FAST ATOM BOMBARDMENT SECONDARY NEUTRAL MASS SPECTROMETRY.

Secondary neutral mass spectrometry has been studied under sample bombardment using a fast atom beam as the primary beam. Sputtered atoms from a sample bombarded by fast Ar atoms of 3keV, 10 mu A (converted values to an ion current) are ionized through thermo-electron bombardment or photoionization using a mercury lamp. The ionization coefficiency achieved during thermoelectron bombardment is found to be superior to that achieved by photoionization. The spectrum intensity of the sputtered atoms ionized by electron bombardment is confirmed to be higher than that of secondary ions, corresponding to the content ratio of sputtered atoms and secondary ions in sputtered particles from the sample. In this type of equipment, insulator analysis is easily accomplished without disturbance by sample charging since the primary beam has no charge.