The yield of F-18 from different target designs in the {sup 18}O(p,n){sup 18}F reaction on frozen [{sup 18}O]CO{sub 2}

Abstract

The shortage of oxygen-18 enriched water has encouraged the authors to explore alternate methods of production of fluorine-18 where the recovery of the oxygen-18 enriched target material is extremely efficient. They have recently presented the results from a cryogenic target using carbon dioxide ice as the target. This is similar in design to a water ice target previously described. The amount of material required and the maximum beam current which can be put on the target are a function of the particular design. The effects of target cone length and number of cooling fins have been explored in order to optimize the target design. Three different targets have been used to test these parameters. The three targets are shown. The first was the prototype target with a single heat sink at the rear of the target. The second is a target with several cooling fins and a short cone length which requires less target material. The third is a target with several cooling fins but a longer target length which allows for more efficient cooling of the material. The results from these studies are summarized. This cryogenic target gives extremely efficient enriched target material recovery (>99%) and simplicity of materialmore » transfer. The production yields are similar to those obtained with the oxygen-18 enriched water target at beam currents up to 18 {mu}A (the cyclotron limit, not necessarily the limit of the target design).« less