From carlini@jlab.org Thu Sep  9 07:31:42 2004
Date: Wed, 08 Sep 2004 11:23:47 -0400
From: Roger D. Carlini 
To: finn@physics.wm.edu
Cc: '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' 
Subject: Re: Qweak working group - next meeting

Hi Mike:

As my message states there still is room for spokes to attach the inner and outer sections of shielding for all of Jim's 
simulations in his table, but this can be worked around mechanically if we wanted to have a really wide Delta phi run.

I believe Jim's table out to 12-8-24 don't have overlapping images. However, there is absolutely no physics or beam 
systematic reason to require the images not to overlap. The signals are added in software anyway.

The detector PMT's are out of the view of the scattered beam and behind the shielding - again see my previous sketch and 
email.

The frames on the sides of the chambers do not need to be behind shielding during the callibration runs if thaey are 
actively shielded by scintillators. HDC will accept wide angles, but I am not proposing you build them.  Also, If there 
are 16 independent bars (1 PMT + mirrored end) then a chamber need only cover one (narrow) bar at a time during 
calibration.

The idea was that we design a "universal acceptance" detector system. The scheme I suggested would result in narrower 
bars and allow pretty much any collimator concept to be used. We coulds have several collimator built. The calibration 
system needs to be designed around an experiment optimized for production running not the other way around.

I need to make a better drawing to circulate.

Best Regards

Roger