Oregon Physics is now in the second phase of a research project funded by the Department of Energy, and in support of the National Nuclear Security Administration's (NNSA) mission to provide a national safeguard against the proliferation of weapons grade nuclear material.
During the production and handling of nuclear material, fine particulates are often released in trace amounts. The mobility of this fine material can cause it to distribute across a broad area, making it very difficult to clean up and remove evidence of illicit nuclear material processing. Hence particulate swabs from old nuclear operations can contain particles from the entire lifetime of the facility. The isotopic composition of the particulates are representative of the original material and can provide important information about the source, but high isotopic detection sensitivity and spatial imaging resolution are required.
Mass spectrometric techniques such as SIMS and RIMS have proven to be extremely valuable for the isotopic analysis of uranium and plutonium micro-particles derived from undeclared nuclear activities. In order for the international safeguard inspectors to be able to quickly and reliably analyze particulate debris from suspect sites, higher spatial resolution and higher throughput SIMS and RIMS instrumentation are required. While high spatial resolution is required to identify offending particles, high throughput is required in order to search through large quantities of particles to find those of interest. The expense of these high performance instruments ($3-$6M) limits the number that are available for this type of work, making enhanced throughput significant in efforts to ensure public safety against criminal activity involving radioactive material.
Until recently, the highest resolution oxygen focused ion beam has been provided by the Cameca NanoSIMS, operating with a duoplasmatron O- ion source. This system has provided 200nm SIMS imaging resolution (1pA/O-), with nominally 1 week of operation between ion source maintenance events. With the introduction of Hyperion II (replacing the duoplasmatron), imaging resolution has been increased to 50nm. The target resolution for this research project is 10nm, while also maintaining at least the 2000 hours lifetime of Hyperion II, and providing greater than a factor of 100 higher current density than the duoplasmatron at 200nm resolution.