The code I have used to compute light guide collection acceptances for the
Bcal (See GlueX-doc-1077 and GlueX-doc-959) are stored under svn at svn ls
https://halldsvn.jlab.org/repos/trunk/home/elton/geantguide The original
code came from Blake (UofR) and modified to suit my application. At the
moment it is not very organized (i.e. almost caos), although I think it
was giving reasonable results. If anyone wants to use it they should
contact me for more details.
My own suggestion to begin light guide simulations would be to find out
more about IU's GEANT4 stand-alone simulations. There are some updates
on reflectivities that are more realistic than the ones in GEANT3 (Matt
can correct me). Matt provide your own take on this.