ESCASCOPE - A NEW IMAGING PHOTOELECTRON SPECTROMETER

This communication describes the development, operation and some applications of a new imaging photoelectron spectrometer developed at VG Scientific. The instrument uses a hemispherical electrostatic sector analyser to take advantage of the high sensitivity and high energy resolution of these devices for photoelectron spectroscopy. As such the performance is comparable with other more conventional XPS instruments using hemispherical analysers. However, use is also made of the focusing properties of this device to generate photoelectron images. The latent problem of the convolution of energy with space in the output plane of the analyser has been avoided by using a novel arrangement of input and output optics. This enables the instrument to also function as a photoelectron microscope producing high resolution (< 10-mu-m), energy filtered photoelectron images in real time using a standard MgK-alpha X-ray source. Imaging XPS is an ideal technique for obtaining spatially resolved, quantitative, chemical information for insulating and in particular organic surfaces. Some examples of such k analyses are given.