A WAVELENGTH DISPERSIVE SPECTROMETER FOR ANALYTICAL ELECTRON MICROSCOPY

THE DEVELOPMENT OF A NOVEL NON-SCANNING WAVELENGTH DISPERSIVE SPECROMETER (WDS) FOR ANALYTICAL ELECTRON MICROSCOPY (AEM) IS THE OBJECTIVE OF THIS PROJECT. THIS SPECTROMETER IS DESIGNED TO PROVIDE SUFFICIENT ENERGY RESOLUTION OVER BROAD REGIONS OF THE SOFT X-RAY SPECTRAL REGION (FROM 100 TO 2000 EV) TO ALLOW THE OBSERVATION OF THE K-EMISSIONS OF THE LIGHT ELEMENTS (THOSSE WITH ATOMIC NUMBERS LESS THAN 10) AS WELL AS L, M, AND N EMISSIONS OF THE HEAVY ELEMENTS. THE LARGE SOLID ANGLE OF THIS SPECROMETER AND ITS NON-SCANNING GEOMETRY DECREASE THE ANALYSIS TIME COMPARED TO CONVENTIONAL WDS INSTRUMENTS WHILE OFFERING AT LEAST A FOURFOLD INCREASE IN SPECTRAL RESOLVING POWER COMPARED TO ENERGY DISPERSIVE DETECTORS CURRENTLY OFFERED IN THE AEM MARKETPLACE. THE PHASE I OBJECTIVE IS TO EXPERIMENTALLY EVALUATE THE PERFORMANCE OF A PROTOTYPE SPECTROMETER IN TERMS OF LOWER LIMITS OF DECTECTION IN THE ENERGY RANGE FROM 150 TO 300 EV IN A RE-ENTRANT AEM ENVIRONMENT. THIS OBJECTIVE WILL BE ACCOMPLISHED BY THE FABRICATION OF A SINGLE CHANNEL PROTOTYPE OF THE SPECTROMETER AND THE MEASUREMENT OF THE SIGNAL AND BACKGROUND LEVELS IN A MODERN AEM.