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computational physics

A toy Monte Carlo criticality code

Here's a quick implementation of a Monte Carlo neutron transport code for calculating the criticality eigenvalue (i.e. \(k_{\mathrm{eff}}\)) for a fissile system (in slab geometry).

This complements other 1D toy codes for radiation transport I've written: snes, which calculates \(k_{\mathrm{eff}}\) using the (deterministic) discrete-ordinates method, and fcimc, an implicit Monte Carlo thermal radiation code that models a Marshak wave in an optically thick medium.

Implicit Monte Carlo (1)

Implicit Monte Carlo (IMC) is a Monte Carlo method for solving the thermal radiation transport equation, published by Fleck and Cummings in 1971 , according to which:

The method is based upon the concept of effective scattering, wherein a fraction of the radiative energy absorbed is instantaneously and isotropically reradiated in a manner analogous to a scattering process.

This post gives a quick summary.