Commissioning of the SEM-Grid Monitors for ELENA

ELENA is a compact ring for cooling and further deceleration of 5.3 MeV antiprotons delivered by the CERN Antiproton Decelerator. It decelerates antiprotons to a minimum energy of 100 keV, creating special challenges for the beam instrumentation. These challenges have been addressed by an extremely sensitive SEM-Grid monitor which is also compatible with the UHV requirements of ELENA. Since November 2019 ELENA’s H⁻ ion source has been used to test the SEM-Grid monitors and since July 2020 the monitors have been used to commission the ELENA transfer lines. In this paper a summary of the features of the SEM-Grid will be given, and an overview of the commissioning activities. A technique for testing the integrity of an inaccessible pickup wire will also be described.