Electron beam hitting the Tungsten target creates XRay photons. How do I define the resulting photons source since openMC cant simulate electrons

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hi everyone,
I am trying to simulate Linear Accelerator (LINAC) Head using OpenMC. In LINAC an electron beam hits the high Z target and as a result XRay photons are emitted. As OpenMC cant simulate electrons so I was looking for an alternative approach like defining an XRay photon source right after the target material.
Could you please help me defining such a source?

Monte-Carlo-model-of-a-linear-accelerator-and-DOSXYZ-phase-space-file-phsp-export
Monte-Carlo-model-of-a-linear-accelerator-and-DOSXYZ-phase-space-file-phsp-export648×669 84.6 KB

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Hi Mani,

my top recommendation would be to simulate the setup with MCNP mode p e. Write a phase-space file (wssa/rssa) where you want to propagate the photons from (so writing the photons after the target).

Then convert that rssa to mcpl format, and use that mcpl source in OpenMC.

Of course you are probably wanting to use OpenMC so not to have MCNP…
I am not familiar with EGS (DOSXYZ), but I presume there is a way you can write a phase-space file with it. You should be able to convert that phase-space file to mcpl format or OpenMC hd5 format.

The MCNP direct to MCPL is fairly straightforward.
The second way requires a bit more data handling/gymnastics.

You could also use a general source in OpenMC if you know approximately the energy, x,y,z,u,v,w.
(say from a uniform disc propagating photons along direction Z, at energy E MeV)

Perry

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thank you Perry! i want to use GEANT4 instead do you have any idea if its possible to import phasespace file from GEANT4 into openmc?

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Yes, it is possible.
The MCPL phase-space file generated through the MCPL-Geant4 workflow can be directly used in OpenMC.

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Hello,

I am interested in solving a very similar problem; basically I want to know the source rate from an electron beam hitting a solid target. I imagine there may be two ways to do this in OpenMC.

  1. Create an electron particle source at the desired energy and let OpenMC calculate the resulting Bremsstrahlung radiation.

In the original post it is mentioned that OpenMC can’t simulate electrons, but in openmc.IndependentSource.particle you can specify ‘electron’ as a source particle type. It doesn’t seem like OpenMC can actually transport electrons and just immediately makes the thick-target bremsstrahlung approximation. If this is the case, maybe I could create an electron particle source in my target material and have all the bremsstrahlung radiation emitted in a similar way to a beam hitting the target.

  1. Calculate the bremsstrahlung radiation myself and create a corresponding photon source at the target.

This is mentioned in the original response to the post and would be my preferred solution if idea #1 doesn’t work. I don’t have access to MCNP or GEANT4 so I would solve for the emitted radiation by hand and apply it in the OpenMC model.

Please let me know which of these solutions is feasible; thank you!