom pieces?
>
> Alexandre
>
> ----- Original Message -----
> > From: "Timothy Whitlatch" <whitey at jlab.org>
> > To: "Curtis A. Meyer" <cmeyer at cmu.edu>
> > Cc: "Hall D beam working group" <halld-tagger at jlab.org>, "Hovanes
> Egiyan" <hovanes at jlab.org>
> > Sent: Thursday, January 21, 2016 1:07:37 PM
> > Subject: Re: [Halld-tagger] Tungsten tube in primary collimator
>
> > 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:
> >
> >
> >
> > 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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