Re: size of diamond and goniometer frame for hallD

[Richard Jones <richard.t.jones@uconn.edu>]

Yves,

That's great.  The rounder we can make the beam at the radiator the better off we will be, I think.  reducing the beam sigma to 0.5mm in x to make it similar to sigma_y at the radiator, keeping it the same at the collimator, would be outstanding.  We would have to do more spot moves, but moving the crystal around is relatively quick.  It also gives us more flexibility in terms of avoiding bad spots on a crystal, less sensitive to large-scale deformations of the crystal, and even smaller crystals would be usable.  I would not like to see the spot get smaller than 0.5mm in x or y, but making it close to round makes things simpler.  Thanks for the good news of these improvements.

Richard Jones

yves roblin wrote:

Richard,

 Thank you for the information.

 

How small can I make the beam in sigma_x and  not reach a current density that would damage that diamond  (Right now I have sigma_x=1mm and this is what I gave you last year too).

With our new optics (Double bend achromat), we reduced the emittance by roughly another factor of 2 which means  that I can make the beam 40 % smaller for the same quad settings (or relax the quads and keep the beam to whatever size you need). The idea behind a smaller beam is that of course, we would have even less halo.

 

Yves