Energy spectra of x-ray emitted from surface of FRP insulator

Energy spectra of X-rays emitted from the surface of the FRP insulator were measured for 3 different positions and compared with those of the vacuum gap between electrodes. Near the anode, the X-ray spectrum was dominated by the monoenergetic electrons. Near the cathode, the spectrum peak shifted to low energy compared with that near the anode. This result showed that a large amount of low energy electrons was generated on the surface of the FRP insulator near the cathode.