X-ray Intensity Measurements from Ores Using Semiconductor Detectors and Radioisotopic Excitation.
Ch Applic of Low Energy X- & Gamma-rays Symp Gordon & Breach NY 1971 Dec; 3:17 pages
Recent experimental work at the Bureau of Mines has involved use of radioisotopic excitation combined with semiconductor detectors to determine the sensitivity for single-element x-ray analysis. Peak- to-background ratios have been measured for gold and silver and for other high-z elements in ores. The ease of exciting the energetic k x-rays from high-z elements with radioisotopes offer unique advantages for ore analysis. Sensitivities below 100 ppm for high-z elements in ores are possible because of the good stability of radioisotopic excitation and detecting x-rays with semiconductor detectors. During the course of this experimentation, monoenergetic excitation with gamma-emitting or electron-capture radionuclides was found excellent for both single and multielement x-ray excitation in ores. Higher peak-to-background ratios were obtained compared with broad-energy excitation using bremsstrahlung sources. Equally important for analysis are the discrete scatter peaks obtained with monoenergetic excitation. The fluorescent x-ray intensity-to- compton scatter ratio has been used to overcome changes in x-ray intensities because of absorption coefficient variations in the ore matrix. More recent work has shown the importance of separating the compton and coherent scatter events to achieve compensation over wider matrix variations.
Ch Applic of Low Energy X- & Gamma-rays Symp...; Gordon & Breach, New York, V.3, Dec.1971, PP.147-163