The mechanical design and development of a Krypton gas target system for the production of Rubidium-81

Abstract

This research project involved the design, development and manufacture of a krypton gas target system for the production of the radioisotope Rubidium-81 at the National Accelerator Centre (NAC). The newly designed system had to be linked to the existing production facilities, which set certain restraints and fIxed parameters to the design approach. The highl'ressure krypton-filled gas target was designed to link up to the existing transport system which is used for the transportation of all targets to and from the target bombardment station and· the hot-cells where processing takes place. Radiation resistant materials had to be selected for the target, as it would be exposed to high radiation doses during bombardment in the target bombardment station. Target cooling aspects also had to be taken into consideration due to the heat generated during bombardment. A cryopump system for transferring the krypton gas from a gas storage reservoir to the gas target and back during loading and unloading was developed. A further development was a system which would retrieve the formed radioisotopes in a water suspension after bombardment. This demanded the design of a set of spray nozzles which were mounted inside the gas target chamber, a suitable water circulating pump and ruters to trap the suspended radioisotopes. Due to the high radiation levels] which are, of course, dangerous to operating personnel, the whole system was constructed inside a hot-cell, and thus required the design of a fully remote control system together with gas monitoring and safety components. The processing system itself required many switching and monitoring opera.tions which ha.ve to be carried out accurately and sequentially and this further demanded making use of a microcomputer control system. Material strengths, manufacturing methods, performance and selection of the VarIOus components in the system were investigated, as well as the respective routine maintenance and repair aspects.