Improvement of ionization yield in sputtered neutral mass spectrometry using pulsed infrared and ultraviolet lasers

Abstract

A new laser ionization method for sputtered neutral mass spectrometry (SNMS), which the authors call “dual-laser SNMS,” was developed to increase the ionization probability and improve sensitivity. In this technique, pulsed IR and UV lasers irradiated sputtered atoms simultaneously, while the additional UV laser pulse enhanced the ionization process. The useful yields of the target elements increased by 10%–20% compared to using the IR irradiation alone, and the yield increased with increasing UV power. In addition, there was little correlation between the ionization potential and the ratio of the ionization enhancement. Therefore, dual-laser SNMS was effective for the analysis of elements with higher ionization potential.