Episodes of Solar Energetic Proton Flux Since 1973

We have compiled a record containing all the episodes of elevated solar proton fluxes since 1973 by combining data from the Goddard Medium Energy instrument on IMP-8 before November 2001 with data from the EPS and HEPAD instruments on several GOES satellites since October, 2001. The methods used to prepare the data set and the proton differential energy spectra of the episode-integrated fluences will be described. Results will be presented on the solar cycle dependence of the episode frequency. The cumulative distributions of episode-integrated proton fluences in energy bands from 1 to 700 MeV and their variation with solar cycle will be presented. The implications of these results for radiation protection of space crews will be discussed.