High-fidelity treatment for object movement in time-dependent Monte Carlo transport simulations

TL;DR

This paper evaluates a time-dependent surface method in Monte Carlo simulations for modeling moving objects, demonstrating it is more accurate and efficient than traditional stepping methods and robust in complex scenarios.

Contribution

It introduces and assesses a time-dependent surface technique for object movement in Monte Carlo transport, showing its advantages over existing methods in accuracy and efficiency.

Findings

Time-dependent surface method outperforms stepping approximations in efficiency.

The technique remains accurate where at-source geometry adjustments fail.

Validation against a benchmark confirms the method's reliability.

Abstract

We investigate the use of time-dependent surfaces in Monte Carlo transport simulation to accurately model prescribed, continuous object movements. The performance of the continuous time-dependent surface technique, relative to the typical stepping approximations and the recently proposed at-source geometry adjustment technique, is assessed by running a simple test problem involving continuous movements of an absorbing object. A figure of merit analysis, measured from the method's accuracy and total runtime, shows that the time-dependent surface is more efficient than the stepping approximations. We also demonstrate that the time-dependent surface technique offers robustness, as it produces accurate solutions even in problems where the at-source geometry technique fails. Finally, we verify the time-dependent surface technique against one of the multigroup 3D C5G7-TD benchmark problems.