S. T. Perkins

Single-scatter Monte Carlo compared to condensed history results for low energy electrons *

Abstract A Monte Carlo code has been developed to simulate individual electron interactions. The code has been instrumental in determining the range of validity for the widely used condensed history method. This task was accomplished by isolating and testing the condensed history assumptions. The results show that the condensed history method fails for low energy electron transport due to inaccuracies in energy loss and spatial positioning.

Photon and electron data bases and their use in radiation transport calculations

Abstract The ENDF/B-VI photon interaction library includes data to describe the interaction of photons with the elements Z = 1–100 over the energy range 10eV–100MeV. This library has been designed to meet the traditional needs of users to model the interaction and transport of primary photons. However, this library contains additional information which, used in a combination with our other data libraries, can be used to perform much more detailed calculations, e.g. emission of secondary fluorescence photons. This paper describes both traditional and more detailed uses of this library.

The All Particle Monte Carlo Method: 1990 Status Report

Abstract Development of the All Particle Method, a project to simulate the transport of particles via the Monte Carlo method, has proceeded on two fronts: data collection and algorithm development. In this paper we report on the status of both these aspects. The data collection is nearly complete with the addition of electron and atomic data libraries and a newly revised photon library to the existing neutron and charged particle libraries. We describe the basic organization of the Monte Carlo computer code that will actually perform the simulation. Algorithm development has proceeded less quickly than the data portion of the project. The new Response Matrix Monte Carlo method is summarized and some numerical results presented.

An exact benchmark calculation for l'th mode multigroup transfer matrix analysis

There are few exact numerical solutions to which results from multigroup transfer matrix algorithms can be compared. Therefore, for isotropic elastic scattering in the centerof-mass system, exact numerical values have been calculated for P /SUB l/ (..mu..), 0 less than or equal to 1 less than or equal to 20, the average Legendre coefficient of the scattered particle in the laboratory system. Both projectile and target masses are allowed to vary between 1 and 238 amu. It can be concluded that significant numerical uncertainties are possible in the calculation of the higher order transfer matrices. Exact numerical values have been obtained for the average Legendre coefficient in the L system, P /SUB l/ (..mu..), under the condition that the CM angular distribution is isotropic. These results should serve as a tool for debugging new multigroup transfer matrix subroutines and should also be helpful for determining the accuracy of all such algorithms.