Solar particle event dose and dose-rate distributions: parameterization of dose-time profiles, with subsequent dose-rate analysis.

Calculations of total dose and equivalent dose as functions of time, as well as dose-rate and equivalent dose rate since event start are presented for fifteen of the larger solar particle events that occurred during the period between November 1987 and August 1991. The doses, dose-equivalents, and rates presented are for exposures to the skin, ocular lens, and bone marrow behind a thickness of aluminum shielding which provides protection comparable to that of a thin spacecraft. The calculated dose vs time profiles are parameterized using a Weibull cumulative distribution as the fitting function. Parameters are determined using least-squares techniques. Fitted curves are then differentiated to produce smoothed dose-rate curves for each of the events. These results provide a useful starting point for the development of methods to predict the cumulative doses and times to reach various dose limits from a limited number of dosimeter measurements early in the evolution of a solar particle event.