We propose an improved method for the analysis of Thermally Stimulated Currents (TSC) measured on highly irradiated silicon diodes. The proposed TSC formula for the evaluation of a set of TSC spectra obtained with different reverse biases leads not only to the concentration of electron and hole traps visible in the spectra but also gives an estimation for the concentration of defects which not give rise to a peak in the 30220K TSC temperature range (very shallow or very deep levels). The method is applied to a diode irradiated with a neutron fluence of fn ¼ 1:82 1013 n/cm2.