Phosphorus-32 Production by Sulfur Irradiation in a Partially Moderated Neutron Flux by ~32S(n,p)~32P Reaction

摘要

Taking advantage of the fact that some positions for irradiation in the Mark III Nuclear Reactor of the Nuclear Centre of Mexico show neutron fluxes only partially moderated, phosphorus-32 has been produced by irradiating targets of previously purified commercial sulphur, by distillation at 444±2°C under nitrogen atmosphere, dilution of vapours in carbon disul-phide, filtration of the solution through fibreglass, Teflon and cellulose, as well as final crystallization of S_a by CS_2 evaporation. After irradiation during 6 to 20 hours with fast neutron fluxes from 4.5 to 7.4 x 10~(12) n-cm~(-2)-s~(-1), the sulphur target is distilled again at the same temperature, always under nitrogen atmosphere. Once the Pyrex recipient is cooled down to 110±2°C, one air flux is passed through during few seconds, and the ~32P is stuck on the recipient wall. When 25 to 50 ml of concentrated HC1 are added, an acid solution of H_3~32PO_4 is formed. Once this acid solution is diluted and pH fixed to an adequate value, labelled ortophosphoric acid is available to obtain labelled phosphates to be used in biological and agricultural studies. Chemical and radiochemical purity of these substances are almost total. At this stage, till 12 mCi of H_3~32PO_4 have been obtained for S_a, target mass of 5 g. The procedure seems to be so reliable that industrial, periodical production is being planned to start in a few months.