[en] We report the development of a hybrid analytic/Monte Carlo code for evaluating particle transport in solids. Atomic concentrations in the near surface implanted region of a target material /N/sub k/(x,t)/, are propagated by the code in time through the previously described method of equivalent atomic stopping (MEAS). Implantation source profiles /P/sub k/(x,t)/ are obtained for the initial target composition with the TRIM code (TRI), and propagated in time along with the /N/sub K/(x,t)/ by MEAS. TRIM is also invoked periodically to provide updated profiles /P/sub k/(x,t)/, since the MEAS procedure includes only first order corrections to the /P/sub k// due to the evolution of the /N/sub k//. The code provides for simultaneous implantation of several different atomic species and includes the local mixing model (LMM) for describing buildup to saturation and isotope exchange for implantation of hydrogen (and/or other species). 12 refs., 1 fig