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A technique has been developed to produce miniature, high-density capsules of curium-244 oxide contained in three concentric jackets of metallic gold or silver. The final capsules are right circular cylinders, 6.350 mm diameter by (3.18±0.05) mm long, with a minimum density of 11.0 g/cm 3 . Each level of containment was soldered or brazed closed, with the outer surface free of detectable alpha contamination. Fabrication was performed in three separate small cells operated by standard master-slave manipulators. Production capsules have been stored for up to five years without indication of dimensional growth or leakage of radioactive contents. The dimensional stability of the capsules is attributed to the microporous structure of the plated-gold structure which permits helium gas resulting from alpha decay to diffuse through the capsule wall while retaining all radioactive materials.

A sample changer designed to process automatically up to 48 2-cc samples is described. Mechanical drive mechanisms, digital electronics logic, and operational flow diagrams are presented. The changer is an integral part of a system consisting of an x-ray exciting source, a turntable changer, a Si(Li) radiation detector, and a preprogrammed pulse-height analyzer. X-ray fluorescence analysis of a sample allows quantitation of selected trace elements after simple spectral integrations are performed by an on-line microprocessor. Selection of the changer's MIX mode will cause each solution sample to be mixed just prior to analysis, thus insuring that representative tracer concentrations are determined.

Stable tracers are safe, convenient and readily available, but their use entails the need for involved assay techniques. X-ray fluorescence combines the use of stable tracers with the convenience of radioactive quantitation techniques. An automated system has been developed for use in medicine. Its performance and applications are presented.

The use of stable tracers assayed by x-ray fluorescent excitation analysis has proven advantageous over other stable or radioisotopic techniques in a number of clinical and investigative situations. An automated fluorescent excitation analysis system for medical application has developed. Its design parameters and performance are described.