| Popis: |
An instrument for a sputtered neutral mass spectrometry with a quadrupole mass spectrometer (QMS) by resonance-enhanced multiphton ionization method is developed to study sputtered neutrals emission phenomena under ion irradiation in a low-energy region. We have prepared a pulsed primary ion beam and an ion counting system, and have optimized the operation parameter including a sample bias, energy analyzer voltages, pulsed timing of laser and ion beam, etc. A yield ratio of the lowest-lying excited state a5S2 to the ground state a7S3 for sputtered Cr atoms has been measured as a function of incident energy of Ar+ and O2+ down to 600 eV using a polycrystalline Cr sample. The yield ratio has become a constant value for the Ar+ incidence, while it has exponentially increased below 1 keV for the O2+ incidence. It is found that the internal energy distribution of sputtered Cr atoms has been significantly influenced by oxygen density at the surface. Copyright © 2011 John Wiley & Sons, Ltd. |
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