Dynamic IR Imaging of Nuclear Weapon Platforms for Treaty Verification

The Defense Threat Reduction Agency’s (DTRA) Arms Control Technology Division sponsored research at the Oak Ridge National Laboratory (ORNL) into the efficacy of infrared (IR) classification of full-up nuclear weapons as an alternative technology for treaty verification. In our effort, dynamic IR measurements were made on a BG61-11 weapon casing. These measurements differ from normal (static) IR measurements in that changes in surface temperature profiles are monitored as an object is actively heated or cooled. We demonstrated the capability of performing these types of measurements using limited cooling in the form of vortex coolers. These coolers have no electrical requirements and use only instrument air to provide -20°C air at their exhaust port. The tests showed the ability of dynamic IR imaging to reveal information about structures inside the casing not accessible with more conventional techniques like X-rays or static IR imaging. This information includes the general structure of underlying components in thermal contact with the shell of the casing as well as the radiative power of embedded thermal sources. The technique thus has the potential for providing two independent parameters, internal structure and source power, that could compliment information from other existing technologies for weapons categorization.