Implantation and Release of Krypton with Copper Foils

A system and a method providing high-efficiency implantation and release of Kr ions in metal foils have been developed. Implantation and release measurements were performed with a static mass spectrometer. Efficient implantation/retention of rare-gas isotopic ions in a target and their subsequent efficient volatilization from the target is the first of two central requirements for developing an ultrasensitive (10 parts per trillion) method to determine the isotopic content of rare gases. In a number of initial Kr ion implantation runs in Cu, with subsequent volatilization of the implanted Kr by heating, implantation/release efficiencies averaging about 52% were observed. This low value was determined to be due to only partial interception of the Kr ion beam by the target. With modifications to the target assembly, mass spectrometer, and target size, the efficiencies for implantation/release of Kr in Cu were raised to essentially 100%. These efficiencies meet the first requirement for developing this method