LBNL: Assessing Impact of Monoenergetic Photon Sources on Nonproliferation Applications

LBNL PI: Cameron Geddes

Near-monoenergetic photon sources (MPSs) promise improved sensitivity at greatly reduced dose in existing applications and new capabilities in other applications, including material screening, treaty verification, non-destructive analysis of spent nuclear fuel, and emergency response. The advantage lies in the ability to select energy, energy spread, flux, and pulse structures to deliver only the photons needed for the application, while suppressing extraneous dose and background. Current broad-band photon sources deliver unnecessary dose that in some cases also interferes with the signature to be detected and/or restricts operations. While MPSs can in principle resolve these issues, source parameters trade off against one another (for example, tight constraints on photon bandwidth will reduce available photon flux). In many cases, the size and operability of an MPS and its support systems are also key restrictions. These tradeoffs, together with differences in detectors and backgrounds represent a large operation space which must be characterized in order to understand and define needs for each application, and hence to deliver a system with improved performance. MPS improvement of capabilities in applications where nuclear resonance fluorescence (NRF) or photofission signatures are leveraged, as well as in radiography applications, have been demonstrated in lab experiments using fixed facility MPSs such as the High-Intensity Gamma Source (HIGS). Transportable MPSs are required for some nonproliferation missions, and are being developed.  There is need for a cohesive body of work to define the scenarios under which quasi-monoenergetic sources can deliver important advantages. The project team will evaluate nonproliferation applications where MPSs provide advantages over current capabilities by conducting a two-year study with the following goals: 1) Identify a broad range of applications where monoenergetic photon sources may have a high-impact; 2) Determine application requirements, current capabilities, and gaps for these applications; 3) Flow-down the application requirements to determine photon source requirements; 4) Assess the performance of monoenergetic photon sources in these applications, including source tradeoffs and constraints (e.g. bandwidth, intensity, divergence, portability…); and 5) Identify applications where MPSs could have a strong impact.  It will identify a sequence of applications from early opportunities at moderate performance that can be deployed soonest, to those that will require the highest source performance and hence further development. It will further identify which source parameters are most important, to allow optimization of tradeoffs between parameters in source design (e.g. bandwidth, yield, repetition rate, radiation dose to target and bystanders, size and operational complexity). This will enable a coordinated program to deliver high-impact, next-generation systems with greatly reduced dose and increased detection and measurement capabilities.