Radiation length plots

[David Lawrence <davidl@jlab.org>]

Hi Richard,

    I am trying to reproduce some of the plots you showed at the last 
collaboration meeting on the integrated material in radiation lengths as 
a function of z. I am doing this using the mcTrajectoryPoint structures 
which includes the radiation length of the current material in the 
current step (RADL from GCMATE common) and the step size (STEP from 
GCTRAK common).

    One problem that I'm having is that, I do no see any gradual slope 
in areas with air such as between the FDC packages. In your plots, I can 
see some slight slope as one would expect.

    I'm also a little confused that on your plot of 0 to 0.5 degrees, a 
single FDC package looks to be right about 1% of a radiation length. 
Looking at the HDDS files for the geometry used at the time of the DC 
review (which I think is the geometry you used for these plots) I get 
1.32% of a radiation length per package.

    My questions for you are:

1.) Exactly how did you produce the plots you showed at the 
collaboration meeting?

2.) What geometry did you use to produce those plots? (Was it the 
current one in SVN at the time of the collaboration meeting?)

Thanks.


Regards,
-David

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  David Lawrence Ph.D.
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