Li Liang, Liu Yifei, Chen Longwei, Wang Gong, Liu Ming, Ren Zhaoxing, Zhao Ying, Liu Bingshan, Zhao Guangheng
Technology and Engineering Center for Space Utilization, Chinese Academy of Sciences, Beijing 100094, China.
Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China.
Rev Sci Instrum. 2018 Aug;89(8):083304. doi: 10.1063/1.5037273.
Under ultra-low pressure, an electron beam is generated by the microwave electron cyclotron resonance plasma with a permanent magnet. By means of the Hall coil and Miller ampere meter, two electron current signals at the end of the extraction anode (Ia) and the sample holder (Is) were measured. The influences of discharge power, gas pressure, and accelerating voltage on the electron beam current Is were analyzed. The experimental results indicated that the extracted electron current can reach 75.1 mA at a gas pressure of 1.4 × 10 Pa, an accelerating voltage of 8 kV, and an orifice size of 3 mm in diameter. In order to estimate the focusing properties of the electron beam by the beam-focusing coil, the influence of the coil current on the size of the electron beam spot on the sample holder was presented and discussed. The intrinsic mechanism of electron beam extraction and propagation is revealed by numerical simulation.
