Effects of secondary electron emission on high-precision intensity measurements of proton

Accurate measurements of an intense high energy proton beam are generally disturbed by high energy proton induced secondary electron emission. In the present work, a compensation coaxial Faraday cup has been designed according to the compensation mechanism for secondary electron emission. The reason of the uncertainty for measuring proton beam intensity has been investigated. It is that the difference between the forward electron emission field and backward electron emission yield from compensation plate. The experiment is carried out at EN 26 accelerator in Peking University to measure the forward and backward electron emission yields from cupper foils penetrated by high energy proton in the energy ranging from 5 MeV to 10 MeV. The ratio of the forward electron emission yield to the backward electron emission yield is 1.3 as high energy proton penetrates a 10 m thick cupper foil. The results are in excellent agreement with the simulation results.