“…Due to its improved data acquisition rate compared to other three-dimensional imaging methods [58] such as x-ray CT [147], RIMS [148] or PET [149], and its improved spatial resolution as compared to radioactive particle tracking [150] or magnetic particle tracking [151], PEPT has proved a highly popular means of studying the dynamics of granular gases [152], whose rapid dynamics researchers could not previously capture precisely using conventional techniques. Granular gases, and more generally 'vibrofluidised' granular beds [153], provide a valuable canonical system in which to study the fundamental phenomena and dynamics of particulate media [58], making them a common choice for such pure-physics studies. PEPT has been used to study numerous aspects of these systems, including their granular temperature distributions [154] (and the striking non-equipartition thereof [2,155]), their diffusive behaviours [32,156], their velocity distributions [33,157], and phenomena such as jamming [158], segregation [3], and granular convection [1,4].…”