How can I learn and navigate the egs++ class library?

[jcampbell555]

I'm trying to experiment with making some new geometries and manipulating some of the example simulations in the EGS manual and the C++ class library but the library can be pretty hard to navigate. Is there any easy way to navigate these barriers or is it just sheer will and determination in learning each class? Is there an alphabetical list of all the libraries, classes, or commands? Any help would be appreciated.
Thanks!

[rtownson]

Here is a list of geometries, not sure why is isn't alphabetical:
https://nrc-cnrc.github.io/EGSnrc/doc/pirs898/group__Geometry.html

Here is a list of all the egs++ classes, which is alphabetical:
https://nrc-cnrc.github.io/EGSnrc/doc/pirs898/annotated.html

Essentially you have to combine the "common" input syntax (https://nrc-cnrc.github.io/EGSnrc/doc/pirs898/common.html) with the syntax you find for each of the sources, geometries, and ausgab objects on their respective pages.

Of course, let me know if you have any specific questions!

[jcampbell555]

@rtownson I know that egs_view uses levels of transparency to simulate energy of particles but is there a way to track the energy of a particle using a multitude of colors? Say for instance: 6 different colors for photons of energy 0-1 MeV, 1-2 MeV, 2-3 MeV, 3-4 MeV, 4-5 MeV, 5-6 MeV

[ftessier]

That would be a nice option in egs_view: color the particles by energy, say from blue to red, or to yellow on a viridis scale, between specified minimum and maximum (default to Emin to Emax).

[rtownson]

See the track alpha code in HEN_HOUSE/egs++/view/egs_visualizer.cpp:

if (energyScaling) {
    track_alpha = 0.2+0.8*image[idx].y;
}

Here, image[idx].y is the energy of the particle. So you could pretty easily add some lines to change the colour instead. You want to set bCol instead of track_alpha: it's an EGS_Vector of 3 RGB values. If you do this, of course feel free to share it or make a pull request.

[jcampbell555]

@rtownson I'm trying to create a gaussian beam that strikes a tungsten target but I'm having some trouble. I can simulate the tungsten target easily but the beam is more complicated. I know that the library used is egs_gaussian_shape but beyond that I'm unsure of the syntax. I've looked for examples but can't find any. Any help would be appreciated.

[rtownson]

If 'last case' = 'fluence', then it will report 'per particle' because the fluence equals the number of primary source particles. For some source types (e.g. collimated source, radionuclide source..), these will not be equal so it reports per fluence instead.

[jcampbell555]

@rtownson so if I wanted to convert from per fluence to per particle, how would i do that? Or rather if they are not equivalent, how is the total energy in the material calculated? Ex: if the fluence = 10, would I just multiply the Edep(per fluence) by 10?

[rtownson]

Which source are you using? You can multiply by the fluence and divide by last case, but per fluence is likely what you actually want. e.g. for the radionuclide source per fluence means per decay (or per disintegration) which is always what you want.

[ftessier]

One exception is the collimated source, where you might want to recover the result per emitted particle in 4*pi, in which case you simply divide the collimated source result by 4*pi, assuming the source distance input is set to 1 (default).

[ftessier]

There is one exception: for a collimated source you might want to recover the results per source particle in 4π. In that case, simply divide the results by 4π, assuming that the source distance parameter is set to 1 (the default). You need only multiply by the fluence for a single particle (1/4π for a unit sphere) to recover the result per particle!