Theory and generation methods for N-ary stochastic mixtures with Markovian mixing statistics.
Abstract not provided.
Olson, Aaron↗
Engineering topics
Pautz, Shawn
Publications and source records attributed to Pautz, Shawn.
Algorithms and Applications of the SCEPTRE Radiation Transport Code.
Abstract not provided.
Pautz, Shawn↗
SCEPTRE v. 2.0 (Sandia Computational Engine for Particle Transport for Radiat
SCEPTRE solves the linear Boltzmann transport equation for general one-, two- and three-dimensional unstructured-mesh Cartesian geometries. SCEPTRE can handle any particle type for which multigroup-Legendre cross sections are available. However, the code is designed primarily to model the transport of photons, electrons, and positrons through matter. SCEPTRE 2.0 includes several auxiliary packages for pre- and post-processing, regression testing, stochastic radiation transport, thermal radiation transport, and charged-particle transport in the presence of electromagnetic fields. SCEPTRE 2.0 includes sophisticated transport-synthetic acceleration and ray-effects mitigation capabilities.
Pautz, Shawn↗
Adjoint-enabled multidimensional optimization of satellite electron/proton shields - 25452
The design of satellites usually includes the objective of minimizing mass due to high launch costs, which is complicated by the need to protect sensitive electronics from the space radiation environment. There is growing interest in automated design optimization techniques to help achieve that objective. Traditional optimization approaches that rely exclusively on response functions (e.g. dose calculations) can be quite expensive when applied to transport problems. Previously we showed how adjoint-based transport sensitivities used in conjunction with gradient-based optimization algorithms can be quite effective in designing mass-efficient electron/proton shields in one-dimensional slab geometries. In this paper we extend that work to two-dimensional Cartesian geometries. This consists primarily of deriving the sensitivities to geometric changes, given a particular prescription for parameterizing the shield geometry. We incorporate these sensitivities into our optimization process and demonstrate their effectiveness in such design calculations. (authors)
42 ENGINEERING↗
Specializations in the SCEPTRE code for charged-particle transport - 25454
Charged particles present some unique challenges for radiation transport codes. This is because charged particles have cross sections that are extremely forward peaked, are huge in the limit of small energy transfer, and are highly scattering, which causes slow convergence of the source iterations. The primary application of SCEPTRE is modeling radiation-driven electrical effects, so substantial effort has been invested in SCEPTRE for the efficient modeling of electron transport. This paper will summarize recent and ongoing activities involving the accurate deterministic-transport modeling of charged particles and methods implemented to improve iterative convergence. (authors)
61 RADIATION PROTECTION AND DOSIMETRY↗
radlibTests v. 1.0
Suite of scripts for performing regression testing of the SCEPTRE radiation transport code, include MMS testing and mesh-convergence analyses
Fan, Wesley↗
radNuGET v. 1.0
Postprocessing tools to map from 3D Cartesian angular fluence from SCEPTRE to 1D spherical geometry data for NuGET
Pautz, Shawn↗