  Investigation of dynamics in dense granular media is challenging. Here we
present a setup that facilitates gas fluidization of dense granular media in
microgravity. The dynamics is characterized using diffusing wave spectroscopy.
We demonstrate that agitated granular media reach a steady state within
fractions of a second in drop tower flights. The intensity autocorrelation
functions obtained in microgravity show a remarkable dependence on sample
volume fraction and driving strength. A plateau in correlation merges at low
volume fractions and strong driving, while correlation decays only very slowly
but continuously at high packing fractions. The setup allows to independently
set sample volume fraction and driving strength, and thus extends the
possibilities for investigations on dynamics in dense granular on ground.
