Year
1998
Abstract
Three complementary measurement technologies have been identified as candidates to verify excess plutonium of weapons origin. These technologies: high-resolution gammaray spectroscopy, neutron multiplicity counting, and low-resolution gamma-ray spectroscopy are mature, robust technologies. The high-resolution gamma-ray system called Pu-600 uses the 630- to 670-keV region of the emitted gamma-ray spectrum to determine the ratio of 240Pu-to-239Pu. This ratio can identify the presence of weaponsgrade plutonium as well as the presence of plutonium. Neutron multiplicity counting is well suited for verifying a threshold quantity of and for assuring that the plutonium is consistent with weapons-quality material (e.g., not residue or waste). In addition, multiplicity counting can independently verify the presence of plutonium by virtue of a measured neutron self-multiplication and can detect the presence of non-plutonium neutron sources. The low-resolution gamma-ray spectroscopy technique is conceived of as a template method that can provide, in principle, continuity-of-knowledge for an item that enters a verification regime and remains under the regime. In the initial verification of an item, multiple regions of the measured low-resolution spectrum form a gammaradiation- based template for the item that can be used for comparison in subsequent verifications. In this paper, we will discuss these technologies as they relate to the different attributes that could be used in a verification regime.