A new type of Secondary Ion Mass Spectrometer (SIMS) is under development at the NRL that will quantitatively measure elements and isotopes at unprecedented low abundance levels. The new instrument combines a dynamic SIMS with a Single Stage Accelerator Mass Spectrometer (SSAMS). SIMS is known for its high spatial resolution and high sample utilization. The addition of a SSAMS, accepting ions in place of the usual ion detector of the SIMS instrument, enables destruction of molecular ions that often interfere with SIMS measurements of trace species; typical for elements heavier than Zr (approximately 90 u), enabling purely atomic ion SIMS (ai-SIMS) analysis. The single stage nature of this AMS allows detection of positive ions, not normally available to AMS measurements. Trace level sensitivity for actinide, lanthanide, many transition metal, alkali, and alkali-earth elements will be greatly improved while retaining SIMS capabilities for spatial and depth distribution analysis, and allowing micrometer-scale features to be characterized. This world-unique capability will be applied to:
- Problems in nuclear safeguards and forensics
- Analysis of trace impurities in new engineered materials and structures being developed for high power electronics and sensors
- Measurement and location of contaminants in coatings and failed components
- Elemental and isotopic compositional analysis of high-value materials, such as those from NASA spacecraft sample-return missions.