Instrumental multielement proton activation analysis of high-purity niobium using both .gamma.-ray and x-ray spectrometry

Abstract

Trace concentrations of nine metallic impurities have been determined simultaneously in high purity niobium by a nondestructive technique based on irradiation of the sample with 12-MeV protons and observation of both theand Xrays from the reaction products with a Ge(Li) and a germanium low energy detector, respectively. The activation of the trace elements is based on (p,n) reactions. The elements determined are: Ti, V, Cr, Fe, Zr, Mo, Hf, Ta, and W. Three other elements, i.e., Pd, Sn and Sb, could have been determined with high sensitivities if at all present. For Ti, V, Fe, Zr, and Mo, this method is more sensitive than other techniques which have been applied to the determination of these elements in niobium excluding solid mass spectrography. Detailed data on possible interferences, precision, and limits of detection are given.Niobium has several special properties enabling its extensive application in various scientific and industrial fields. In the center of interest is the superconductivity exhibited by niobium and its compounds (1). Among the transition elements, the maximum transition temperature occurs for niobium (9.5 °K). Niobium compounds and/or solid solutions, e.g., Nb3Ge, Nb3(Ge,Al), Nb3Sn, Nb-Zr, and Nb-Ti, have become technologically the most important superconducting materials. The highest known superconducting transition temperature, Tc = 22.3 °K for Nb3Ge, was announced recently (2).Because of its suitable nuclear properties, niobium metal finds application as an end-plug in fuel elements for nuclear reactors (3). Niobium is widely used to impart special properties to alloys with regard to their corrosion and fracture resistance, hardness, fabricability, ductility, etc. Many

Procedures for Db chemical characterization in off-line experiments

“…Production cross sections for proton-induced reactions in natural Hf are given [13], which is considered to be the primary reaction channel. Figure 1 shows the gamma spectrum of an aliquot of the initial solution produced through dissolution of the irradiated Hf foil.…”

Niobium and Niobium Compounds

“…Niobium metal is analyzed simply and quickly for metallic and nonmetallic impurities down to the lower ng/g region by glow discharge mass spectrometry (GDMS) [91]. The additional techniques of neutron activation analysis [92,93] or proton activation analysis [94] are used for verification. …”

Sensitivities and interferences in activation analysis of thin samples by means of 25-MeV to 30-MeV protons

“…In the past, charged-particle activation with protons, deuterons, helium-3, and helium-4 have been used mostly for the determination of light elements and trace impurities in refractory metals (1)(2)(3)(4). Most of these works were performed with thick targets, requiring each sample to be irradiated individually and being so far rather irradiation time-consuming.…”