An Experimental Design for Measuring In Situ Radiation Damage to a Piezoelectric Transducer

An experiment was conducted investigating the use of an acoustic pulse waveguide to collect response measurements from three piezoelectric acoustic emission (AE) transducers while the transducers were exposed to an active nuclear reactor neutron flux ranging from 1 x 1011 to 2.4 x 1012 neutrons per sq cms. Material, mechanical, and radiation studies were performed to determine a practical design for the construction of the experiment. Discreet frequency pulses generated by an Arbitrary Waveform Generator were transmitted by an aluminum waveguide to the core of the Ohio State University Research Reactor (OSURR). Three AF transducers coupled to the waveguide were exposed to the reactor neutron fluence and their response to each frequency pulse was measured over time. The recorded data was used to study the correlation between the neutron dose and resulting device damage. Response measurements were also taken in situ during post-irradiation periods to determine if response changes due to radiation damage would recover with time. Data sampling of transducer response was reproducible with a standard deviation that ranged between 3% and 8% of the mean value for all frequencies. Final transducer response levels varied between devices and frequencies, but were consistently degraded. Decreases in response between transducers ranged from 36% to 78% using the average percent decrease over ten test frequencies. Individual frequency response degradation ranged from 16% to 92%