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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