LAUSR

An RF-driven negative-ion source development program has been started at ASIPP-Hefei with a small test equipment, Hefei utility negative ion test equipment with RF source (HUNTER). It is devoted to some crucial issues of the RF-driven negative-ion source, such as the improvement of RF efficiency, the enhancement of the extracted negative-ion current density, and the promotion of the beam qualities. In the initial stage, the HUNTER negative-ion source conservatively adopted a similar structure of the ITER prototype source developed at IPP, Garching. It consists of single or double RF driver on the back side of a plasma expansion chamber, and a negative ion accelerator which is able to extract 120 beamlets up to 60 kV for 10 s. In the first phase operation of the HUNTER-ion source, a low-pressure (0.3 Pa) plasma has been successfully achieved by coupling 46-kW RF input power and different plasma parameters have been measured by using Langmuir probes and optical emission spectroscopy. Besides the negative-ion source, the HUNTER comprises the vacuum vessel, the special cooling system, the power supply system, and the source plasma and beam diagnostic system are also ready for the next phase operation of hydrogen negative ion beam extraction.