Target and Its Processing

The common form of the target is the metallic foil, but metals melt at high temperature caused by high beam intensity of the particles. Other forms are oxides, carbonates, nitrates, etc., contained in the aluminum tubes, which are flattened after loading to maximize heat loss. The choice of aluminum is owing to its high melting point. 

Liquid targets are used in the production of many PET radionuclides, particularly 18F and 13N. Fluorine-18 is produced by using a liquid target of lsO-enriched water and so is 13N by using 5 nM ethanol in water. The target volume is small in the range of 3-15 ml under high pressure. Since lsO-water is expensive, it is customary to recover it for subsequent irradiation and the method of recovery is described in the later section. 

Gas targets are used for some PET radionuclides such as UC and 150. A mixture of 14N2 gas and (1%) 1602 gas is used to produce 11C, and a mixture 

---