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Drumm, Clif

Publications and source records attributed to Drumm, Clif.

5 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

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↗
DOE OSTI2017

radNuGET v. 1.0

Postprocessing tools to map from 3D Cartesian angular fluence from SCEPTRE to 1D spherical geometry data for NuGET

Pautz, Shawn↗
DOE OSTI2017

radlibEM

Perform charged-particle radiation transport in the presence of electric and magnetic fields

Fan, Wesley↗
DOE OSTI2017

Multilevel acceleration of scattering-source iterations with application to electron transport

Acceleration/preconditioning strategies available in the SCEPTRE radiation transport code are described. A flexible transport synthetic acceleration (TSA) algorithm that uses a low-order discrete-ordinates (S N ) or spherical-harmonics (P N ) solve to accelerate convergence of a high-order S N source-iteration (SI) solve is described. Convergence of the low-order solves can be further accelerated by applying off-the-shelf incomplete-factorization or algebraic-multigrid methods. Also available is an algorithm that uses a generalized minimum residual (GMRES) iterative method rather than SI for convergence, using a parallel sweep-based solver to build up a Krylov subspace. TSA has been applied as a preconditioner to accelerate the convergence of the GMRES iterations. The methods are applied to several problems involving electron transport and problems with artificial cross sections with large scattering ratios. These methods were compared and evaluated by considering material discontinuities and scattering anisotropy. Observed accelerations obtained are highly problem dependent, but speedup factors around 10 have been observed in typical applications.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗