A photoemission microscope with a hemispherical capacitor energy filter

A purely electrostatic photoemission electron microscope with a bandpass energy filter is described. The electron optics are of a hybrid design, incorporating a high-voltage and high-magnification objective and intermediate lens, coupled to a low-voltage hemispherical capacitor configured as an achromatic imaging bandpass filter. The electron optical system design is described, along with initial performance tests. The instrument is used for both imaging X-ray absorption spectroscopy and photoemission spectroscopy.