11. Examples

This chapter contains some examples of using reference application for radiation transport simulations. Configuration files format is not explained here in detail. See complete description in the chapter Reference application

11.1. Simple bremsstrahlung

In order to run simulation of bremsstrahlung production using reference application you need to prepare two task description XML configuration files.

Here is an example of first one geometry description file G_Target.xml:

<?xml version="1.0" encoding="utf-8"?>
<accelerator>
    <!--Tungsten target-->
    <module type="cylinder" name="Target" medium="W700ICRU" density="1">
        <Color r="0" g="0.5" b="1" t="0.2" />
        <position unit="cm" x="0" y="0" z="0" />
        <normal x="0" y="0" z="1" />
        <xaxis x="1" y="0" z="0" />
        <size unit="cm" radius="1.0" height="0.2"/>
    </module>
    <module type="planefilter" name="Trap" medium="AIR700ICRU" density="1">
        <Color r="0" g="0.5" b="0.5" t="0.8" />
        <position unit="cm" x="0" y="0" z="0.2" />
        <normal x="0" y="0" z="1" />
        <xaxis x="1" y="0" z="0" />
    </module>
</accelerator>

Geometry consists of two modules. First is cylindrical tungsten target with front plane located in the coordinate system origin. Its Z axis directed along the world Z axis. Target thickness is 0.2 cm and radius is 1.0 cm.

The second module is a plane filter dedicated to host scoring object defined in simulation file. It is located at the level of back plane of the target (z = 0.2).

Next is an example of simulation description file S_Target.xml:

<?xml version="1.0" encoding="utf-8"?>
<!-- Bremsstrahlung production by electron beam on the target -->
<input>
    <simulation nhistories="100000" nbanches="10">
    </simulation>
    <options>
        <vrmlfile>PlaneScore.wrl</vrmlfile>
        <statfile>PlaneScore.dat</statfile>
        <transCutoff_elec unit="MeV" ecat ="0.0"/>
    </options>
    <source name="Electron beam" module="Target" trackparticles="false">
        <radiation type="electron" energy="6.0" />
        <shape direction="conical" size="0.00" angle="0"/>
        <position unit="cm" x="0" y="0" z="-1.0" />
        <direction x="0" y="0" z="1" />
    </source>
    <score type="fluence_plane" module="Trap" pt="photon"/>
</input>

This file prescribes 1E6 particles, which sampling from “Electron beam” source. Point source is located at the world Z axis at -1.0 cm distance from its origin and emits electrons with energy 6 MeV along Z axis. First object that electrons will hit is directly indicated and it is module “Target”.

Scoring type is “fluence_plane”. It is connected to module “Trap”. Scoring is accounting only photons. Electrons and negatrons will be ignored.

To start simulation go to the directory of the simulation configuration files and run the following command:

MCSimulator S_Target.xml G_Target.xml

Note

MCSimulator requires that PEGS file AcceleratorSimulator.pegs4dat must be located at ../data folder.

Next figure (Fig. 11.1.1). shows screenshot of simulation process.

Fig. 11.1.1 Simulation process screenshot.

Simulation will produce two files. According to configuration simulation scene will be written in VRML graphical format file PlaneScore.wrl. Next figure (Fig. 11.1.2). shows its content in VrmlView application.

Fig. 11.1.2 Simulation scene graphical view.

Second file PlaneScore.dat is a dump of scoring content. In this case it is simple text file with a few distributions, which easily can be analyzed, for example, in EXCEL. Next figure (Fig. 11.1.3). shows mean energy distribution depending on direction as an example.

Fig. 11.1.3 Statistic on mean photon energy distribution depending of direction of bremsstrahlung.