System and method of migratory animal identification by fluorescence spectroscopy of element coded implanted tags, and tags used therein

The method of tagging a migratory animal with an implanted tag which is coded as to origin, point of release or the like, and subsequently identifying the code of the implanted tag without harm to the animal, said method comprising:

• (a) implanting in the body of the animal an identification tag at least in part including at least one naturally occurring, non-radioactive higher atomic numbered chemical element in stable solid form, each such chemical element serving as a coding element and being present in the amount of at least about 15 micrograms, the chemical element(s) present in the tag providing a coded identification related to the origin, point of release, or the like, characteristic of the animal;
• (b) releasing the animal to its habitat;
• (c) subsequently identifying such animal as being tagged by sensing the presence of the tag within the animal and confining the animal, so identified;
• (d) while the animal is alive, irradiating the tag with an X-ray beam at an energy level higher than the absorption edge of the coding element(s) comprising the tag and at an intensity, disregarding absorptive losses in the animal tissue surrounding the tag, of at least about 3.times.10.sup.10 photons/cm.sup.2 -sec;
• (e) masking all but the tag and the animal tissue immediately surrounding the tag from irradiation by the X-ray beam;
• (f) determining the extent of fluorescent X-ray radiation emitted by the coding element(s) in the tag and from such determination identifying the coding element(s) present in the tag and thus the code thereof;
• and
• (g) subsequently releasing the live animal to its habitat.

A system for identifying by X-ray fluorescence analysis any higher atomic numbered chemical elements present as coding elements in a tag implanted for a time in the body of a migratory animal, said system comprising:

• (a) an X-ray generator and X-ray beam delivery means producing a beam of X-rays of an energy higher than the absorption edge of the fluorescent X-ray radiation of any coding element(s) in the tag, and of an intensity, disregarding absorptive losses in any animal tissue surrounding the tag, of at least about 3.times.10.sup.10 protons/cm.sup.2 -sec;
• (b) a system for precisely locating the tag and irradiating the tag with such X-ray beam, and including masking means providing that only the tag and a minimal amount of any animal tissue immediately surrounding the tag are irradiated by the X-ray beam;
• (c) energy dispersive X-ray detector means sensitive to the characteristic fluorescent X-ray radiation radiated by any coding element(s) in the tag during irradiation thereof;
• and
• (d) multi-channel analyzer means determining from the radiation detected by said detector means the energy spectrum of the fluorescent X-ray radiation emitted by any coding element(s) in the tag, and thus identifying such coding element(s).

A system for rapidly identifying by X-ray fluorescence analysis any higher atomic numbered chemical elements present as coding elements in an identification tag implanted for a time in the body of a live migratory animal, said system comprising:

• (a) means for retaining the live animal substantially immobile and in position for radiographic imaging of the tag and for irradiation of the tag by a narrowly defined beam of X-rays;
• (b) X-ray generator and X-ray beam delivery means producing a beam of X-rays of an energy higher than the absorption edge of the fluorescent X-ray radiation of any coding element(s) in the tag, and of an intensity, disregarding absorptive losses in any animal tissue surrounding the tag, of at least about 3.times.10.sup.10 photons/cm.sup.2 -sec;
• (c) a system for precisely locating the tag and irradiating the tag with such X-ray beam, and including masking means providing that only the tag and the animal tissue immediately surrounding the tag and in alignment with the X-ray beam axis are irradiated by the X-ray beam;
• (d) energy dispersive X-ray detector means sensitive to the characteristic fluorescent X-ray radiation radiated by any coding element(s) in the tag during irradiation thereof;
• and
• (e) multi-channel analyzer means determining from the radiation detected by said detector means the energy spectrum of the fluorescent X-ray radiation emitted by any coding element(s) in the tag, and thus identifying such coding element(s).