Measuring device for the investigation of photoionization processes by means of the coincidence of photoions and photoelectrons

A device for studying photoionization is described which consists of a mass spectrometer for analyzing ions and a photoelectric spectrometer for analyzing electrons. A monopole mass spectrometer with photoionization is used and the source of ionizing radiation is the glow discharge of a quartz lamp at inert gas pressures of 0.5-3.0 torr. Positive ions formed by photoionization are focused by means of an ion-optic lens on the aperture of the monopole analyzer. The photoelectric spectrometer uses a grid analyzer to which a cut-off voltage is applied. Electrons with kinetic energies exceeding this potential traverse the grid and are voltage-focused on the electrodes at the input of a photomultiplier.