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Title: Angular quadrature sets for the streaming ray method in x-y geometry

Journal Article · · Nucl. Sci. Eng.; (United States)
OSTI ID:5502136

Steaming ray (SR) computations normally employ a set of specially selected ray directions. For x-y geometry, these directions are not uniformly spaced in the azimuthal angle, nor do they conform to any of the standard quadrature sets in current use. For simplicity in all previous SR computations, uniform angular weights were used. This note investigates two methods--a bisection scheme and a Fourier scheme--for selecting more appropriate azimuthal angular weights. In the bisection scheme, the azimuthal weight assigned to an SR direction is half the angular spread (in the x-y plane) between its two adjacent ray directions. In the Fourier method, the weights are chosen such that the number of terms in a Fourier series exactly integrable on the interval (0, 2..pi..) is maximized. Several sample calculations have been performed. While both the Fourier and bisection weights showed significant advantage over the uniform weights used previously, the Fourier scheme appears to be the best method. Lists of bisection and Fourier weights are given for quadrature sets containing 4, 8, 12, ..., 60 azimuthal SR directions.

Research Organization:
Universidad Nacional Autonoma de Mexico Apdo, Postal 20-726, 01000
OSTI ID:
5502136
Journal Information:
Nucl. Sci. Eng.; (United States), Vol. 83:4
Country of Publication:
United States
Language:
English