A method of checking the storage and the radioactive activity of a radioactive gas adsorbed by a porous material having scintillation properties, which comprises: (a) putting the porous material in place in an enclosure, (b) performing circulation of the radioactive gas in the enclosure, (c) monitoring the adsorption of the radioactive gas by monitoring the scintillation of the porous material, up to an adsorption level, (d) interrupting the radioactive gas circulation in the enclosure when the adsorption level is attained, (e) placing the enclosure under a vacuum, and (f) monitoring the radioactive activity of the radioactive gas adsorbed by the porous material at the end of step (c) by monitoring the scintillation of the porous material. The porous material comprises metal organic frameworks formed of inorganic sub-units constituted by Zn.sub.4O and an organic ligand.