Design and Optimization of Thermosyphon Batch Targets for Production of F-18

Abstract

F-18 is a short-lived radioisotope commonly used in Positron Emission Tomography (PET). This radionuclide is typically produced through the O-18(p,n)F-18 reaction by proton bombardment of O-18-enriched water. Thermosyphon batch targets have been proposed as a means to increase F-18 production due to their enhanced heat rejection capabilities. These boiling targets have been operated with up to 3.2 kW of beam power with manageable O-18 enriched water volumes. The purpose of this research project has been to develop computational methods which can be used to design new targets with enhanced production capabilities. The computational methods developed in this work were used to design a low power thermosyphon production target for the Duke Medical Center cyclotron. This design was modeled to be range thick, and operate within the desired margins for beam powers in excess of 1 kW, the operating limit of the Duke cyclotron. A sensitivity analysis of the computational methods was performed which indicated the model is most sensitive to the boiling and condensing heat transfer coefficients. Even with a high uncertainty in these coefficients, the target should still operate well within the desired margins.