The preparation of anhydrous HF18

Abstract Two methods of preparing anhydrous HF 18 are presented. (1) An oxygen gas stream is bombarded with an α- or He 3 -beam to yield F 18 ; this F 18 remains within the bombardment vessel, being adsorbed almost quantitatively on its inside wall. By occasionally adding a small quantity of gaseous HF into the oxygen stream, the F 18 is eluted by virtue of the rapid isotopic exchange; the HF 18 is caught in a cold trap. (2) Neutron-irradiated Li 2 CO 3 is dissolved in sulphuric acid containing a trace of H 2 SiF 6 ; the F 18 is steam-distilled and then adsorbed by anion exchange resin. The resin is then dried, and the F 18 is eluted with gaseous HF.