EGSnrc Test

[CuiHenry]

Hi，guys：
I defined a simple simulation using EGSnrc to study photon transport and dose distribution in Tungsten and aqueous media.
But after i run it, the results don't feel right.

Is the deposition energy of individual particles or the total deposition energy of the medium shown?
The attachment is my code.
slab.zip
Thanks!!!!

[rtownson]

This is due to the normalization of the collimated source, which is different from many of the other sources in EGSnrc. It is explored in the getting-started manual, but here is a better description:

https://nrc-cnrc.slides.com/ftessier/egsnrc-collimated-source/fullscreen

The TLDR is just to set distance in the collimated source to be 1/sqrt(4*Pi) (calculate the actual value and use that). This will normalize the results to be "per particle" as you expect. It does assume that you are modelling an isotropic source and just collimating it.

[CuiHenry]

tutor7pp.zip
OK!
I use tutor7pp, but i can't change the media = tungsten.
Unable to recognize new media name.
And with use egs_box, i can't make sure the right setting with 1 cm thick tungsten plate, because box size = 1 1 435.
It means 435mm is tungsten thickness?

Can you help to run it?

[CuiHenry]

I want to set the light source position at 435 from the plate 435.
How can i do ?

[rtownson]

Have you done the getting started manual? It will help you learn how to set materials and design geometries. If you are using -p tutor_data, it doesn't contain tungsten. Instead, learn how to use pegsless materials. E.g.

:start media definition:

    ### cutoff energies
    ae  = 0.521            # lowest  energy for electrons (kinetic+0.511)
    ap  = 0.01              # lowest  energy for photons   (kinetic)
    ue  = 30.511            # maximum energy for electrons (kinetic+0.511)
    up  = 30                # maximum energy for photons   (kinetic)

    :start air:
        density correction file    = air_dry_nearsealevel
    :stop air:

    :start tungsten:
        density correction file     = tungsten
    :stop tungsten:
:stop media definition:

Instead of egs_box you could use planes like you were in tutor2pp, and the same source design.

[CuiHenry]

I changed but it show me EGS_Application::initSimulation(): scoring initialization failed with status 4804176.
Use:
################################

AUSGAB OBJECTS

################################
:start ausgab object definition:

:start ausgab object:

    library = egs_track_scoring
    score photons   = yes
    score electrons = yes
    score positrons = yes

:stop ausgab object:

:stop ausgab object definition:

Can you tell me why?

testapp.zip

[rtownson]

For tutor7pp you need to at least have a scoring options input block, even if you don't use it. There are some inputs to allow you to score spectra. Just add these lines:

:start scoring options:
:stop scoring options: