A NEW MULTIDETECTION SPECTROMETER FOR STUDIES OF ANGLE-RESOLVED ELECTRON DISTRIBUTIONS

A novel multidetection electron spectrometer is presented, designed for the parallel measurements of angular distribution in gas-phase electron scattering experiments. It is called MAPDESS. The same design is suitable for angle-resolved photoelectron spectroscopy. The main feature is its geometry given by the analyzer: a truncated spherical mirror symmetric about the scattering center and whose ring-shaped exit is coupled to 19 channel electron multipliers, thereby allowing parallel multi-angle detection. The angular resolution is ± 3°, with an overall energy resolution of about 25 meV in some measurements. As examples, various angle dependence measurements are presented, such as electron energy loss spectra for the low-lying states of helium, Feshbach resonances in the differential elastic and inelastic cross sections of rares gases, resonant vibrational excitation in nitrogen, along with spectra of ejected electrons following the autoionization in argon. © 1990.