STUDIES ON MEVVA ION-SOURCE

This article reports the research results of a MEVVA ion source. The s tructure and working mechanism of the source are briefly described. In order to further upgrade the source's operating function, we have sys tematically studied the circuit characteristics and the cathode struct ure of the source. Thus, the time characteristic of the extracted beam current has been improved and the continuous operating lifetime of th e source has been greatly prolonged. The typical working parameters ar e: the high voltage trigger pulse voltage of the cathode is 12 kV, the trigger pulse width is 20 mu s, the extracted beam pulse width is 250 mu s, and the pulse repetition rate is 1-5 pps. At an extraction volt age of 30 kV and an are voltage of 100, 250, and 200 V, respectively, the extracted beams intensity are 290, 300, and 310 mA for Al, Fe, and Cu cathode material. (C) 1998 American Institute of Physics.