Sources of Dose Variability and a Dose Prediction Model Benchmark for Low Energy Electron Beams

摘要

In this PowerPoint presentation, the types of dose variability observed in a low voltage electron beam are characterized. Sharp gradients at low voltage make direct measurement of the true surface dose (first micron) difficult since the thin film dosimeters that must be used capture a gradient dose that represents only an average through a thickness of at least 10 microns. A method for calculating a surface dose at low voltage is illustrated using a model of the problem and Monte Carlo code (ITS). Such model predictions must always be benchmarked against dosimetry. This brings into play a variety of issues associated with dosimetry measurement, model building and the characteristics of a specific piece of equipment that all must come together in order to achieve agreement. This is demonstrated using an example to illustrate the value that these predictions provide when operating at voltages in the range of 80-120kV.