Email from Roger:

From carlini@jlab.org Fri Sep 17 11:09:12 2004
Date: Fri, 10 Sep 2004 09:51:54 -0400
From: Roger D. Carlini 
To: finn@physics.wm.edu, 'Neven Simicevic' ,
     'Jim Birchall' ,
     'Dave Mack' , 'Juliette Mammei' ,
     'Klaus Grimm' , armd@jlab.org, 'Mark Pitt' ,
     'Allena Opper' , 'Greg Smith' ,
     'Norman Morgan' , 'Mike Finn' ,
     'Yongguang Liang' ,
     'Shelley Page' ,
     'Tony Forest' 
Cc: carlini@jlab.org
Subject: Re: Qweak- Collimator Working Group

    [ The following text is in the "windows-1252" character set. ]
    [ Your display is set for the "ISO-8859-1" character set.  ]
    [ Some characters may be displayed incorrectly. ]

Hi Folks:

I was talking to Peter Bosted this morning and he made a couple of observations based on the experience of E158.

1)  We might reconsider puting ~5 radiations lengths of Pb in front of each quartz bar. He asserts than this will start 
a shower and effectively increase our signal to background (if any).

2)  The Pb will also filter out most of the very low energy backgrounds which Monte-Carlo's typically underestimate badly.

3)  We should consider a few reference tubes next to ones attached to the quartz as a way to measure any dilution 
backgrounds being produced in the tube itself. This was a serious problem in E158 and they never really figured out the 
mechanism.

I believe all these ideas potentially have merit, but there need at SLAC might have been far more essential owing to the 
high energies and small angles involved. I suggested he discuss these ideas with Dave Mack and Co.

Best Regards

Roger