Experimental determination of the amplitude attenuation coefficient of ultrasound in pure water: A comparison between some pulse techniques

The aim of this paper is to compare the results obtained from three experiments carried out to determine the amplitude attenuation coefficient of bi-distilled degassed water. Pulse techniques were implemented in through transmission and pulse-echo configurations. A pulser device and a function generator were employed to drive transducers of 1 MHz and 5 MHz. In two of the three experiments, a sweep along the ultrasonic propagation path was performed by an electronic positioning system in order to register the decaying amplitude of the ultrasonic beam at several points within the distance between the emitter and the receiver or target. Results were obtained by estimating the exponential function that described the behavior of the far field zone of the radiated ultrasound. Obtained values of the attenuation coefficient did not show concordance with the one defined by literature. Errors related to the discrepancies are presumably associated with the frequencies involved but they have not been completely identified. Nevertheless, experiments yielded successively better results.