Protection of ionization beam cross-section monitor electronics from radiation damages at INR RAS linac

To measure parameters of accelerated protons beam at the output of INR linear accelerator a residual gas ionization beam cross-section monitor (BCSM), which includes a TV-camera with a CCD-matrix, is used. Interaction of the accelerated beam halo with elements of the Linac vacuum chamber leads to a neutron flux initiation, causing damages and malfunctions of the BCSM digital electronics. To resolve such problems catadioptric optical system (COS) was developed and installed at the Linac. The following describes the general organization of BCSM, COS, the discussion of the radiation background in the Linac hall and under concrete shield, as well as the evaluation of the incident neutron flux and the time of satisfactory performance of the TV-camera.