Photoelectric effect, EM thresholds

I was exploring the options of simulating the photoelectric effect with photons just above the work function of general metals (~5-10 eV range), however, it seems that electron/photon transport at these energies is generally not supported/implemented in Fluka. Am I right or is there a way to set such low thresholds?

Hello Sebastian,

Indeed, the lowest photon transport threshold one can set in FLUKA is 100 eV, which is unfortunately well above your requested 5-10 eV range.

At such low energies, MC transport schemes face difficulties: the photon wavelength stretches over a large number of interatomic distances, so the underlying assumption of a particle undergoing interactions on individual target atoms/nuclei would suffer too much.

Furthermore, to resolve low-energy excitations of the irradiated solid (promoting electrons from some loosely bound valence state to a state above the Fermi level) one would need decent electronic (band)structure information, which is so highly dependent on crystalline structure, local chemical environment and so on, that it’s out of reach for a general-purpose MC transport code, where (a mixture of) photon cross sections on free atoms are used, assuming a homogeneous and isotropic material with a given atomic density (disregarding aggregation effects which do matter in your case). And this without entering in the specificities of low-energy electron transport.

FLUKA can at most transport optical photons for you, but this will be done essentially according to geometrical optics (no longer will there be explicit photoelectron emission) and with substantial input from the user (see the chapter of the manual on optical photons to have a general idea).