RESUMEN
Low enriched uranium samples of unknown origin were analyzed by 16 laboratories in the context of a Collaborative Materials Exercise (CMX), organized by the Nuclear Forensics International Technical Working Group (ITWG). The purpose was to compare and prioritize nuclear forensic methods and techniques, and to evaluate attribution capabilities among participants. This paper gives a snapshot of the gamma spectrometric capabilities of the participating laboratories and summarizes the results achieved by gamma spectrometry.
RESUMEN
Targets are essential in experimental nuclear sciences as a source of stationary nuclei for nuclear reactions with ion beams. Typically, targets should be chemically pure, uniform, homogeneous and crack-free over the irradiation area, while also being structurally rigid. The polymer-assisted deposition (PAD) method uses a water-soluble multidentate polymer that chelates metal precursors in solution. This polymer-metal solution is then spin coated and annealed to yield a crack-free, homogeneous metal oxide film. In this protocol, nuclear targets are created using PAD on silicon nitride (Si(3)N(4)) windows with silicon frames. Silicon wafers ([100], single-side polished) coated with 1 microm of silicon nitride on both sides are patterned and etched to create 1-microm silicon nitride windows. The PAD solution is then spun onto the silicon nitride window and annealed to create a thin, uniform metal oxide film of variable thickness on top of the silicon nitride backing. The production of a target window and the deposition of a thin film ranging from 50 to 150 nm takes approximately 13.5 h. Subsequent reapplications to grow thicker films require an additional 5 h per application.