Powder vibration studied by Mössbauer spectroscopy

Abstract

Mössbauer spectroscopy is applied to study ultrasound vibration of a granular material. A pile of powder is placed onto the surface of piezo transducer vibrated with the frequency 12.68 MHz. The size of grains (1.3 µm) is much smaller than the wavelength of ultrasound, but much larger than the vibration amplitude. Due to vibration a single line of the Mössbauer transmission spectrum is split into a comb structure with a period equal to the vibration frequency. This spectrum contains the information about fast and slow modes in granular dynamics. We developed a method which allows to measure decay of ultrasound in the granular material and to estimate the results of the particle convection of grains in the pile.