A rotating sample cell for in situ measurements of adsorption with x-rays

A sample cell which facilitates adsorption in conjunction with small angle x-ray scattering under a rotational field is presented. The device allows dynamic phenomena that take place within a pore system to be investigated in situ by x-rays. As an example, a sample of Vycor porous glass was measured at relative pressures p/p_o = 0 and p/p_o = 0.5. For the static measurements, the results were as expected. Under rotation, an increase in the scattered intensity of the loaded sample, over the corresponding static one, is observed. Fractal analysis has shown an increase in the fractal dimension even higher than that of the dry sample. It was suggested that the increase in the scattered intensity was due to the rotation, while the abnormality in the fractal dimension was due to asymmetric ripples of the adsorbed layers. The limits of the technique are given too.