FW: Influence of the gate valve

["David W Hertzog" <hertzog@uiuc.edu>]

-----Original Message-----
From: Winter Peter [mailto:peter.winter@psi.ch] 
Sent: Friday, May 12, 2006 6:55 AM
To: Winter Peter; hertzog@uiuc.edu
Cc: rmcnabb@uiuc.edu; jblackbu@uiuc.edu
Subject: RE: Influence of the gate valve

I just saw that one dimension is wrong in my drawing, namely the wide
tube is not 355cm but ~315cm. That's even better since then two
calculated distances change, namely the 50mm becomes 30mm and the 105mm
is an 85mm. Therefore, the loss due to the gate valve is now:

(30-x) / 300 = (85-30) / 693  ==> x = 6mm.

Anyhow, I think that our beam is far smaller so that this shouldn't
affect us (is that right?).
Peter

-----Original Message-----
From: Winter Peter
Sent: Fri 5/12/2006 12:12 PM
To: hertzog@uiuc.edu
Cc: rmcnabb@uiuc.edu; jblackbu@uiuc.edu
Subject: Influence of the gate valve
 
Hi,

as I mentioned this week I put together a sketch of the current
beamline. I drew the part starting at the center of the last quad until
the window flange where the EMC would follow. The sketch is in drawn in
a scale of 1:5 and all measures are in mm. Since we have our lst focus
in the last quad I start with the extreme case of a muon just touching
the wall in the center of this last quad. This muon will reach the EMC
if it just hits the edge where the beam pipe is reduced. This is the
upper blue line.
Now the red shaded area is the reduction due to the current version with
the gate valve. You can see that this 'extreme' muon now is stopped by
the gate valve. The bottom blue line in comparison shows the most
'extreme' possible muon with the gate valve. From geometry, I calculated
the offset x from the wall at the center of the last quad to be x=2.6cm
((50mm-x)/300mm = (105mm-50mm)/693mm). That is with the gate valve as
planned until no, we'd only accept the beam if it is more than 2.6cm
away from the wall. 
So if we want to get to the oldacceptance we have to shift the gate
valve more downstream by ~20cm. So we have to discuss that because
that'll affect John's part, too, since he'll need 20cm less in the
adjustment to have the target in the center.
Peter