-- 

Nathan Rodning
Professor of Physics
(780) 492-3862  /  Fax:  (780) 492-0714
http://www.thehungersite.com/

An embedded message follows:

From: Robert Henderson <rhend@triumf.ca>
Date: Thu, 23 Aug 2001 17:34:21 -0700
To: Nathan Rodning <rodning@relay.phys.ualberta.ca>
Subject: Tilting Cradle


---

Hi Nate,

  Attached you will find a postscript drawing of the US half of the
Cradle.

  The magenta line shows the limits of the carious active areas (320 mm
dia. for PC1 plane and fully-instrumented DC planes, 256 mm for 6 of the
dense satck planes and 96 mm diameter for target module.) .

  The three blue lines indicate possible amounts of cradle titlt.

(1) The line at 9.1 degrees shows the maximum tilt of cradle that still
allows a full 96 mm diameter `cylinder' to pass               through the
US end-plate, inclue the target active area and leave through the DS
end-plate.

(2) The 12.4 degree line shows that just a few degrees later there is now
zero solid angle for particles through both end plates. Tthere is still a
48 mm wide (horizontal) region where particles pass through the US
end-plate, then throught the 12-detector stack, but those particles now
hit the DS endplate.

(3) The 15.6 degree line shows that, by this angle, no particle that
passes through the US endplate will touch the target active area.

  This summary of the situation makes no allowance for the angle spread
of the incoming beam (since I don't know it). But to me it seems that
tilting the cradle does little good, We can only get to 9.1 degrees to
include both our trigger scintillators. After that the sold angle drops
very quickly.

Regards Robert Henderson

Filename: Limits2.eps

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