抄録
A sputtering mass spectrometer with a cesium primary ion source was constructed. Two types of the surface ionization ion source for producing the cesium ion beam were made and their characteristics were studied. The second type of the source, which had two filaments in the ionization chamber, proved to have the superior performances. The beam current of 0.5-2.0×10-7 A was obtained for more than 50 hours. The diameter of the beam on the surface of the target was about 0.45mm.By using cesium ions as the primaries, the charge up effect due to the ion bombardment of insulating materials was much reduced, and the stability of the secondary ion current was enough for accurate analysis. Results of the preliminary measurements for the isotopic abundance ratio of lithium in the potassium alum crystal were described. The possibility of the high sensitive analysis of negative secondary ions was pointed out.
