Monte Carlo Simulation of a $^{198}$ Au Thin Foil: The Response of a $4\pi \beta \hbox {-} \gamma$

Monte Carlo simulations have been performed of the decay of a ¹⁹⁸Au solid source within a 4pibeta- gamma coincidence detector. Calculations of the proportional counter efficiency to both beta and gamma emissions are simulated. A comparison of results obtained using the MCNP-5 and Geant4 simulation packages indicates that Geant4 better evaluates the K correction to the coincidence equation than MCNP-5 predictions. This difference can be accounted for in terms of how the codes handle the physical interactions occurring in the foil and surrounds.