Quantum Monte Carlo (QMC) methods such as Variational Monte Carlo, Diffusion Monte Carlo or Path Integral Monte Carlo are the most accurate and general methods for computing total electronic energies. We will review methods we have developed to perform QMC for the electrons coupled to another MC simulation for the ions. In this method, one estimates the Born-Oppenheimer energy E(Z) where Z repr...

The Monte Carlo method is often referred to as a ‘computer experiment’. One might think of this as a way of conveying the fact that the output of simulations is not an equation, as in conventional theory. Instead, numbers appear on the computer screen in somewhat the same way that numbers appear on a measuring device in the laboratory. Thus there is the implication that somehow simulations are ...

Introduction Proton therapy is used to treat malignant tumors such as melanoma inside the eye. Proton particles are adjusted according to various parameters such as tumor size and position and patient’s distance from the proton source. The purpose of this study was to assess absorbed doses in eyes and various tumors found in the area of sclera and choroid and the adjacent tissues in radiotherap...

ABSTRACT Background: accurate methods of radiation therapy dose calculation. There are different Monte Carlo codesfor simulation of photons, electrons and the coupled transport of electrons and photons. MCNPis a general purpose Monte Carlo code that can be used for electron, photon and coupledphoton-electron transport.Monte Carlo simulation of radiation transport is considered to be one of the ...

In the radiotherapy (RT) of moving targets with scanned ion-beams at GSI we are investigating a new method of fast range adaptation. The method controls an ion-beam depth in a moving target by deflecting the ion-beam on an appropriate thickness of a static wedge shaped energy degrader placed upstream in the ion-optical system. A feasibility study of this method using Monte Carlo simulations are...

this paper investigates the radiative absorptivity of a spherical cavity by using monte carlo techniques. several parameters such as the angle of incoming radiation which inters the cavity for both diffuse wall cavity and specular wall cavity has been  investigated. the absorptivity of a spherical cavity has been calculated and compared with the exact values when the angle of incoming radiation...

Objective(s): Normoxic MAGIC-f polymer gels are established dosimeters used for three dimensional dose quantifications in radiotherapy. Nanoparticles with high atomic number such as gold are novel radiosensitizers used to enhance doses delivered to tumors. The aim of this study was to investigate the effect of gold nanoparticles (GNPs) in enhancing percentage depth doses (PDDs) within the MAGIC...

In this paper, we apply a mixed Monte Carlo and Quasi-Monte Carlo method, which we proposed in a previous paper, to problems from mathematical finance. We estimate the value of an European Call option and of an Asian option using our mixed method, under different horizont times. We assume that the stock price of the underlaying asset S = S(t) is driven by a Lévy process L(t). We compare our est...

This paper surveys recent research on using Monte Carlo techniques to improve quasi-Monte Carlo techniques. Randomized quasi-Monte Carlo methods provide a basis for error estimation. They have, in the special case of scrambled nets, also been observed to improve accuracy. Finally through Latin supercube sampling it is possible to use Monte Carlo methods to extend quasi-Monte Carlo methods to hi...

RapidArc radiotherapy technology from Varian Medical Systems is one of the most complex delivery systems currently available, and achieves an entire intensity-modulated radiation therapy (IMRT) treatment in a single gantry rotation about the patient. Three dynamic parameters can be continuously varied to create IMRT dose distributions-the speed of rotation, beam shaping aperture and delivery do...