Experimental analysis of ultrasound vibrations induced in solids

The phenomenon of ultrasound vibration of cylindrical solid specimen is investigated experimentally. Vibration is induced by means of an ultrasound piezoelectric transducer with 20 kHz working frequency. Brittle Luserna stone resonant samples are considered, in addition to Schorl crystals (black tourmaline). The phenomenon is characterized from a dynamical point of view acquiring the vibration spectrum of the specimens by means of a laser source acquired by a photodiode. The complete surface temperature of the vibrating sample is acquired at time intervals with a digital thermo-camera. The emission of neutrons is monitored with He3 devices and bubble detectors, and is compared to the background level. Finally, the consumed energy that is input in the system is monitored. A preliminary, yet conservative estimation of the energy balance suggest the existence of some extra energy to justify the overheating of the sample during the test. This phenomenon could be reasonably relate to the measured neutron emissions, and could be relevant to some technical applications.