Wavelength Dispersive X-ray Fluorescence Analysis Research Articles

Provenancing and archaeology of roman millstones from the Mediterranean area

Abstract Roman rotary grain mills in the Mediterranean area are mainly of two styles: hourglass-shaped “Pompeian-style” mills and flatter, cylindrical millstones. Many of these millstones are made of igneous rocks imported to the sites where the mills are found, and they may therefore be important indicators of resource procurement and trade if the source of the rock of manufacture can be traced. Three types of igneous rock were used to make millstones: (1) reddish rhyolitic ignimbrite; (2) leucite-phyric lavas and (3) generally fresh grey vesicular lavas of basic-intermediate composition. Potential source rocks and millstones of all three types of rock were characterized using petrographic examination in thin-section, and chemical analysis for major and 15 trace elements determined by low-dilution fusion wavelength-dispersive X-ray fluorescence analysis. One hundred and forty-six millstones and lavas from archaeological contexts were studied, and 113 of these were successfully assigned to geological sources. Sixteen areas of igneous rocks were used by the Romans for millstone production. These include the basic and intermediate composition grey vesicular lavas of Olot (northeast Spain), Agde (southern France), Volvic and possibly the Le Puy area (central and southeast France, respectively), Vulture (Italy), Etna and Monti Iblei in Sicily, Pantelleria, Sardinia, Ustica, the Aeolian Islands, Nisyros (Aegean), Libya and the Middle Atlas and Rif areas of Morocco. The red rhyolite was quarried at the village of Mulargia in Sardinia, and the leucite-phyric rocks originated on the Italian mainland (including the quarry of Orvieto in Umbria). There is a wide variation in size and style of millstones from individual production centres, and some were exported in unfinished form. Grey vesicular millstones were traded up to at least 820 km from their sources and fall into four mainly separate distributions in the Mediterranean. The Mulargia rhyolite and the leucitites were moved mainly from north to south, were traded further than the grey vesicular rocks and were probably the most desirable types. They are found 1350 and 1500 km distant from their sources, respectively. The millstones were moved mainly by sea, perhaps on grain-collecting ships on outward voyages from Italy to the south and west of the Mediterranean.

Sampling and Data-Taking Strategies in X-Ray Fluorescence Assay of Low S/N Solutions

This project was Initiated for the purpose of demonstrating the feasibility of on-line x-ray fluorescence (XRF) analysis for the nondestructive assay of fissile elements (SNM) in reactor fuel reprocessing (dlssolver) solutions, using wavelength dispersive x-ray fluorescence analysis because of its high immunity to the intense gamma emissions of the solutions. A prime objective of this project was the identification and dimensioning of.the parameters critical to XRF assays of high accuracy. The concepts presented herein, though directed primarily to assay of solutions with emphasis on low signal-to-noise conditions and low count rates, are applicable to all assays of solids, slurries, and gases.

A Rapid and Precise Computer Method for Qualitative X-Ray Fluorescence Analysis

AbstractThis paper describes a computer method for wavelength dispersive (WD) qualitative X-ray fluorescence (XRF) analysis. It determines the elements, spectral lines, wavelengths, reflection angles and peak intensities of the first and second order reflections in less than half a minute of time using an IBM Series/1 minicomputer. The resolution and precision are significantly better than the energy dispersive (ED) method and when combined with high speed computer recording the speed is comparable.

X-Ray Fluorescence Capabilities for Uranium Ore Analysis

Comparable uranium sensitivities and detection limits can be obtained by either energy- or wavelength-dispersive x-ray fluorescence (XRF) analysis of L x-rays, and by wavelength-dispersive analysis of M x-rays. XRF methods are more sensitive than 252Cf neutron-induced γ-ray analysis or direct photon analysis of rapid-equilibrium uranium daughters. A laboratory method is demonstrated for quantitative uranium determination in unknown geological matrices without using ore standards.

The accurate determination of major components in Ga xSe y by means of instrumental neutron activation

The various phases of the major component analysis of Ga xSe y by means of instrumental neutron activation were examined. The overall uncertainty for each element was of the order of 0.1% of the final concentration, and no indication of systematic error was found between neutron activation analysis and the comparative method, i.e. wavelength-dispersive X-ray fluorescence analysis. The pronounced reduction in the overall uncertainty was made possible by an improved version of a NaI(T1) detector (scintillation chamber) and by rotation of the samples during irradiation.