Abstract
Energy relaxation processes after the passage of fast heavy ions through YBa2 Cu3 O7−δ single crystal have been calculated. Effective times τ of electron-atom energy relaxation have been determined as fitting parameters for each pair of the measured track radius and the value of dE/dx. The latter quantity has been chosen over the interval of 20 ÷ 40 keV/nm. The calculated results are compared with short pulse laser experiments and with Allen's theory, which predicts almost a linear dependence of τ on electron temperature.