SUMMARY
ADDITIONAL COMMITTEE MEMBER: DR. TANYA OXENBURG (US ARMY TEST AND EVALUATION COMMAND) The characterization and measurement of the spatial, temporal and energy emission of air-scattered photons and neutrons generated near accelerator-based bremsstrahlung photon sources is becoming important in many modern applications. The national and homeland security research community is interested in developing technologies which can detect illicit materials at greater standoff distances in outdoor environments. These systems are referred to as “active” interrogation systems and are defined as inspection systems that take advantage of an externally applied “source” to perform traditional imaging of, or to stimulate characteristic emissions from, an inspected object. A key concern in the development of these systems is the ability to effectively predict the photon and neutron doses at long standoff distances from these sources in order to ascertain the operational safety of said systems. Current computational simulation tools have the ability to effectively model these systems, however, a paucity of experimental data exists in benchmarking the results of these simulations. The objective of this work is to perform an integral benchmark air scatter experiment for accelerator-generated primary and secondary radiations (photon and neutron). The Los Alamos National Laboratory Monte Carlo N-Particle transport code (MCNP5) and the eXtended version (MCNPX) will be utilized to model the radiation transport. Several integral measurements will be conducted to determine the photon and neutron dose both in the beam (on-axis) and outside of the beam (off-axis).