Resolution in the photoemission energy analyzer is investigated theoretically for the case of a finite emitter in a spherically symmetric retarding field with a magnetic field present. Resolution errors shift and broaden structure in measured energy distribution curves by an amount which is energy dependent. The analysis is applicable to the spherical capacitor analyzer, the screened emitted geometry, the multiscreened LEED system, and others. Electrolytic tank measurements show field distortions caused by a flat emitter, the emitter support, and the window aperture. Spherical symmetry is restored to a configuration with a large emitter or support structure by surrounding the emitter with a screened, fieldhyphen;free region. An explanation is given for the reasonable resolution obtained for any small emitter completely enclosed by a collector. Distortion of measured electron energy distributions caused by reverse photoemission, reflected electrons, and fringing fields at the emitter is also discussed.
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