Abstract
By the adoption of an ion current stabilizer which keeps the ion current constant during measurement, we constructed a mass spectrometer which directly indicates the value of the isotopic abundance ratio without any calculations. Although this method included two kinds of technical difficulties, these difficulties were overcome and our aim has been attained. The ion current stabilizer keeps the ion current of the larger peak constant by controlling the emission current of electrons. In the measurement of samples which containing0. 2-0. 5atomic percent of36Ar, the precision is maintained at three figures, though this method includes the error consisting of the theoretical error, the overlapping of its background and the error from the mass discrimination effect. A great many samples could be measured conveniently, precisely and continuously. We could widely lessen the labor of the measurement by use of an automatic sample introduction equipment with this apparatus.
