UV-light microscope: improvements in optical imaging for a secondary ion mass spectrometer

Abstract

A large radius secondary ion mass spectrometer (SIMS) has been used for in situ stable isotope analyses of geological samples at the scale of 1–10 μm. However, the original reflected light microscope of the CAMECA IMS 1280 SIMS had an optical resolution of ∼3.5 μm, which made it difficult to accurately position the analytical beam on the sample at the μm scale. We modified the optical microscope to use ultraviolet (UV) light illumination and UV compatible optical components, keeping the same mechanical design inside the vacuum chamber. The optical resolution was improved to 1.3 μm with the UV-light microscope system. In addition, we wrote Badgerscope©, a LabVIEW based software for sample imaging, which greatly enhanced the accuracy of positioning and efficiency of instrument operation. These improvements can be adapted to other micro-beam instruments where complex optical paths may be imposed by instrument design.