New instrument for microbeam analysis incorporating submicron imaging and resonance ionization mass spectrometry

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Abstract
A new reflectron time‐of‐flight mass spectrometer for surface analysis has been developed that incorporates a Schwarzschild all‐reflecting microscope. The instrument is configured for secondary ion mass spectrometry and secondary neutral mass spectrometry using either ion beam bombardment or laser ablation for sample atomization. The sample viewing and imaging system of this instrument enables in situ laser microanalysis with a lateral resolution below 1 μm. The major advantages of using a Schwarzschild objective include good lateral resolution, easy design, low cost, complete achromatism, and both viewing the sample and extracting secondary or photoions normal to its surface. The instrument has a mass resolution of m/Δm≥2000 and is capable of measuring elemental and isotopic compositions at trace levels using resonance ionization. The isotopic ratios of trace concentrations of Ti in μm size SiC grains separated from meteorites were measured. The extremely low ablation laser power used in the above experiment points to the possibility of using low‐cost laser systems for laser microprobe applications.