Time-averaged image (exposition 0.8 s) (a), differential image (b)
Temporal evolution of the spatially averaged brightness of differential
images for various values of the pressure drop 31.3 kPa(a), 32.9 kPa (b),
34.1kPa (c), and 35.6 kPa (d)
Characteristic bed relaxation time and differential image brightness
vs pressure drop