Production of the positron emitter Mn-51 via the Cr-50(d, n) reaction: targetry and separation of no-carrier-added radiomanganese

摘要

In connection with the production of 46.2 rain Mn-51 Na the Cr-50(d, n)-process, several separation techniques such as ion exchange chromatography, solid phase extraction, liquid-liquid extraction and co-precipitation have been investigated; the aim was to separate no-carrier-added radiomanganese from the bulk target chromium. Among the separation systems *Mn-II/Cr-III, *Mn-II/Cr-VI and *Mn-IV/Cr-VI, the latter applying the co-precipitation of *Mn-IV with Fe-III hydroxide was found to be the optimum;, the removal of chromium was rapid and quantitative (remaining content < 0.05%) and the separation efficiency was high (99.3% radiochemical yield of *Mn). For production purposes, a sandwiched pellet of the chemical composition (Al4CrCl3)-Cr-.50 was developed as a new target. This allowed a quick dissolution after irradiation, thus enabling a fast separation of Mn-51 and its production on a MBq scale. A I h irradiation at 3 muA (wobbled beam) over an effective deuteron energy range of E-d = 12.8 --> 7.9 MeV yielded 107 MBq Mn-53. Simultaneously formed nuclides of other elements, such as 110, Na, V-48 and Cr-51 were quantitatively separated using the proposed procedure. Only the shorter-lived radioisotope Mn-52m, formed via the Cr-52(d, 2n)Mn-52m reaction, was present at a low level of 2%, if the enrichment of Cr-50 was 95% (with similar to5% Cr-52). [References: 61]