AIM The aim of this work was to develop multiple-source models for electron beams of the NEPTUN 10PC medical linear accelerator using the BEAMDP computer code. BACKGROUND One of the most accurate techniques of radiotherapy dose calculation is the Monte Carlo (MC) simulation of radiation transport, which requires detailed information of the beam in the form of a phase-space file. The computing...

We describe a semi-analytical method for the fast calculation of secondary fluorescence in electron probe microanalysis of material couples. The calculation includes contributions from primary K-, Land M-shell characteristic x-rays and bremsstrahlung photons. The required physical interaction parameters (subshell partial cross sections, attenuation coefficients, etc) are extracted from the data...

Monte Carlo shielding analysis capabilities in SCALE 6 are centered on the Consistent Adjoint Driven Importance Sampling (CADIS) methodology. CADIS is used to create an importance map for space/energy weight windows as well as a biased source distribution. New to SCALE 6 are the Monaco functional module, a multigroup fixed-source Monte Carlo transport code, and the Monaco with Automated Varianc...

AIM The Monte Carlo dose calculation algorithm yields accurate dose distributions in heterogeneous media and interfaces. The Monte Carlo calculation algorithm provided in the Multiplan Cyberknife treatment planning system (Accuray, Sunnyvale, CA, USA) has five different dose-smoothing algorithms in it. As the principle of smoothing of these algorithms is different, they can produce a disparity ...

Correlated sampling technique has been applied to the ssion matrix approach for Monte Carlo eigenvalue calculation of reactivities ((K) due to small cross-section perturbations. The reference Monte Carlo simulation is performed in a system diierent from both the unperturbed and perturbed systems. This allows the determination of multiple Ks due to multiple cross-section perturbations with a sin...

Algorithms are presented which advance the state of the art in Monte Carlo device simulation in two ways. Firstly, a method of free-flight time calculation using a new self-scattering algorithm is described. A piecewise linear total scattering rate allows for an efficient reduction of self-scattering events. Secondly, a unique Monte Carlo-Poisson coupling scheme is adopted, which converges fast...

Monte Carlo codes are utilized for accurate dose calculations in proton radiation therapy research. While they are superior in accuracy to commonly used analytical dose calculations, they require significantly longer computation times. The aim of this work is to characterize a Monte Carlo track-repeating algorithm to increase computation speed without compromising dosimetric accuracy. The track...

Transition probabilities governing the interaction of energy packets and matter are derived that allow Monte Carlo NLTE transfer codes to be constructed without simplifying the treatment of line formation. These probabilities are such that the Monte Carlo calculation asymptotically recovers the local emissivity of a gas in statistical and radiative equilibrium. Numerical experiments with one-po...

The connection between analytic and Monte Carlo calculations of soft gluon emission is reanalyzed in light of recent, theoretical developments in resummation. An alternative Monte Carlo algorithm is suggested which incorporates (1) corrections beyond leading order to the showering and (2) smoothly merges with the higher order calculation of single, hard parton emission. In particular, it is pos...