| 摘要 |
PROBLEM TO BE SOLVED: To discriminate an object itself by using a decay characteristic of a radiation of the object, even when an identifier set artificially for the object is not able to be displayed on the object itself. SOLUTION: The each object is irradiated with the radiation, and a relation between each irradiation date and hour tn, tn+1, tn+2 and the identifier of the each object is stored in a storage part When the optional object is required to be discriminated after the irradiation of the radiation, radioactivity ax of the object is measured, and the irradiation date and hour are inversely operated based at least on a measured value of the radioactivity, a measured date and hour tx, and a characteristic of a predetermined decay curve for showing a decay of the radioactivity in the object along with the lapse of absolute or relative time after the irradiation. The identifier corresponding to the irradiation date and hour operated reversely is retrieved in the storage part to discriminate the object thereby. |
