The egs_chamber sample input files don't run out-of-the-box

[ftessier]

The sample input files provided in the egs_chamber application directory are complex, and moreover depend on a BEAMnrc source or materials that are not readily available. Hence, the examples don't run out-of-the-box after a fresh EGSnrc install. Also, a much simpler sample input file (pencil beam on slab) would prove useful.

Specifically, this was reported by Dave Rogers on 8 March 2014, but was never fixed:

1. example1 uses a beam source as input and since this BEAM model is not
   part of the distribution, one cannot run the example. I would propose that
   source be commented out and a simpler point source be used. Leave the beam
   source there to show how it would be done, but it is better if an example
   input file will actually run. Also, near the top say that it needs
   521icru.pegs4dat to run.

2. example2 makes use of materials that are not on the distribution (e.g.
   C173521ICRU) so these materials should be changed to similar materials in
   521icru and a similar note added to the top of the file re using 521icru.

[mxxo]

Just to add to this, example1_co60_Pfactors.egsinp fails with this error:

$ egs_chamber -i example1_co60_Pfactors.egsinp -p 521icru
In EGS_Application::initSimulation()
**********************************************
**********************************************
**********************************************

createGeometry: Error: multiple geometries with the same name exist: chamber_in_water