Hybrid Weight Window Method for Global Time-Dependent Monte Carlo Particle Transport Calculations

Fuente: arXiv
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Main Authors: Shaw, Caleb A., Anistratov, Dmitriy Y.
Format: Preprint
Published: 2025
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author Shaw, Caleb A.
Anistratov, Dmitriy Y.
author_facet Shaw, Caleb A.
Anistratov, Dmitriy Y.
contents This paper presents a new Monte Carlo (MC) algorithm for time-dependent particle transport problems with global variance reduction based on automatic weight windows (WWs). The centers of WWs at a time step are defined by the solution of an auxiliary hybrid MC / deterministic problem formed by the low-order second-moment (LOSM) equations. The closures for the hybrid LOSM equations are calculated by the MC method. The LOSM equations are discretized by a scheme of the second-order accuracy in time and space. Filtering techniques are applied to reduce noise effects in the LOSM closures. The WWs defined with the auxiliary solution give rise to sufficiently uniform MC particle distribution in space on each time step. The algorithm is analyzed by means of an analytic transport benchmark. We study performance of the MC algorithm depending on a set parameters of WWs. Figure of merit and relative error results are presented, demonstrating the performance of the hybrid MC method and quantifying its computational efficiency.
format Preprint
id arxiv_https___arxiv_org_abs_2512_19925
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Hybrid Weight Window Method for Global Time-Dependent Monte Carlo Particle Transport Calculations
Shaw, Caleb A.
Anistratov, Dmitriy Y.
Numerical Analysis
Computational Physics
This paper presents a new Monte Carlo (MC) algorithm for time-dependent particle transport problems with global variance reduction based on automatic weight windows (WWs). The centers of WWs at a time step are defined by the solution of an auxiliary hybrid MC / deterministic problem formed by the low-order second-moment (LOSM) equations. The closures for the hybrid LOSM equations are calculated by the MC method. The LOSM equations are discretized by a scheme of the second-order accuracy in time and space. Filtering techniques are applied to reduce noise effects in the LOSM closures. The WWs defined with the auxiliary solution give rise to sufficiently uniform MC particle distribution in space on each time step. The algorithm is analyzed by means of an analytic transport benchmark. We study performance of the MC algorithm depending on a set parameters of WWs. Figure of merit and relative error results are presented, demonstrating the performance of the hybrid MC method and quantifying its computational efficiency.
title Hybrid Weight Window Method for Global Time-Dependent Monte Carlo Particle Transport Calculations
topic Numerical Analysis
Computational Physics
url https://arxiv.org/abs/2512.19925