mass spectrometer for neutral atoms with laser ionized gesputterte, are

摘要

An ion beam (22) is impinged against a solid sample (25) to sputter neutrals (26). The neutrals thus sputtered are ionized by a UV laser beam (28) to obtain photoions (29). The photoions are guided to a quadrupole mass analyzer (31) through an ion extraction electrode (30) to extract ions having a desired mass. The extracted ions are made incident upon an ion detector (32) to derive ion pulses. The number of ion pulses is counted by a counter (33) through a signal gate (38) which is opened only during a time period that the photoions reaches the ion detector. A mass of the neutrals having a desired mass is analyzed from the counted value in the digital manner. A time period required for extracting the photoions is extended to perform the pulse counting without being influenced by the secondary ions which causes noises, so that the mass analysis can be performed with a high sensitivity. IMAGE