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Abstract
The partial photoionization cross sections of H$\sb2$, SO$\sb2$, and H$\sb2$O were calculated from the measured photoionization branching ratios and the known total photoionization cross sections. The branching ratios were measured with a time-of-flight mass spectrometer and synchrotron radiation. The branching ratios of H$\sb2$, SO$\sb2$, and H$\sb2$O were measured for 100 $\sim$ 410, 150 $\sim$ 380 and 120 $\sim$ 720 A. We also measured the photoionization yield of SO$\sb2$ from 520 to 665 A using a double ion chamber and a glow discharge light source.
The principle of a time-of-flight mass spectrometer is explained. New calculations were made to see how the design of the mass spectrometer, applied voltage, and kinetic energy of the ions affect the overall performance of the mass spectrometer. Several useful techniques that we used at the synchrotron for wavelength calibration and higher order suppression are also discussed.
