New neutralization method for measuring the secondary electron yield of insulative material
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ORIGINAL PAPER
New neutralization method for measuring the secondary electron yield of insulative material Kaile Wen1,2 · Shulin Liu1,2 · Baojun Yan1 · Yuman Wang3 · Binting Zhang1,2 · Zhiyan Cai1,2 Received: 18 January 2020 / Revised: 2 June 2020 / Accepted: 14 June 2020 © Institute of High Energy Physics, Chinese Academy of Sciences 2020
Abstract Purpose The limitation of the traditional bias neutralization method is proved, and a new neutralization method is proposed to measure the secondary electron yield of insulating materials. Method While measuring the secondary electron yield of an insulating sample using the bias neutralization method, the region of an insulating sample irradiated by an electron beam may not be neutralized, because electrons enforced by the bias are not returned to the proper location. The above-mentioned phenomenon is verified by a simulation. To achieve proper neutralization, we propose a method of moving the electron beam to irradiate the metal sample stage without applying a bias voltage, which generates many low-energy electrons around the insulating sample. Those electrons are automatically attracted to the positively charged region of the insulating sample surface and rejected if enough electrons accumulated on the surface. Result and conclusion The limitation of neutralization of bias voltage was verified by simulation, and the new neutralization method was proved to be effective through experiments. Keywords Secondary electron yield · Measurement · Insulators · Charge neutralization
Introduction While an electron beam with a certain kinetic energy is incident on the surface of a solid material, secondary electrons are emitted from the surface of the material. This phenomenon is called secondary electron emission, and the area over which secondary electrons are emitted is called the secondary electron emitting region. The ratio of the number of emitted secondary electrons to the number of incident primary electrons is the secondary electron yield (SEY). Different applications require materials with different SEY properties. In many situations, the secondary electrons could cause harmful effects, for instance, the microdischarge problem of a spacecraft surface and the electron * Shulin Liu [email protected] 1
State Key Laboratory of Particle Detection and Electronics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
2
University of Chinese Academy of Sciences, Beijing 100049, China
3
School of Physics, Nanjing University, Nanjing 210023, China
cloud problem of the inner surface of high-energy particle accelerator cavities, as well as the reliability and lifespan problems of high-power microwave vacuum devices. However, in other applications, such as electron multipliers and certain types of atomic clocks, candidate materials must have sufficiently high SEYs, and studies of materials with high SEYs are important for these applications. It is difficult to accurately measure the SEY of a material, especially for insulating mat
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