Standoff Detection of Radiological Materials using Light Filaments

The ability to detect radiological materials at standoff distances of a kilometer or more would be invaluable to national security and nonproliferation efforts. In particular, it is important to be able to distinguish isotopes of uranium and other elements associated with nuclear weapons development and use. Current methods for identifying radiological isotopes require direct sampling. Laser based methods such as plasma emission spectroscopy and laser induced breakdown spectroscopy have shown promise in the laboratory for detection of some radionucleotides, however, these methods cannot be performed at distances of more than about 10 meters. Southwest Sciences and the University of New Mexico propose to investigate the use of light filaments for spectroscopic detection of radionucleotides over large distances of a kilometer or more. Narrow diameter laser beams have been propagated over large distances and can potentially be used to create a plasma at a distant target for emission spectroscopy. This phenomenon is known as light filamentation and its use for standoff atomic emission spectroscopy is promising. The opportunity is that a self-trapped lament would have enough intensity to vaporize and excite a material remotely, and enough energy to make the glow of that excitation visible through a telescope collection system and spectrometer at long distances. The ultimate objective is the development of this technology into a mobile field instrument. Commercial Applications and Other Benefits: The development of a method for remote sensing of radiological materials, particularly uranium isotopes and nuclear decay products related to weapons development is of high importance to the security of the United States and its allies. This technology would aid nuclear non-proliferation and nuclear forensics efforts. Light filament technology developed for plasma emission spectroscopy of remote targets may also have other important uses such as detection of trace explosives and of soil contaminants in inaccessible or dangerous places such as abandoned mining and industrial operations.