The hybrid model for sampling multiple elastic scattering angular deflections based on Goudsmit-Saunderson theory

• Published in: Nuclear technology & radiation protection Vol. 32; no. 3; pp. 229 - 235
• Main Authors: Wasaye, Muhammad, Wang, Hui, Zheng, Huaqing, Long, Pengcheng, Naeem, Hamza
• Format: Journal Article
• Language: English
• Published: Belgrade Vinca Institute of Nuclear Sciences 01-01-2017; VINCA Institute of Nuclear Sciences
• Subjects: Algorithms; Angular distribution; Computer simulation; differential cross-section; Distribution functions; Elastic scattering; Electrons; ELSEPA; Goudsmit-Saunderson; Monte Carlo; Monte Carlo simulation; multiple scattering; Neutral atoms; Positrons; Rejection; Sampling; SuperMC
• ISSN: 1451-3994; 1452-8185
• DOI: 10.2298/NTRP1703229W

An algorithm for the Monte Carlo simulation of electron multiple elastic
scattering based on the framework of SuperMC (Super Monte Carlo simulation
program for nuclear and radiation process) is presented. This paper describes
efficient and accurate methods by which the multiple scattering angular
deflections are sampled. The Goudsmit-Saunderson theory of multiple
scattering has been used for sampling angular deflections. Differential
cross-sections of electrons and positrons by neutral atoms have been
calculated by using Dirac partial wave program ELSEPA. The Legendre
coefficients are accurately computed by using the Gauss-Legendre integration
method. Finally, a novel hybrid method for sampling angular distribution has
been developed. The model uses efficient rejection sampling method for low
energy electrons (<500 keV) and larger path lengths (>500 mean free paths).
For small path lengths, a simple, efficient and accurate analytical
distribution function has been proposed. The later uses adjustable parameters
determined from the fitting of Goudsmith-Saunderson angular distribution. A
discussion of the sampling efficiency and accuracy of this newly developed
algorithm is given. The efficiency of rejection sampling algorithm is at
least 50 % for electron kinetic energies less than 500 keV and longer path
lengths (>500 mean free paths). Monte Carlo Simulation results are then
compared with measured angular distributions of Ross et al. The comparison
shows that our results are in good agreement with experimental measurements.
nema