Thermal annealing effects on silicon surface barrier nuclear detectors damaged with radiation are investigated by measuring output rise time and induced defect densities. Silicon wafers as materials of the detectors are irradiated with gamma-rays of 60-Co, and then the irradiated silicon specimens are annealed thermally. The rise time measurement for 241-Am alpha-particles incidence is performed by using a digital system. It is observed that the rise time of the annealed detectors becomes faster than that of the irradiated detectors. The induced defect densities, measured with DLTS method, are reduced to about 1/2 the amount of irradiated detectors, for annealing temperature 420K, 60 minutes. The characteristics of the detectors irradiated with less than l??107R are almost recovered in accordance with the decrease of defect densities.
