Extraction property of RF ion source

Effects of the geometry parameters of drawing electrode， oscillator plate voltage and extraction voltage on the focusing degree of ion source are measured and the experimental results are analyzed to ensure the quality extraction of the RF ion source. On the condition that the other parameters keep unchanged, the ratio of the outer diameter D to its inner diameter d of the drawing electrode has an optimum value. The increase of D/d is beneficial to the re-focusing of over-focusing ion beam. The length of the drawing electrode is L and the quartz pipe is l longer than the drawing electrode. The increase of l/D leads to the increase of focusing degree and the decrease of extraction beam intensity. Focusing degree rises with the decrease of L/d and the rising tendency slows down when L/d is