Nano-sized Scandia doped dispenser cathode with annular shape for the hollow electron lenses for CERN high luminosity LHC project

The Large Hadron Collider (LHC) is the world largest and most powerful accelerator for high energy physics. The High Luminosity LHC project (HL- LHC) foresees the construction and installation of important upgrades to increase the efficiency of the LHC machine. Hollow Electron Lenses (HEL) are one of the most promising methods being considered to control the beam halo and to improve the beam collimation system for HL-LHC. The source of the HEL is an annular shaped cathode which delivers a total current up to 5A. We developed a nano-sized Scandia doped dispenser cathode much smaller in size than the previously used B-type dispenser cathodes. The tests demonstrated that this cathode fulfils the specifications and can supply 5A full Space Charge Limited (SCL) current at a true temperature of about 850°C.