RAPID LIGHT ELEMENT ANALYSIS WITH TRANSMISSION ELECTRON MICROSCOPY

THIS PROJECT ATTEMPTS TO EXPERIMENTALLY DEMONSTRATE A RE-ENTRANT LIGHT ELEMENT X-RAY FLUORESCENCE ANALYZER FOR ANALYTICAL TRANSMISSION ELECTRON MICROSCOPY (TEM). THE ANALYZER RELIES ON ADVANCED X-RAY OPTICAL COMPONENTS TO COLLECT AND TRANSPORT CHARACTERISTIC RADIATION EMITTED FROM LIGHT ELEMENTS (WITH ATOMIC NUMBERS BELOW 10) DURING ELECTRON MICROSCOPY. CALCULATIONS SHOW THAT THIS X-RAY OPTICAL SYSTEM IS 50 TIMES MORE EFFICIENT THAN THE MOST ADVANCED WAVELENGTH DISPERSIVE SPECTROMETERS COMMERCIALLY AVAILABLE OR UNDER DEVELOPMENT. THE INCREASE IN EFFICIENCY IS MADE POSSIBLE BY THE RECENT DEVELOPMENT OF LARGE SOLID-ANGLE OPTICAL COMPONENTS THAT RELY ON X-RAY MULTILAYERCOATINGS TO TRANSPORT CHARACTERISTIC RADIATION AND REJECT UNWANTED BACKGROUND RADIATION. IN PHASE I OF THIS PROJECT, AN ANALYZER DEMONSTRATOR UNIT IS BEING CONSTRUCTED TO DETECTCHARACTERISTIC BORON RADIATION EMITTED DURING TEM EXAMINATION OF BORON-CONTAINING SAMPLES. AMONG THE LIGHT ELEMENTS, BORON PRESENTS THE GREATEST QUANTITATIVE ANALYSIS CHALLENGE BECAUSE OF ITS LOW FLUORESCENCE YIELD AND THE PRESENCE OF INTERFERING RADIATION. THE PHASE I EFFORT WILL INTEGRATE A TEM SAMPLE STAGE, A BORON COLLECTION OPTIC, AND A DETECTOR TO FORM A RE-ENTRANT ANALYZER. THIS UNIT WILL BEDEPLOYED IN A TEM TO EXPERIMENTALLY DEMONSTRATE THE ANTICIPATED EFFICIENCY IMPROVEMENTS AND CONSEQUENT REDUCTIONIN BORON ASSAY TIME. FOLLOWING A SUCCESSFUL PHASE I DEMONSTRATION, PHASE II AIMS TO DESIGN, FABRICATE, AND DEMONSTRATE A RE-ENTRANT FOUR "COLOR" ANALYZER PROTOTYPE THAT CAN SIMULTANEOUSLY ASSAY BORON, CARBON, NITROGEN, AND OXYGEN.