First Results of a Monochromized 200KV TEM

Abstract FEI is currently finishing the construction of a monochromized 200kV (S)TEM which aims at 0.1 eV resolution in Electron Energy Loss Spectroscopy (EELS). This requires improvement of the 200kV supply, improvement of the EELS spectrometer, and the incorporation of an electron beam monochromator. This microscope will be delivered to the National Centre for High Resolution Electron Microscope at the University of Delft. The present 200kV supply contributes 0.2 eV to the energy resolution because of its instabilities, drift and high frequency ripple. in order to reduce this, mechanical as well as electrical damping elements are being added, and sources of cross-talk between the high frequency generator and the high tension are eliminated. in this paper, we present preliminary results obtained with a standard 200kV supply; we expect to present results of the improved 200kV supply at the conference. The resolution of a present-day standard 200kV spectrometer is now typically 0.4 eV. in order to improve on this, GATAN has developed a HR-EELS spectrometer for the monochromized TEM.