Design of shielding doors for an electron accelerator of energy 2.2 MeV

This paper presents the principles and calculation methods in design of shielding doors for an electron accelerator with maximum energy of 2.2 MeV and maximum beam intensity of 25 mA. The steel slab needed for shielding door of radiation hall was calculated of 12 cm in thickness. And several thickness values for shielding door of accelerator hall were provided to accommodate different beam losses. To facilitate casting, the two doors were both built with steel slabs of 20 cm in thickness. Under full power operation of the accelerator, the exposure rate by the shielding doors outside the halls were measured as follows: 4.1 x 10-9 C·kg-1·h-1 by the lower edge of the shielding door of accelerator hall; 11.6 x 10-9 C·kg-1·h-1 by the lower-middle edge of the shielding door of radiation hall and 10.6 x 10-9 C·kg-1·h-1 by its lower lateral edges