Ultra High Brightness Plasma Ion Source for SIMS Imaging of Actinides at the Theoretical Resolution Limit.

This proposal outlines a project aimed at providing a radical improvement in ion source technology that can be applied to the mass spectrometric analysis of actinides. The state-of-the-art secondary ion mass spectrometers (SIMS) employ the duoplasmatron ion source to create the primary ion beam for actinide analysis. The duoplasmatron only has sufficient brightness and a small enough energy spread to create focused oxygen ion beams as small as 200nm in diameter, with a very low ion beam current of & lt;1pA. In order to analyze sub-micron actinide particles with sufficient speed, the current density needs to be increased by approximately two orders of magnitude (100x). Focused oxygen beam diameters as small as 10nm are required to provide the highest possible imaging resolution using the SIMS technique, but today this is far from possible. Furthermore, the lifetime and reliability of the duoplasmatron can be very problematic, causing a significant amount of downtime for these very expensive instruments. Oregon Physics developed its first high density plasma source prior to this project, for pilot studies and as a stepping stone to the work being carried out here. Hyperion has realized a factor of 10 increase in current density over the duoplasmatron and extended source life significantly. This work has been leveraged in the 1st phase of this project. Phase I incorporated a series of detailed analytic and numeric simulations of heat transfer, electromagnetic field calculations and ion extraction optics employed with the new ion source. A proof- of-concept (PoC) source has been engineered, built and is now undergoing detailed experimental studies. Early data shows a significant gain in RF power efficiency and a level of thermal management that will allow for a factor of 40 increase in power density, over and above that demonstrated with Hyperion. In Phase II, we will fully characterize this PoC source, refine the design and integrate onto our 30kV source isolator. An ion optical column will be built that is suitable for ultra-high resolution SIMS imaging, and capable of providing an oxygen beam diameter of 10nm and xenon beam diameters of 7nm. Commercial Applications and Other Benefits: Applications include rapid, high resolution SIMS and RIMS (resonant ion mass spectrometry) analysis of actinides. The primary objective here is to enhance the analysis equipment used by our nations nuclear forensic scientists in their efforts to prevent nuclear proliferation amongst rogue nations and terrorist organizations. If successful, this project will reduce SIMS analysis times from hours to seconds and improve the imaging resolution by over an order of magnitude. In addition to actinide analysis with SIMS, the ion optical column can also be used for high resolution and throughput focused ion beam machining, with a range of ion species. Applications here span the semiconductor, biomedical, energy research industries, as well as national security.