POS-SPRITE - AN EXTENSIBLE CALCULATION OF POSITRON AND ELECTRON IMPLANTATION IN METALS

Accurately modeling the behavior of a beam of positrons incident upon a solid is of crucial importance for depth-profiling and data analysis in slow positron experiments. We describe a suite of Fortran programs to perform a Monte Carlo calculation of positron implantation in amor phous metals and small bandgap semiconductors. This provides statistic al information about penetration (stopping profiles, thermalization ti me, etc.), energy loss and reemission (backscattering, thin film trans mission, etc.), The calculation is implemented using a user-friendly M onte Carlo transport ''engine'', which is capable of treating particle transport in infinite, semi-infinite, and multilayer systems. A conti ngent of elastic (up to 10 keV) and inelastic (down to 30 eV) scatteri ng mechanisms is included, but different mechanisms can be added via e xternal data files or code modification. As a consequence of the scatt ering theory involved, this calculation is amenable to electron implan tation and scattering. (C) 1998 Elsevier Science B.V.