Re: exhalo drawings

[Peter Kammel <kammel@three.npl.uiuc.edu>]

Dear Peter,

On Fri, 8 Sep 2006, Peter Winter wrote:

> Dear all,
> 
> I also looked at your drawings and I haven't found any obstacles. I 
> reviewed that we can really push in far enough to reach the center of 
> the beamline for being able to turn by 180 degrees. Since the NW320 
> beampipe has a radius of ~16 cm, we'd maximally need this as being 
> movable. Since the aluminium tube around the light guide is 26 cm and 
> the feedthrough is <10cm, it's fine to me.
> Just a few comments left from my point of few:
> - In your drawing the two scintillators are mounted by 90 degrees. We 
> could also have them opposite at 180 degrees. I cannot really think of 
> any disadvantages / advantages for both options since we'll anyhow 
> rotate in phi to scan the different regions.

I agree. The 90 deg was preferable, when I tried to make the light guide
to fit into the 32 cm. That is not possible, but we can sneak it in
through the short NW40. So I also don't see a clear preference.

> - Concerning the connection of the plexi glas and the aluminum 
> protection: With respect to the vacuum glueing both together is never 
> good as the vacuum . But since that might be the only option we will 
> probably do that. I can ask Mr Bracher later if he (as the scintillator 
> and lightguide expert at PSI) has some better idea.

Good idea to ask the them. Also take the existing pipe for comparison.
Wrapping with Alu at the inside has the advantage that it does not
matter if the glue flows a bit to the inside. Whether my suggested
.2 mm radial gap is correct, should also be discussed.

> - The vacuum group will order the special dynamic feedthrough components 
> and they'll prepare the drawings for our dimensions. I will then figure 
> out where we can build the different parts (workshop east or west).
> - During the time period where I'm gone you can always contact Claude 
> and ask him to help with the local communication. He just agreed on that.

Thank you.

> - Does the plexi tube need any special treatment at the ends (like a 
> notch for the UIUC light guide or is a flat surface fine?

I cannot answer now. It depends how John makes the light guide. Can
one reach Mr Bugmann by email?

> - Concerning the scintillators: For the APD preparation we have three 
> 100x10x1mm scintillators. We also have a larger piece left from Peter's 
> reserve from which we could get 2 pieces at 100x20mm. However, this is 
> only 0.5mm thick.
> Peter
> 
Ideally, Mr Bacher could make 2 new 1mm pieces?


Have a great vacation


Peter