Powder vibration studied by Mössbauer spectroscopy

英文摘要：

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 $μ$m) 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.