What are the Physical and Statistical laws behind this Monte Carlo simulation

[F-xy520]

Dear colleagues,

I am currently working on analyzing and modeling particle scattering properties, for which I am using a Monte Carlo simulation software. Concurrently, I also aim to model radiation fields based on fundamental physical formulas.
My primary questions regarding this Monte Carlo simulation software are:
Could you please clarify what underlying calculation formulas or algorithms the software is based upon?
Specifically, how does the software compute the trajectories and interaction dynamics of particles within a radiation field?
Any explanation or relevant documentation you could provide would be highly appreciated.
Thank you for your time and insights. I look forward to your valuable response.

Sincerely

[rtownson]

See chapter 2 of the EGSnrc core manual, pirs-701: https://nrc-cnrc.github.io/EGSnrc/doc/pirs701-egsnrc.pdf

[F-xy520]

Thank you!