Development of laser ionization mass nanoscope (LIMAS)

We have developed a new nano-beam time-of-flight secondary neutral mass spectrometry system: laser ionization mass nanoscope or LIMAS. The primary ion beam column was equipped with a Ga liquid metal ion source and aberration correction optics. The primary ion beam was down to 40 nm in diameter under a current of 100 pA with an energy of 20 keV. The sputtered particles were post-ionized under non-resonance mode by a femtosecond laser. The post-ionized ions were introduced into a multi-turn mass spectrometer. A mass resolution of up to 40 000 was achieved. The vacuum of the sample chamber was maintained under an ultrahigh vacuum of 2×10 ^-8 Pa. This instrument would be effective for ultrahigh sensitive analysis of nanosized particles such as return samples from asteroids, comets, and planets.