Detection and identification method employing mossbauer isotopes

A method for detecting the presence or absence of an explosive material in a container, the method comprising:

• (a) incorporating in the explosive material a non-radioactive, inert tagging substance comprising a Mossbauer isotope;
• (b) providing nuclear detector means including a Mossbauer isotope-containing detecting substance which is identical to the tagging substance, and sensing means responsive to the presence of said tagging substance in the carrier material, provided that the Mossbauer isotope of said tagging substance is in a state of resonance excitation and causes excitation of the Mossbauer isotope of said detecting substance, said sensing means being operatively associated with indicator means for indicating whether or not said sensing means has sensed radiation emitted from the excited Mossbauer isotope of said detecting substance;
• (c) exposing said container to said detector in position to activate said sensing means;
• and
• (d) irradiating said container with gamma radiation from a radioactive source comprising a Mossbauer isotope-containing substance which corresponds to the tagging substance, said radiation having the exact energy required to cause resonance excitation in the Mossbauer isotope of the tagging substance, if present in said container, whereby gamma radiation is emitted from the excited Mossbauer isotope of said tagging substance;
• excites the nucleus of the Mossbauer isotope in the detecting substance to a radiation emitting state, the radiation emitted by said detecting substance being sensed by said sensing means, thereby indicating the presence or absence of said explosive material in said container.

A method for obtaining identifying information about an object or a group of objects, the method comprising:

• (a) incorporating in each said object or group of objects a given one of a predetermined number of inert identifier taggants embodying an isotope selected from the group consisting of a Mossbauer isotope and a combination of Mossbauer isotopes, no two identifier taggants in said predetermined number being the same;
• (b) providing an index correlating each identifier taggant in said predetermined number with identifying information about the object or group of objects in which each taggant is incorporated;
• (c) providing nuclear detector means, including Mossbauer isotope-containing detecting substances, which are identical and equal in number to the predetermined number of identifier taggants, and sensing means responsive to the presence of an identifier taggant in one of said objects or in a member of said group of objects, provided that each Mossbauer isotope of said identifier taggant is in a state of resonance excitation and causes excitation of each Mossbauer isotope of said detecting substance to which it is identical, said sensing means being operatively associated with indicator means for indicating whether or not said sensing means has sensed radiation emitted from each Mossbauer isotope of said identical detecting substance;
• (d) exposing an object containing an identifier taggant to said detector means in position to activate said sensing means whereby the indicator means of the detector means containing the detecting substance that is identical to said identifier taggant indicates that radiation emitted from said identical detecting substance has been sensed by said sensing means, and identifying information about said object is obtainable from said index.