Development of a nickel plated aluminum krypton-81m target system

A fully automated system was developed to produce rubidium-81 (81Rb), based on the natKr (p, n) 81Rb reaction. The energy incident on the target was 26 MeV. Only 6 MeV was stopped inside the gas and the remainder was stopped by a specially designed flange. The target body was characterized by its conical shape and its inner walls were chemically plated with 100±10 µm of nickel (Ni). Ni is advantageous as a fairly good conductor of heat whose surface can resist solutions. Additionally, the Ni plated target allowed potassium chloride to dissolve 81Rb, with no further effect on the target body. The system produced 81Rb with a production yield of approximately 4.5 mCi/µA h, which is close to the calculated expected yield of 5.3 mCi/µA h. The system is able to deliver reliable and reproducible radioactivity for patients and can be operated up to 1500 µA h before preventive maintenance is due. Key steps in designing the 81Rb target for selected energy ranges are reported here.