ECAM Institut Supérieur Industriel

Brachytherapy is a radiotherapy treatment where encapsulated radioactive sources are introduced within a patient. Depending on the technique used, such sources can produce high, medium or low local dose rates. The Monte Carlo method is a powerful tool to simulate sources and devices in order to help physicists in treatment planning. In multiple types of gynaecological cancer, intracavitary brachytherapy (HDR Ir-192 source) is used combined with other therapy treatment to give an additional local dose to the tumour. Different types of applicators are used in order to increase the dose imparted to the tumour and to limit the effect on healthy surrounding tissues. The aim of this work is to model both applicator and HDR source in order to evaluate the dose at a reference point as well as the effect of the materials constituting the applicators on the near field dose. The MCNP5 code based on the Monte Carlo method has been used for the simulation. Dose calculations have been performed with *F8 energy deposition tally, taking into account photons and electrons. Results from simulation have been compared with experimental in-phantom dose measurements. Differences between calculations and measurements are lower than 5%.The importance of the source position has been underlined.

Abstract Micro‐Raman spectroscopic analysis of different species of copper sulfates was carried out. Products such as antlerite, brochantite, posnjakite, langite and chalcanthite were investigated. These products are most likely to be formed as the result of atmospheric corrosion of copper alloys, e.g. bronze in sulfur‐bearing environments. A database containing the characteristic Raman spectra was set up. This database was then used to investigate some specimens of copper alloy artefacts, that had been exposed to the atmosphere. It was shown to be possible to identify the nature of the corrosion products formed, using micro‐Raman spectroscopy. Copyright © 2004 John Wiley & Sons, Ltd.

Multilayer solutions that calculate stresses, strains, and displacements in pavement structures caused by surface loading have been in existence for several years. However, most elastic layer computer software applications have been developed for mainframe computers. Recently, computational capabilities of the practicing engineer have been greatly enhanced by recent developments in personal computers. Results of this study involved development of an accurate and efficient solution to the multilayer problem. In addition, software was developed for use on a personal computer that included routines for backcalculating pavement layer moduli from measured surface deflections. A convergence technique, employing a combination of closed form and numerical solutions, has been developed to provide accuracy of results at the surface of the pavement and near the load. Special methods of solving the system of boundary equations were developed to obtain the terms needed for the closed form part of the solution. Maximum efficiency has been obtained through an in-depth analysis of the parameters affecting accuracy and their relationship with the numerical integration step. In its current form, the computer solution WESLEA is a fully competent three-dimensional solution that will handle up to five layers with varying interface conditions and a maximum of 20 loads. The fifth layer is semi-infinite and can be made stiff based on the choice of modulus of elasticity. A personal computer-based backcalculation program, WESDEF, has been developed utilizing the multilayer program. An evaluation of the new program is made through comparison of identical deflection data using the BISAR n-layered computer program.