The miniature cylindrical mirror analyzer: A new tool for surface analysis

Abstract

The design and performance of a new miniature cylindrical mirror analyzer (CMA) are presented. The CMA comprises outer and inner cylinders, an integral on-axis electron gun, and a detector system consisting of ring aperture and channeltron, all mounted on a single 2.75 in. (70 mm o.d.) Conflat flange. Entrance angle, sample-to-detector distance, and polar cone angle were chosen, in consideration of second order focusing effects, which optimized analyzer transparency and resolution. Fringe field correction at the ends of the CMA is made by means of six rings precisely separated by sapphire insulators. The electron gun is a one-lens electrostatic system equipped with an x-y deflector for beam adjustment and scanning. A CeB6 low temperature cathode operating at up to −3.0 keV delivers emission current up to 100 μA. The energy range of analyzed electrons can be varied between 0 eV and 3.0 keV. The flange mounting also incorporates a high precision z-motion drive for optimization of the working distance. The control electronics and software permit operation of the instrument in pulse and analog phase sensitive detection modes. Results obtained with this new mini CMA for a W(100) surface demonstrate an energy resolution (ΔE/E) of 0.9%, which is comparable to larger 6 in. (152 mm) flange-mounted instruments. The very small size of the mini CMA permits its use in small or crowded ultrahigh vacuum chambers or where only 2.75 in. ports are available, thereby increasing flexibility in surface analysis.