Recent Developments with the GTS-LHC ECR Ion Source at CERN

Linac3 is the first link in the chain of accelerators providing highly charged heavy ion beams for the CERN experimental program. The beams, predominantly lead, are produced with the GTS-LHC 14.5 GHz Electron Cyclotron Resonance (ECR) ion source, operated in afterglow mode. In the framework of the LHC Injector Upgrade program (LIU), several activities have been carried out to improve the GTS-LHC and Linac3 performance, in terms of delivered beam current. The extraction region of the GTS-LHC has been upgraded with redesigned apertures and the addition of an einzel lens, yielding improved Linac3 output. Also, a series of measurements has been performed to study the effects of double frequency heating on the afterglow performance of the GTS- LHC. A Travelling Wave Tube Amplifier (TWTA) with variable frequency and pulse pattern was utilized as a secondary microwave source. The double frequency effect commonly reported with CW operation of ECR ion sources boosting high charge state ion production was also observed in afterglow mode. Lastly, for studies of metal ion beam production, a dedicated test stand has been assembled to characterize the GTS-LHC resistively heated miniature oven performance.