Patent Number: 058752200
Section: description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A target of metallic rubidium is bombarded by a beam of accelerating charged particles, for instance, protons, and then is melted. Radiostrontium is extracted from the target by sorption on the surface of a sorbing material immersed into the molten metallic rubidium at various temperatures. As the sorbing material, use is made of heat-resistant metals or metallic or silicon oxides which are inert with respect to rubidium, for instance, glass, stainless steel, titanium, nickel, aluminium. The temperature of the sorbing material is selected to be close to the optimum one for the sorption of radiostrontium within the range of from the melting point of metallic rubidium to 220.degree. C. Along with this, the temperature of molten rubidium is selected to be close to the optimum one within the range of from 220.degree. C. to 270.degree. C. EXAMPLE 1 To determine the sorption properties of sorbing materials, they were put into glass weighing bottles and nickel beakers, whereupon liquid rubidium produced from the molten irradiated target was poured therein. All the beakers and bottles were thermostatted in a flow of heated-up helium or by electric heaters at a temperature of 50.degree. C. for as long as 3 hours. As the sorbing material, the following materials were tested: "Thermoxide-34" based on ZrO.sub.2, "Thermoxide-50" based on TiO.sub.2, "Thermoxide-230" based on SnU.sub.2, aluminium oxide, tungsten, niobium, titanium, molybdenum, stainless steel, glass, copper, gold, zirconium. After completing the experiment the liquid rubidium was poured off, the sorbing material was taken out and, by means of a Ge(Li) detector, the content of strontium and rubidium was measured in each specimen. The content of strontium was determined from isotopes Sr-82 (776 keV and 511 keV lines) and Sr-83 (a 763 keV line), and that of rubidium, from isotope Rb-84 (880 and 552 keV lines). The results of these experiments are presented in Table 1. TABLE 1 ______________________________________ Distribution of radiostrontium and rubidium on glass weighing bottles and nickel beakers at 50-57.degree. C. for 3 hours Weight Area of of sor- sorbing bing ma- materi- Area of Sorbing terial, al, bot- Sr-82 Rb-84 material .theta. cm.sup.2 tle, cm.sup.2 Sample % % ______________________________________ ZrO.sub.2 4.1 porous 12.6 Sorbing 74.4 16.9 (activated) material Glass 25.6 1.7 weighing bottle Residue &lt;3 81.3 ZrO.sub.2 0.40 porous 12.6 Sorbing 48.9 24.2 (not ac- material tivated) Glass 38.7 2.6 weighing bottle Residue 12.4 73.2 TiO.sub.2 1.7 porous 10.1 Sorbing 57.6 17.7 (not ac- material tivated) Glass 42.4 5.8 weighing bottle Residue &lt;2 76.5 Titanium 0.056 1.5 6.3 Sorbing 11.3 &lt;0.5 (foil) material Glass 28.7 100 weighing bottle Residue Tungsten 0.37 2.5 10.1 Sorbing 12.7 0.1 (foil) material Glass 44.1 0.6 weighing bottle Residue 43.2 99.3 Stainless 3.9 Sorbing 36 1 steel material (clean non- Nickel 36 3 oxidized beaker foil) Residue 28 96 ______________________________________ Strontium-82 is sorbed on the materials to various degrees, in this case, the yield on porous sorbents exceeds 92%. EXAMPLE 2 Radiostrontium was sorbed on various materials with a smooth surface at hight temperature of liquid rubidium. For this purpose, beakers of various materials were put into the cells of an aluminium block, one edge of the block was heated by electric heaters, and the opposite edge thereof was cooled with water in a passage of the block. The temperature in the cells varied within 125.degree. C. to 308.degree. C. Thus, it was plotted how the sorption depends on temperature for stainless steel, nickel, titanium and glass. The duration of this experiment was 3 hours. The results are presented in FIG. 1. The maximum yield on many materials was reached at 150.degree. C. to 170.degree. C., it amounted, for instance, to 96% for stainless steel at 160.degree. C. There is also a second maximum for the yield of strontium (about 300.degree. C., or higher). However, carring out experiments at such a high temperature involves technical difficulties. At a temperature of 240.degree. C. to 270.degree. C., the sorption of strontium was at minimum. EXAMPLE 3 Radiostrontium was extracted from a target containing molten metallic rubidium by sorption on the surface of a sorbent, the temperature of which was maintained different from that of rubidium. In this case, radiostrontium was sorbed on the surface of various materials, including also on the walls of the target shell made of stainless steel. Two nickel rods used as a sorbent were in turn inserted inside the molten rubidium. The surface area of each rod was 3.8 cm.sup.2, and the area of the inner walls of the target shell was 24.5 cm.sup.2. In so doing, the temperature of the rods was maintained to be close to the optimum one for sorption, and the temperature of the target was maintained to be close to the optimum one for desorption from the walls of the shell. The walls of the target shells were heated to 255.degree.-275.degree. C., and the rod was at the same time cooled to maintain a temperature thereof within 122.degree. C. to 130.degree. C., and these conditions correspond to the minimum and maximum values of sorption for stainless steel and nickel, respectively (FIG. 1). The duration of sorption on each rod was 14 hours. On the surface of the first rod was separated out 79% and, on that of the second rod, 16% more so that in total this made up as much as 95% of Strontium-82 for 28 hours of sorption. Use made of the present invention allows to ensure an improvement in efficiency of the production of radiostrontium and simplify the technology of its extraction when a liquid metallic rubidium target is used, through a sorption extraction of radiostrontium from rubidium.