Photoelectron branching ratios with a cylindrical mirror energy analyzer

A cylindrical mirror photoelectron energy analyzer suitable for measuring photoelectron branching ratios is described. The analyzer incorporates a pre-retarding/ accelerating system. This configuration is shown to have advantages over a conventional mirror analyzer in reduced pressure-sensitive scattering effects which can effect the accuracy of the branching ratios, and in increased sensitivity to low energy electrons. The electron collecting efficiency of the analyzer for a number of operating modes is given.