Detectability of Rare Earth Elements in Explosive Post Blast Residues by Neutron Activation Analysis for use as Identification Taggants

Abstract

Current identification techniques can only identify the type of explosive used from traces in the post-blast residue. An identification taggant is a material added to an explosive that can provide identifying information about the explosive such as manufacturer, type, or date the explosive was produced. A novel identification taggant named the Nuclear Barcode is proposed, where specific elements in various concentrations allow up to 6.56 trillion different variations of the barcode. Holmium, samarium, and europium were chosen as taggant elements for initial testing purposes, the results of which are presented herein. Aqueous solutions and explosive post-blast residue where one or more taggant elements were added to the undetonated explosive were analyzed. Neutron activation analysis (NAA) was utilized to identify the elements present in each sample. A series of tests were completed in order to answer the question “can the Nuclear Barcode survive the explosion process and be adequately detected?” An identification taggant with this property is called a “survivable” taggant, this property is necessary for any identification taggant to be used as designed. Qualitatively, the results of the test series are successful, where taggant elements have been detected as much as 100% of tests performed. In tests where less than a 100% success rate occurred, it is theorized that it can be attributed to the delay between irradiating and counting being greater than the half-life of the element used. This method of tagging could prove useful for manufacturers of other products, since it has been proven to survive the high pressure and temperature detonation environment.