ИСТИНА

A 100-kilometer circular electron-positron collider (CEPC) is expected to be built in China in the near future. With an energy interval of 91 to 360 GeV, the CEPC will enable detailed studies of Z, W+, W−, ZH, and t¯t production. Both the scientific program and the technological side of this project are described in detail in the Conceptual Design Report (CDR, 2015, 2018) and the Technical Design Report (TDR, 2023). However, it should be noted that although the TDR discusses the various sources of secondary electrons that generate the dangerous electron cloud effect, it does not mention another important source of secondary electrons. This source involves quantum field emission of electrons activated by the electric self-field of the positron beam. This report provides numerical estimates of the magnitude of emission current in CEPC collimators. The analysis uses the exact solution previously found for the 2-D problem of fields of a bunch of charged particles between parallel conducting planes, taking into account the effect of mirror charges. The influence of these emission electrons on the stability of the positron beam is also discussed.