Tallying in Energy Units and Using CollisionFilter

[kevinm387]

Hi All,

I have some basic questions related to tallying. Apologies if these are in the documentation already, I looked but still wasn’t sure about these.

1. Is there a way to get fluxes/currents in energy units (i.e. MeV/cm^2 and MeV), similar to MCNP’s *Fn flag? I can envision doing this manually with an EnergyFunctionFilter, but if there’s a built in way, that would clearly be better.

2. I’m also interested in tallying only uncollided particles from my source in a fixed source calculation. I believe the way to tally uncollided particles would be using a CollisionFilter([0]), does that seem correct?

3. Related to #2, are secondary particles considered “uncollided” by default, like in MCNP? Can you toggle that treatment so that secondary particles are not considered uncollided?

As always, thank you for the help!

[paulromano]

@kevinm387

Is there a way to get fluxes/currents in energy units (i.e. MeV/cm^2 and MeV), similar to MCNP’s *Fn flag? I can envision doing this manually with an EnergyFunctionFilter, but if there’s a built in way, that would clearly be better.

The only way to do this would be to use an EnergyFunctionFilter with two points (one for 0 eV and another for some arbitrary maximum energy, e.g. 100 MeV).

@kevinm387

I believe the way to tally uncollided particles would be using a CollisionFilter([0]), does that seem correct?

That is correct.

@kevinm387

are secondary particles considered “uncollided” by default, like in MCNP? Can you toggle that treatment so that secondary particles are not considered uncollided?

Yes, secondary particles are treated as uncollided. Right now we don’t have a toggle for this but it wouldn’t be difficult to add one and I can definitely see the value in having that.

[kevinm387]

Thank you @paulromano!