Calculations of Dose Enhancement in Device Structures

Using a semi-empirical electron transport model and the solution of the one-group S2 transport equation for a multilayered system, a fast algorithm has been developed for calculating X-ray dose enhancement in device structures. The program MULTI-LAYER, written in BASIC for an IBM-PC compatible microcomputer, calculates (1) the dose profile across a multilayered structure, including electron transport, (2) the absorbed dose neglecting electron transport and (3) the ratio of these two quantities--the "dose enhancement" profile. The dose as a function of position can be found for a structure with one to ten layers. MULTILAYER uses monoenergetic photons and is valid over the 100-1250 keV photon energy range. The output compares well with much longer electron Monte Carlo and discrete-ordinates transport calculation. Results are given for an Al/Au multilayered structure. Examples of Al are given. Graphs. 9 ref.--AA(UK).