Time development and flux dependence of neutron-irradiation induced defects in silicon pad detectors

1 x 1 cm(2) silicon pad p(+)-n-n(+) detectors were irradiated with fast neutrons from the TRIGA research reactor in Ljubljana to fluences from 5 x 10(13) to 10(14) n/cm(2). The observed time development of annealing of the full-depletion voltage (FDV) could be fitted by a constant and two exponentials. The characteristic time of the fast component is 4 h, independent of temperature in the interval 0-15 degrees C. A comparison of MESA and planar pad detectors shows a 20-30% lower FDV for the MESA. A search for a flux dependence of the radiation damage was performed in the range from 2 x 10(8) to 5 x 10(15) n/cm(2)s and no systematic differences were observed. (C) 1999 Elsevier Science B.V. All rights reserved.