Measurement of Secondary Electron Energy Spectra of Polymethyl Methacrylate**Supported by the National Natural Science Foundation of China under Grant Nos U1537210 and 11375139, and the National Key Laboratory of Space Microwave Technology China under Grant No 9140C530101130C53013.

Abstract

We report on a novel and convenient method of measuring secondary electron spectra for insulators in a secondary electron yield measurement system with a planar grid analyzer configuration and a metal mesh probe. In this measurement, the planar grid is negatively biased to force some emitted secondary electrons to return to the sample surface and to neutralize charges accumulated on the sample during the previous beam irradiation. The surface potential of the sample is then measured by use of a metal mesh probe. The grid bias for neutralization corresponding to the zero surface potential is determined based on the linear relationship between the surface potential and the grid bias. Once the surface potential equals zero, the secondary electron spectra of polymethyl methacrylate (PMMA) are studied experimentally by measuring the S-curve and then fitting it to Everhart’s formula. The measurement results show that the peak energy and the full width at half maximum of the spectra are 4.26 eV and 14.06 eV, respectively.