Scanning Microscopy


The results of measurements of cathodoluminescence efficiencies, decay characteristics and emission spectra of YAG:Ce, YAP:Ce, P47 (Y2SiO5:Ce) and CaF2:Eu single crystals at excitation by electrons with an energy of 10 keV and a current density of the order of 10-8 A cm-2 are presented. Advantages and disadvantages of the individual single crystals intended for application in electron microscopes are dealt with. Attention is paid to the photomultiplier tube (PMT) matching, degradation and afterglow of the mentioned single crystals. For YAG:Ce, the effect of the activator concentration of crystals and the effect of the cleaning and annealing of crystal plates are included. The proposal for the application of YAG:Ce as a scintillator and as an image screen in electron microscopy is given. Sizes of electron interaction areas and absorbed energy distributions are simulated by using Monte Carlo method based on the plural large angle elastic scattering. Cathodoluminescence widths of YAG:Ce single crystals for an impact electron in the energy range 10-100 keV are estimated.

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