AN ANGLE-RESOLVING PHOTOELECTRON SPECTROMETER FOR THE SIMULTANEOUS MEASUREMENT OF CROSS-SECTIONS AND ASYMMETRY PARAMETERS USING SYNCHROTRON RADIATION

We describe an angle-resolving photoelectron spectrometer for atoms and molecules which uses the magic angle geometry in combination with multidetection such that cross sections and asymmetry parameters can be determined simultaneously. The instrument is based on the cylindrical mirror analyzer (CMA) design with the cylinder axis and the light beam collinear. Only the photoelectrons which are emitted in the "reverse" direction at the magic angle reach the ring-shaped position-sensitive detector. The complete system also incorporates a conical effusive gas source, in order to maintain cylindrical symmetry, and very efficient differential pumping between target and electron spectrometer. Results from the C 1s photoionization of CO2 demonstrate the kind of precision attainable.