MCPhoton

MCPhoton can currently be used to model the attenuation of a 1 MeV photon beam through a iron shield 10 mfp thick. It can either linearly or logrithmicly interpolate cross section data. It also has three options for modelling inchorrent photon scattering: 1. Using a constant rejection function 2. Using a linear rejection function or 3. Using Kahn's two path method.

This shows how to download and build MCPhoton with the desired data interpolator and polar angle rejection technique.

1. DOWNLOAD

a) In the desired directory enter the following into the command line:

$ git clone https://github.com/lkersting/MCPhoton.git

2. UPDATE ROOT DIRECTORY

a) Enter the MCPhoton src directory and open the CMakeLists.txt

$ cd MCPhoton/src
$ gedit CMakeLists.txt

b) At the top of the file change DIRECTORY to the directory in which MCPhoton was download. For example: the path to my copy of MCPhoton is "/home/lujoke/Documents/CPP/MCPhoton" so the first 4 lines look as follows

SET(DIRECTORY
  ${DIRECTORY}
  /home/lujoke/Documents/CPP
) 

2. COMPILE

a) Return to the MCPhoton directory and enter the following:

$ mkdir build
$ cd build
$ cmake ..

b) If you are not compiling for the 1st time, clean out old file. (NOTE: If you don't your inertpolation options might not update)

$ make clean

c) Choose the desired data interpolator and polar angle rejection technique: [rejtech] constant, linear, or twopath [interpolator] lin or log

$ make [rejtech]_[interpolator]

So if you want to use a linear rejection technique and linearly interpolate cross section data you would enter:

$ make linear_lin

3. RUN PROGRAM

a) From build run the exacutable (located in build/src)

$ ./src/MCPhoton

b) Follow the onscreen command to enter the radius for the ring "detector".

c) Follow the onscreen command to enter the # of photons to be modeled. NOTE: the number cannot be in entered in shorthand.
ie: 10000 (correct)
1E4 (Incorrect)

After running it will display: how many photons were transmitted, reflected, absorbed, the flux approximated by a buildup factor, the total time it took the program to run.

If any photons were transmitted it will display: the scalar flux (normalized to an area of 1 cm^2), the ring flux (normalized to the area of a ring of your chossing), and the location of the histogram txt file

Finally, it will produce two txt files located in the MCPhoton directory: A histogram of the transmitted photon energies and A file with the x & y coordinates as well as the cosine crossing angle with repect to the z plane (mu).