Email from Jim:

From jimb@mts.net Thu Sep 23 10:47:43 2004
Date: Sat, 18 Sep 2004 21:57:13 -0500
From: Jim Birchall 
To: Juliette Mammei , Roger Carlini ,
     Klaus Grimm , Mark Pitt ,
     Neven Simicevic , Greg Smith ,
     Allena Opper , Tony Forest ,
     Norman Morgan , Mike Finn ,
     David Armstrong , Yongguang Liang ,
     Shelley Page , Dave Mack ,
     Richard Jones 
Subject: Inelastic rates on the Cerenkov bar

Here are the rates I find on the Cerenkov bar from inelastics (REAC = 3 
only, ep --> en pi+) as a function of cut across the width of the bar 
with mini-torus field off for the 10-8-22, 9-8-22 and the standard 
8-8-22 Boston type collimators. There is no cut on the energy of the 
electron, just on the bar width.

10-8-22 collimator (maximum angle 14.5 degrees)
Cut on x (cm)   Elastic rate (MHz)  Inelastic rate (MHz) Percent 
inelastic
300-320  785   4.5  0.57%
300-318  771   2.4  0.31%
300-316  750   1.2  0.16%

The maximum angle let through by the 10-8-22 collimator is about 14.5 
degrees, which extends the upper edge of the moustache compared with 
the standard 8-8-22 Boston collimator (maximum angle 11.5 degrees).

9-8-22 collimator (maximum angle 13 degrees):
Cut on x (cm)   Elastic rate (MHz)  Inelastic rate (MHz) Percent 
inelastic
300-320  730  1.50  0.21%
300-318  717  0.64  0.09%
300-316  702  0.22  0.03%

The standard 8-8-22 Boston collimator, maximum angle 11.5 degrees:
Cut on x (cm)   Elastic rate (MHz)  Inelastic rate (MHz) Percent 
inelastic
300-320  624  0.19  0.030%
300-318  618  0.07  0.011%
300-316  609  0.03  0.005%

So, for the standard Boston collimator, the inelastic rate on the bar 
is up to 200 kHz, 0.03% of the elastics, depending on bar width. For 
9-8-22, the inelastic rate is up to 0.2%, for 10-8-22, up to about 
1/2%.

Jim