Synchrotron radiation from final doublet magnets in CEPC MDI

The Circular Electron Positron Collider (CEPC) is a proposed Higgs factory with center-of-mass energy of 240GeV to measure the properties of Higgs boson and test the standard model accurately. Synchrotron radiation (SR) generated from the final doublet (FD) magnets in the interaction region of CEPC double ring scheme is one of the typical issues. SR photons can contribute to the heat load of the beam pipe and cause photon background to the experiments. Furthermore, the radiation dose can damage detector components. In this paper, SR generated from FD magnets is analyzed when beam is with tails and offset. SR from the dipole leakage field of the FD superconducting magnets is also analyzed and the physics limit is given to protect the detector.