Re: Hodoscope location

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

Tim,

If you mean 20cm of open space normal to the window, I don't think we 
want that much distance between the window and the detectors.  At a 
crossing angle of 10 degrees, that would mean more than 1m of electron 
trajectory after the window.  Of course, we are talking about shrinking 
the vacuum chamber by 20cm, not moving the focal plane by 20cm, right?  
Yang can tell you that moving the focal plane is a much bigger job!  You 
could gain that space by shrinking the vacuum chamber, but it would 
affect our resolution.  We could simulate it, but I am pretty sure that 
the effect would be significant degradation in the resolution.

Richard Jones



Tim Whitlatch wrote:
> Hi all,
>
> How critical is the spacing  (air gap) between the hodoscope 
> scintillators and the vacuum window? Is 20 cm ok to allow a mechanism 
> for a window cover during maintenance? If not, we will have to slide 
> the protective plate over the window.
>
> Thanks,
>
>
>    Tim