A target vacuum interlock system for Gammasphere

An interlock system is described that allows volatile targets to be prepared in an evaporator, sealed under vacuum, transported to the γγ-array Gammasphere, and inserted into the reaction chamber for experiments, while maintaining a vacuum better than 10-5torr. The performance of the system is demonstrated for lithium metal targets. A comparison is made between lithium targets covered by a gold evaporation to reduce oxidation and open metal targets transferred in the interlock.