being multiple sclerosis, rheumatoid arthritis, and cancer. The long-range hope of researchers is that a way be found to manipulate the immune system so as to be better able to contend with otherwise incurable diseases. Radioimmunoassay is perfectly suited not only to cope with the analytical problems of these investigations, but also to shed some light on the chemical and biological mechanisms of these diseases.
ACKNOWLEDGMENT
The author would like to thank Linda Salvatore for her gracious assistance in the preparation of this paper; also for technical and experimental assistance to thank Sheldon Schlaff and Carl Steinberg.
RECEIVED for review June 23, 1972. Accepted September 8,1972.
Procedure for Quantitative Electron Probe Microanalysis P. W. Wright B. H . P. Melbourne Research Laboratories, P. 0. Box 274, Clayton, 3168, Victoria, Australia Quantitative electron probe microanalysis at the Melbourne Research Laboratories of BHP is applied to many varied investigations. Mineral specimens, sintered ores, refractories, and steel at all stages of production are among the specimens examined. The paper outlines the specimen and standard preparation techniques for electron probe microanalysis. The analysis procedures are discussed; particularly the automatic operation of the X-ray spectrometers and data collection for subsequent computing. A timesharing computer facility is used on-line t o correct raw X-ray data and print-out final analyses. The computer programs, that have been developed in BASIC at MRL, are described. They are compared with programs from other electron probe laboratories. Finally, results of analyses of sulfide minerals and oxides are presented to illustrate the value of quantitative electron probe microanalysis in mineral exploration and steel production.
ELECTRON PROBE MICROANALYSIS has been established as an analytical technique for at least ten years. Any suitably prepared solid specimens can be examined by this technique, which can analyze selected areas as small as a micron in diameter. Regions for analysis are positioned optically under a focused electron beam (
