Re: new collimator cave drawings.

[Tim Whitlatch <whitey@jlab.org>]

Title:

Hi Richard,

Currently, Sasha is looking at some shielding optimization. Thanks for the feedback. I will answer your questions below;

1. The window diameter in the layout is 8 inches (see bottom view on .pdf). The 18.54 is the distance from the wall.

2. That is correct. We can look at Hall B design to see if that works.

3. That is correct. This layout would have  about half of the PS magnet inside the cave and half on the platform. Embedding the PS magnet in the shielding may be feasible if it meets our shielding requirements. Having it downstream of the shielding gives us the cleanest install which would not disturb the shielding if the ps had to be moved for any reason.

4. If required, we could ask facilities to have the opening moved. This will come at some design cost. If the shielding turns out to be adequate in the current configuration, we could leave it alone.

Cheers,
             Tim

Richard Jones wrote:

Tim,  here are our comments on your updated collimator cave drawings.

1. How do I read off the exit window diameter from the buried beam pipe upstream of the active collimator?  It seems that the buried pipe is 12" in diameter.  This couples to a short section with vacuum sensors that ends at the exit flange.  The exit flange diameter seems to show 18.54" that seems impossible.  What does the 18.54" refer to?
2. If we agree that there should be the ability to switch between multiple collimator stations then we need to think about how the primary collimator support table should look with the translation stage on it.
3. Where in this picture does the pair spectrometer magnet go?  Does it attach to the downstream exit port in the drawing?  If there is room to fit the pair spectrometer inside the hall, that would be great, but there is some real estate that could be saved by embedding the ps inside the concrete block at the exit to the cave.
4. Would it be possible to move the access door a bit upstream, and keep the thickness of the concrete shielding the same across the full width of the cave?

Richard Jones, Igor Senderovich

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