The particle-induced depression of the superconducting critical temperature, T/sub c/, of YBa/sub 2/Cu/sub 3/O/sub 7- delta / is shown to be directly proportional to the nonionizing energy loss (NIEL) of primary knock-on atoms (PKAs) displaced by incident electrons, protons, and heavy ions, which cover a NIEL range of over seven orders of magnitude. Calculations of the NIEL for electrons and protons are given for YBa/sub 2/Cu/sub 3/O/sub 7/ over the range 1-1000 MeV. The partition of NIEL among the elements as a function of incident electron energy is discussed. For a given particle fluence Phi , it is concluded that dT/sub c//d Phi is proportional to the average number of defects produced, is not affected by the formation of defects in cascades, and is independent of the PKA spectrum. This means that the particle-induced depression of T/sub c/ can be predicted for any particle type, for any energy, and for any fluence. >