Internal Friction and Velocity Measurements at Audio-Frequencies in Neutron-Irradiated Quartz

Abstract

The internal friction and the change of the sound velocity of two neutron-irradiated quartz samples was measured at about 1 kHz as a function of the temperature. The behaviour of both the internal friction and the velocity can be explained in the framework of the tunnelling model. The observations demonstrate the validity of the distribution of relaxation times of the TS proposed by the tunnelling model in the region of long relaxation times: 2×10-7≦τ-1/τm -1≦5×10-3.