ISSN: 1546-962X
Page Count: 10

Coarse-Mesh Adjoint Biasing of a Monte Carlo Dose Calculation

Pevey, RE
The University of Tennessee,TN,

Miller, LF
The University of Tennessee,TN,

Marshall, WJ
The University of Tennessee,TN,

Townsend, LW
The University of Tennessee,TN,

Alvord, B
CTI, Inc.,TN,

(Received 20 June 2005; accepted 19 April 2006)

Abstract

Deep penetration radiation transport calculations have been performed to determine the dose rates at a positron emission tomography (PET) facility in China. The radiation source is a cyclotron that is used for the production of the PET isotopes, with a labyrinthine concrete wall arrangement to minimize dose to operation personnel. Since directionally biased Monte Carlo calculations did not reach an acceptably low standard error after a week of CPU time, approximate adjoint fluxes were calculated for each of four detector locations using coarse-mesh adjoint discrete ordinates calculations and were used to bias the Monte Carlo calculations. This biasing resulted in improved computational efficiency of a factor of one to three orders of magnitude. This result shows the value of even approximate adjoint flux biasing to speed up Monte Carlo calculations.

Keywords:
isotope production, Monte Carlo, discrete ordinates, adjoint biasing

Paper ID: JAI13488
DOI: 10.1520/JAI13488
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