High-voltage negative-ion based injector is under development at Budker Institute of Nuclear Physics. Its essential feature is beam transport from the multiaperture source to a single-aperture accelerating tube through a low energy beam transport line (LEBT). This scheme permits to purify the beam from the co-streaming fluxes of fast hydrogen atoms, gas molecules, cesium vapor. As a result, the loading on the accelerating tube by harmful co-streaming and secondary particles is considerably reduced. It will enable more stable operation of the negative ion beam accelerator.
Experimental study of long-pulsed 0.8 -1.2 A, 85-100 keV negative ion beam formation and transport through the LEBT to the distant calorimeter is described. The parameters of the transported beam were measured in the LEBT center at distance 1.6 m by the movable Faraday cup and at the LEBT exit (at distance 3.5 m from the source) - by the multisection beam calorimeter. The efficiency of beam transport vs various beam and LEBT parameters will be presented and discussed.