Human iron metabolism has been extensively studied in the past twenty-five years with the radioisotopes iron⁵⁵ and iron⁵⁹. Before the availability of the whole body counter, however, iron absorption studies were performed by the indirect methods of fecal assay of unabsorbed radioiron, and estimation of red cell incorporation of absorbed tracer. The few long-term excretion studies performed required numerous assumptions, since human iron excretion was less well understood. Whole body counting provides a simple and accurate method of measuring the total body retention of administrative tracer iron⁵⁹, thus making absorption and subsequent excretion determinations possible with a single radioiron study. The energetic gamma emissions of iron⁵⁹ permit ready external detection with small quantities of isotope, Normal radioiron distribution is uniform throughout the circulating red cell mass and thus minimize geometry influences on the counting efficiency, 0nly the 45.1 day half-life of iron⁵⁹ limits long term iron turnover studies. Measurements of iron⁵⁹ absorption and long-term body turnover have been under way at Brookhaven National Laboratory for over two years. The present paper outlines some of the results of these studies, and discusses some implications of the method.

Iron containing approximately 0.01 wt. % carbon was quenched from 700°C and irradiated in the BNL reactor at 57°C for various lengths of time. The rate of decay of the Snoek internal friction peak was observed at 57°C after irradiation. After a 4-hour irradiation the rate of decay of the peak was one order of magnitude faster than the rate of decay in an unirradiated specimen. Longer irradiation times up to 48 hours caused no further acceleration of the decay rate. This observation implies that in the irradiated specimens there are ten times more precipitation nuclei than in the unirradiated specimens. This is confirmed by electron microscope studies which also show a factor of ten greater concentration of precipitate particles in specimens irradiated for 5 hours at 57°C as compared to an equivalent unirradiated specimen. Electron microscope studies also show that longer irradiation times do not increase further this number of precipitates. Although these experiments clearly demonstrate the enhancement of nucleation by neutron irradiation, it is not known why the incipient nuclei created by irradiation times of longer than 5 hours do not form observable precipitate particles.

The alternating-gradient proton synchrotrons at CERN and Brookhaven are very similar in size, design and in their experimental use. For this reason, collaboration between the groups at CERN and Brookhaven has been close throughout the history of these two machines. For the most part this has taken the form of exchanges of visits of individual machine designers and of high-energy physicists. By 1962, however, it appeared that the reciprocal flow of information was not adequate and a more formal meeting was arranged. This meeting took place at Brookhaven during the week of September 10, 1962. CERN sent a representative group of machine physicists and high-energy physicists. The meeting was attended also by observers from several American high-energy installations. The discussion covered a wide range of topics, from operating characteristics of the machines themselves to future trends in design of experimental equipment. Plans for beam ejection were presented, techniques were described for better use of secondary beams from internal targets, progress was summarized on dc and rf particle separators. and future trends in neutrino experimentation were predicted.

During a visit to Professor H.G. Harb at the University of Wisconsin, it was apparent that he had succeeded in obtaining fresh, clean chemisorptive layers of titanium by sublimation and chat that this could be adapted into an effective high vacuum pump. Two previous techniques of obtaining a chemisorptive layer of titanium, namely catholic sputtering and evaporation from the liquid droplet, have been extensively investigated and reported. Each of these seem to have inherent difficulties in stability and continuity of operation that appear to be eliminated or effectively reduced by the sublimation procedure. A development program was started at Brookhaven National Laboratory to investigate the possibilities of each sublimation of titanium as opposed to evaporation from the liquid.