title: Automatic control of the ion-illumination angle in a spark-source mass spectrometer.
abstract: Automatic adjustment of only the spark-gap width in a spark-source mass spectrometer does not ensure that optimum conditions of electrode geometry are maintained with respect to the ion-optics system. A device has been developed which simultaneously maintains a constant gap width and also a more constant z-axis ion-illumination angle. This is the first development to utilize ion-optics parameters to adjust the sparking electrodes automatically. The system maintains the electrodes in an optimum configuration such that higher and more constant instrument sensitivity is maintained automatically. In addition, a significant improvement in the precision of instrumental response is demonstrated. It appears that relative isotopic abundances can be determined directly by the spark-source method which are comparable to those obtained in some cases by surface ionization or by electron bombardment. Results are given that support this contention.
authors.affiliation: Ames Laboratory, USAEC and Department of Chemistry Iowa State University, Ames, Iowa 50010, U.S.A.
authors.forename: R J
authors.initials: RJ
authors.lastname: Conzemius
authors.forename: H J
authors.initials: HJ
authors.lastname: Svec