Journal of Electron Spectroscopy and Related Phenomena, 28 zyxwvutsrqponmlkjihgfedcbaZ (1982) 123-128 Elsevier Scientific Publishing Company, Amsterdam - Printed in The Netherlands zyxwvutsrqponmlk A UV PHOTOELECTRON SPECTROMETER FEATURING RAPID ANALYSIS J. DELWICHE*, M.-J. HUBIN-FRANSKIN*, M. FURLAN** and J. E. COLLIN Uniuersiti de L&e, Labomtoire de Spectroscopic d *Electrons, Sart-Tilman, B-4000 Liige 1 (Belgium) D. ROY, B. LECLERC, P. ROY, A. POULTN and J.-D. CARETTE Dipartement de Physique et C.R.A.M., Uniuersitk Laual, Quebec, P.Q. GlK 7P4 (Canada) (Received 21 June 1982) ABSTRACT An improved sensitivity electron spectrometer for use in UV photoelectron spectro- metry has been developed for rapid analysis. High sensitivity is achieved by the use of a focal-plane position-sensitive multidetector consisting of a linear array of photosensitive diodes (a CCD imaging device) allowing parallel detection and rapid data-acquisition. In the measurement of the He (I) 58.4 nm photoelectron spectrum of Ar, the gain in acqui- sition time is estimated to be by a factor of “12. INTRODUCTION UV photoelectron spectrometry (PES) is recognised as a powerful tool for the investigation of ionic molecular states. In addition to the purely spectro- scopic aspects of this technique, it has been shown recently by Lorquet et al. [ 1] that kinetic information concerning the evolution of the wave packet of an electronic state on its potential-energy curve can be obtained from the Fourier transform of a photoelectron spectrum. During preliminary investi- gations for the set-up of this new mathematical treatment of the spectra, several instrumental difficulties were encountered, the most difficult to over- come being slight shifts of potential during the accumulation time. The necessity to shorten this time led us to search for a new type of electron spectrometer with increased sensitivity. As a result, we have developed a 127” cylindrical electrostatic analyser fitted with a position- sensitive multidetector allowing parallel data-acquisition. Electronic position-sensitive multidetectors presently available can be sub- * Chercheur qualifii of the Fonds National de la Recherche Scientifique, Belgium. ** Chercheur of the Action de Recherche Concert&e of Belgium. 0368-2048/82/0000-0000/$02.75 01982 Elsevier Scientific Publishing Company