Experimental Search for Avalanches of Entangled Dislocations as a Source of Dissipation and Mechanical Noise

Recent measurements using highly sensitive instruments have shown increased dissipation and the appearance of random low frequency noise in metal flexures. These effects have been attributed to avalanches of dislocations, a phenomenon supposedly controlled by self-organized criticality (SOC) statistics. This experiment is attempting to detect these subtle effects using a variation on the rotating beam Kimball-Lovell 1927 experiment that was used to measure the loss angle of materials above 1Hz. We have demonstrated the feasibility of making measurements of loss angle with μ-radian precision at arbitrarily low frequencies. If dislocation avalanches are the source of the 1/f noise in these flexures, we expect to see them using this experiment.