Negative ion beam acceleration and transport in the high voltage injector prototype

A high-voltage negative ion based neutral beam injector is under construction at the Budker Institute of Nuclear Physics. It consists of a negative ion source, a Low Energy Beam Transport section (LEBT), which purifies the beam before acceleration, a multi-electrode single-aperture beam accelerator, a negative ion neutralizer and a magnetic separator with beam energy recuperators. The test stand to study the main injector components, consisting of the negative ion source and LEBT, the high voltage platform and the accelerator with beam transport section was launched in 2019. The initial experiments on the negative ion beam production, acceleration and 180 keV transport were tested. The power load to the acceleration tube electrodes and the data on the transported beam parameters, measured at the several positions and at the beam dump calorimeter are presented. The beam transport efficiency as a function of various ion source and LEBT parameters are presented and discussed.