Improved performance of a Kratos SIMS instrument with a new energy filter.

We report on the improved performance of a hybrid Kratos/Atomika SIMS instrument (which comprises a part of a larger Kratos XSAM800/SIMS800 multi-technique instrument), which employs the Atomika A-DIDA microprobe ion gun. The improvement is made with the intention of improving the secondary ion collection efficiency by replacing the standard Kratos CMA-like narrow band-pass (1 eV) secondary ion energy filter in front of the quadrupole mass filter. The new energy filter consists of a lensing system, a field limiting aperture and a spherical sector energy analyzer. The new energy filter uses a high extracting field (100 V/cm) and optical gating via the lens and the field limiting aperture to permit increased angle of collection. The increased pass energy of the filter increases the band pass of the secondary ions which can be varied from 3 eV to 10 eV. In addition, the new filter has good imaging capabilities with variable magnification, of benefit in reducing background count rates.