Isidore Adler

X-Ray Fluorescence Analysis of the Light Elements in Rocks and Minerals

Recent advances in the x-ray fluorescence analysis of the light elements offer the advantage of speed and an accuracy approaching that of wet chemical procedures In addition to Fe, Mn, Ti, Ca, and K, the elements P, Si, Al, and Mg, previously considered too light to be determined quantitatively, can now be included in the scheme of analysis X-ray fluorescence analysis of these light elements is primarily confined to layers close to the surface, with the attendant problems of particle size, mineralogic history, and absorption differences owing to compositional variation among samples Fusion of the sample with a suitable flux eliminates problems of particle size and mineralogic differences Simple fusion, however, does not eliminate absorption differences due to variation in matrix By introducing into the fusion melt a strong absorber (La2O3) for the light elements, the variation in concentration of absorbing elements in the unknown sample will not materially affect the overall absorption of the fused mass for the elements being determined This permits the use of a single set of standards regardless of the rock type to be analyzed The x-ray fluorescence method has been applied to the analysis of a wide variety of rock types such as granite, diabase, dunite, limestone, dolomite, and phosphate rock, with results that compare favorably with chemical values

Metallic Spherules in Tektites from Isabela, Philippine Islands

Iron-nickel spherules, as much as 0.5 mm in diameter, have been found completely embedded in some philippinites. The spherules consist mainly of kamacite with unidentified pink inclusions. The meteoritic origin of these spherules seems reasonable, suggesting that the tektites containing them were formed by asteroidal or meteoritic impact.

Lunar Surface Chemistry: A New Imaging Technique

Detailed chemical maps of the lunar surface have been constructed by applying a new weighted-filter imaging technique to Apollo 15 and Apollo 16 x-ray fluorescence data. The data quality improvement is amply demonstrated by (i) modes in the frequency distribution, representing highland and mare soil suites, which are not evident before data filtering and (ii) numerous examples of chemical variations which are correlated with small-scale (about 15 kilometer) lunar topographic features.

A Multi-Wavelength Fluorescence Spectrometer*

A basic multi-wavelength x-ray fluorescence spectrometer has been designed and a two-goniometer prototype built. The instrument is of the dispersive type, using separate crystals, Geiger-Muller detectors, and counting circuits. The system, by providing for the simultaneous determination of more than one element, results in economy of testing time and in improved precision. Finally, an application to one type of ore analysis is described.

The detection of sulphur in contamination spots in electron probe X-ray microanalysis

Sulphur has been identified as one of the elements present in the contamination spot which forms under the electron beam in the microprobe. The presence of the sulphur results in a rapid change in intensity measurements causing a loss of observed intensity for elements other than sulphur. The source of sulphur has been traced at least in part to the Apiezon B diffusion pump oil. A comparative X-ray fluorescence study of the Apiezon B and Octoil diffusion pump oils showed substantial amounts of sulphur in the Apiezon B. The Octoil was relatively free of sulphur.