Geometries for 2008 DC Review

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Geometry Files

The text below was copied and modified slightly from the README file originally written to describe the geometry files: 

Here are some files used to produce radiation length scans 
for the Feb 1, 2008 FDC review. Here is the source of each of the four 
geometries:


march2007
--------

This was the geometry used for the March 2007 DC review obtained via:

  svn cat -r 2403 https://halldsvn.jlab.org/repos/trunk/src/programs/Simulation/HDGeant/hddsGeant3.F > hddsGeant3.F

The resulting file had a global search and replace of "stemax = 0" to
"stemax = 1" in order to get a proper scan with AUTO set to zero in
the control.in file.


wiresonly
---------
This was modified from revision 3198 of:

https://halldsvn.jlab.org/repos/trunk/home/davidl/devel/FDCwiresonly/src/hdds

The CentralDC, StartCntr, and CerenkovCntr files were copied from the 
main trunk and the location of the Cerenkov master volume was modified
by hand in main_HDDS.xml from z=407 to z=466 to be consistent with the
baseline geometries. This really doesn't matter for tracking, but can save
some explanation when showing the plots.

This also was the only executable made from different HDGeant source (sans
the hddsGeant3.F file obviously). This used the code in the following:

https://halldsvn.jlab.org/repos/trunk/home/davidl/devel/FDCwiresonly/src/HDGeant_calib


CD3_dualcathodes
--------
This was a modified version of revision 3198 from:

https://halldsvn.jlab.org/repos/trunk/src/programs/Simulation/HDGeant

The modifications were:
1. Replace the FDK1 and FDJ1 volumes in forwardDC_chamber_2 with
   FDK2 and FDJ2. Similarly for packages 3 and 4. This I believe was
	a typo and I notified RTJ via e-mail. However, I did not commit the
	changes since I wanted him to verify them first  and commit them himself.

2. Replace the material type in FDJ1, FDJ2, ... with pure Kapton. The
	repository version used CopperKaptonEpoxy with I think was another
	typo. Similarly, RTJ was notified, but I kept the changes local.


CD3_dualcathodes_nocables
--------
This is an axact copy of the CD3_dualcathodes geometry except the signal cables
have been commented out completely.

CD3_singlecathodes
-------
This used a modified version of the baseline hddsGeant3.F file. A set of 4
volumes were defined (FDL1, FDL2, FDL3, and FDL4) that corresponded to
the FDK1, ... volumes. These were used to replace the second(downstream)
cathode plane with 26 microns of "AluminizedMylarFilm".

Radiation Length Scans

Integrated radiation lengths vs. theta in the region of the FDC support frames.

Here are some radliation length scans done using (some of) the geometries above.

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