X-ray excited optical fluorescence of trace rare earths in yttrium phosphate and yttrium vanadate hosts. Part per giga level determination of rare earth impurities in yttrium oxide

Abstract

Y203 is a common starting material for the preparation of various solid-state luminescent materials. Since the luminescent efficiency of these materials may be adversely affected by the presence of ultratrace rareearth impurities, there has existed a pressing need for an analytical technique capable of assessing the purity of Y203. A comparative evaluation of the X-ray excited optical fluorescence spectra of various yttrium-containing compounds has revealed that YP04 and isostructural YV04 are superior hosts for the ultratrace determination of the Ce to Yb series of impurities occurring at the part per giga (1 in 101 23456789) level in highly purified YA.The unique optical fluorescent spectra of rare-earth activated materials has found widespread application in diverse industrial products such as solid state lasers (YAGNd), color television tubes (Y202S-Eu), and image conversion devices (Yi_zYbz02S • Er) (7). The efficiency of these materials, which are often compounds of yttrium, may be dependent on the presence of rare-earth impurities at the part per million levels because they may contribute to energy transfer processes (2-4). As a consequence, there is a pressing need for the preparation of ultra high purity Y2Os specially free from rare-earth impurities and for the development of sensitive analytical techniques to match these developments. The latter requirement has only recently been met by two simple but sensitive analytical techniques that take advantage of spectrometric methods of detection of the optical line fluorescence of rare-earth impurities excited by electrons, i.e., cathodoluminescence (5-7) or by X-rays (8-11), hereafter referred to as X-ray excited optical fluorescence (XEOF).Our own investigations with the XEOF technique have shown that quantitative results at the fractional ppm level or

On experimental attenuation factors of the amplitude of the EXAFS oscillations in absorption, reflectivity and luminescence measurements

“…-It has been recognized for a long time that a number of elements [21,22] (e.g. rare-earth cations), if placed in appropriate environments, had a strong emission of UV-visible radiations when excited by X-ray photons.…”

Emission spectra of LnPO4:RE3+ (Ln=La, Gd; RE=Eu, Tb and Ce) powder phosphors

“…Fluorescence spectra of rare earth activated materials have potential industrial applications, for example, in solid state lasers (YAG:Nd), in color TV monitors (Y 2 O 2 S:Eu) and in X-ray intensifying screens (LaOBr:Tb) [1,2]. Lanthanide orthophosphates (LnPO 4 ) crystallize in two polymorphic types, the monoclinic monazite type (for Ln = La to Gd) and the quadratic xenotime type (for Ln = Tb to Lu).…”

Ultra-trace method for lanthanide ion determination by selective laser excitation

“…Finally, the high spectral intensity of the dye laser and the ability to efficiently deliver this energy to the small area on the sample that is being observed provides the extraordinary sensitivities that have been demonstrated for laser excitation. The detection limit reported in this paper for erbium by the SEPIL technique is lower than that obtainable by neutron activation (I), inductively coupled plasma emission (2), ultraviolet continuum source excitation of solid state luminescence (3), mercury line source excitation of solid state luminescence (4), and x-ray excited optical luminescence of erbium in YP04 (5). Shand quoted a detection limit of 0.1 gg/g erbium in CaF2 in the case where erbium is positively identified, by employing x-ray excited optical luminescence (6).…”