Testing the AVNG

An attribute measurement system (AMS) measures a number of unclassified attributes of potentially classified material. By only displaying these unclassified results as red or green lights, the AMS protects potentially classified information while still generating confidence in the measurement result. The AVNG implementation that we describe is an AMS built by RFNC - VNIIEF in Sarov, Russia. The AVNG detects neutron and gamma radiation signatures and displays the three unclassified attributes of “plutonium presence,” “plutonium mass > 2 kg,” and “plutonium isotopic ratio (240Pu to 239Pu) < 0.1.” Prior to demonstration to a joint US/Russian audience, the overall operation and thresholds of the AVNG were tested using a number of multi-kg plutonium reference material (RM) sources manufactured for this purpose. As the AVNG was designed to incorporate an open mode (where all radiation data was displayed) as well as a secure mode (where only the red/green attribute lights were visible), the AVNG was tested in both modes. We will present data from these tests using unclassified plutonium RM sources as well as detector test results obtained using smaller calibration sources.