Study of pixel damages in CCD cameras irradiated at the neutron tomography facility of IPEN-CNEN/SP

A methodology to investigate damages in CCD sensors caused by radiation beams of neutron tomography facilities is proposed. This methodology has been developed in the facility installed at the nuclear research reactor of IPEN-CNEN/SP, and the damages were evaluated by counting of white spots in images. The damage production rate at the main camera position was evaluated to be in the range between 0.008 and 0.040 damages per second. For this range, only 4 to 20 CCD pixels are damaged per tomography, assuring high quality images for hundreds of tomographs. Since the present methodology is capable of quantifying the damage production rate for each type of radiation, it can also be used in other facilities to improve the radiation shielding close of the CCD sensors.