Danilov V.N. «On the change in the amplitude of the echo signal recorded by a normal probe from a reflector – an ax symmetrically located flat-bottom hole, depending on the ratio of the radii of the hole and the piezoelectric plate of the probe» Контроль. Диагностика, 27, № 12, с. 27-32 (2024)

Calculations of the amplitude of the echo signal recorded by a round direct converter from a reflector – an ax symmetrically located flat bottom hole in the form of an integral representation of the Fourier-Bessel type have been carried out. The calculation results, with an increase in the ratio of the radii of the piezoelectric plate of the probe and the hole, confirmed the previously established by Prof. I.N. Ermolov the presence of a maximum echo signal in the far zone of the transducer when it is located on the border of the near zone of the reflector. It was found that in the far zone of the transducer, a change in the wave parameter of the piezoelectric plate (the product of the wave number of the longitudinal wave by the radius of the piezoelectric plate) from 10 to 25 practically does not affect the dependence of the amplitude of the echo signal on the ratio of the radii of the hole and the piezoelectric plate of the probe. It is shown that an increase in the ratio of the amplitude of the echo signal at the maximum tends to the limit value – corresponding to the amplitude of the bottom echo for the radius of the hole, much larger than the radius of the piezoelectric plate with an increase in the relative range to the flat bottom hole. Keywords: echo signal maximum, reflector, flat bottom hole, far zone, near zone, normal probe, piezoelectric plate, wave parameter, bottom signal.

Golovanov E.V., Kashin V.V., Gorbachev I.A., Kolesov V.V., Zakharov A.V., Dol'nikov G.G. «Piezoelectric sensors for studying the Moon plasma-dust exosphere» Радиоэлектроника. Наносистемы. Информационные технологии, 16, № 7, с. 829-836 (2024)

The scientific research program of lunar landers includes an experiment involving the study of the dynamics of lunar microparticles and the parameters of the near-surface dust plasma. Near-surface plasma and levitating dust particles form the Moon plasma-dust exosphere. To register the mechanical characteristics of dust microparticles, it is necessary to develop an impact sensor. As a sensitive element for the impact sensor, the shock sensitivity of various piezoelectric materials was experimentally studied: lithium niobate single crystals, PZT-19 piezoceramics, as well as a piezopolymer film of polyvinylidene fluoride. To register electrical signals on the piezoelectric sensors surface, a measuring stand with the original topology of the electrode system on the plates has been developed. The sensitivity of various piezoelectric sensors to impact, the response times of the sensor to impact, as well as the coordinates of the impact points on the sensor plates were measured.