A Spherical Plate Electrostatic Energy Analyzer.

摘要

A kinetic energy analyzer, to be used in proposed experimental studies of ion-atom and ion-molecule collision phenomena, has been designed and constructed. This instrument is of the electrostatic, 180 degree deflection type, and has hemispherical electrodes with radii of curvature of 1.400 and 1.600 inches respectively. The entrace and exit defining slits are identical circular apertures, 0.020 inches in diameter, spaced 3.000 inches apart. This configuration gives a nominal kinetic resolution of + or - 0.01E sub o, where E sub o is the mean kinetic energy of ions entering the analyzer. The device is designed to operate with E sub o greater than or equal to 5 e.V, thus giving an optimum K.E. bandwidth for transmitted ions of Delta E sub o = + or - 0.05 e.V. First-order aberrations, and the effects of fringing E fields in the vicinity of the defining apertures, have been taken into account quantitatively in the analyzer design. One of the most important applications of the analyzer will be the measurements of K.E. spectra of energetic ions produced in 25-5000 e.V. collisions. For high resolution measurements (at E sub o approx 5 e.V., giving Delta E sub o approx 0.05 e.V.), it is thus necessary to retard the fast ions leaving the collision region by a factor varying from about 5:1 to 1000:1. A relatively simple cylindrically-symmetric electrostatic lens system has been designed for this purpose. The rather extensive calculations necessary for this design were carried out by means of a computer program, based on paraxial ray electron-ion optics. (Author)