TREATY VERIFICATION WITH PASSIVE NEUTRON SIGNATURES

Cosmic ray interactions with materials result in secondary neutrons wh ich are easily measurable. The magnitude of this neutron flux depends on geomagnetic latitude, altitude, and on the materials that constitut e the local environment. In general the neutrons produced by cosmic ra ys in a given object depend on the atomic number, density, and total m ass of the elements which constitute that object. Any massive object w ill have a unique ''neutron signature'' depending on its materials and structure. To test if this phenonemenon might be used to determine if a closed canister contains a specific object, such as a missile, we c onducted a proof of concept study. The study had two parts, experiment al and Monte Carlo simulations. The object was to perform measurements and simulations of a ''block missile mockup''. We constructed the moc kup at approximately one-sixth the mass of a real missile. A clear neu tron signature was observed from this mockup experimentally, and model ing predictions agreed well with the data. Predictions from our result s indicate that a full sized missile should produce a very distinct si gnature.