Activities in optical spectrometry included development of programs for calculations on a time-sharing computer, measurement of arc temperatures, applications of the laser probe and the plasma jet, and studies on atomic absorption spectrometry. In x-ray spectroscopy, there were some modifications of equipment, improvements in computation methods, and several applications. Improvements and additions were made to the electron probe analyzer, along with studies on measurement techniques, including nondispersive analysis and computation procedures. The spark-source mass spectrometer was also modified, and a new analog computer has been built and tested for reduction of photographic plate data; applications of this instrument to analyses of pure materials are described. Enrichment methods are being studied for the analysis of pure materials by emission spectroscopy, particularly with an electro-deposition technique. Homogeneity studies and analyses were performed in the development of standard reference materials. (Author).

The report is the fifth in a series of annual progress reports of the Spectrochemical Analysis Section of the Analytical Chemistry Division of the National Bureau of Standards. Briefly discussed is research on the following topics:Optical spectrometry (High-aperture spectrograph, Microanalysis in the DC arc); Electron probe microanalysis (New technique and instrumentation for target current scanning, Color composite X-ray scans); X-ray fluorescence spectrometry; Spark source mass spectrometry (New pump for plate prepump section, Use of 100-mesh grids to remove matrix line broadening, Homogeneity testing of iron in high purity gold SRM 685, Survey analysis of a steel sample, Trace characterization of spark source ion samples of SRM platinum 681); Preconcentration techniques (High purity metals, Ingot iron and steels, Simulated lunar glasses, Ultra-pure liquid reagents).

Spectrochemical research activities, improvements in equipment, and applications, especially to the certification of NBS Standard Reference Materials, are summarized. In electron probe microanalysis, a comprehensive computer correction program for accurate analysis of materials relative to single elements or simple compounds was developed, an improved lithium-doped silicon detector was found to provide increased resolution, and improvements in microprobe instrumentation produced a high level of stability. Studies of procedures for correction of x-ray fluorescence measurements were made, instrumental changes resulted in marked improvement in performance reliability, and new applications were made. In optical emission spectrometry, studies were made of beryllium determination in an air pollution investigation and trace analyses were made of organic materials to parts per billion limits. Methods of pre-concentration of impurities are described for optical emission and isotope dilution spark source mass spectrometric analysis of ingot iron, botanical materials, and high purity reagents. Work on Standard Reference Materials resulted in certification of stainless steel, clays, ferrosilicon, blast furnace irons, white irons, lead bearing metal, and ductile irons. (Author).