FDC Material and Noise Rates

[Matthew Shepherd <mashephe@indiana.edu>]

I've posted a Wiki page outlining Richard's changes to FDC geometry  
(Richard, check this!) and also some plots showing noise rate in the  
FDC vs. plane number and also in the TOF.  There is a significant  
difference -- for example the new geometry halves background rates in  
the TOF.

This also probably highlights the sensitivity of our background rate  
calculations to material in the beam line.  We should think about  
whether or not there systematic errors in these studies that might  
cause us to significantly miscalculate the backgrounds.

The plots can be found under the FDC page on the Wiki:

http://www.jlab.org/Hall-D/software/wiki/index.php/ 
Impact_of_FDC_Design_on_Noise_Rates

Mihajlo is working on evaluating the changes in FCAL photon  
reconstruction efficiency.

-Matt