Evaluation of the Radioactive and Noxious Gas Production for the DAPHNE Complex

One of the radiation protection problems usually considered around the accelerators is the radioactive and noxious gas production. In this note such a problem will be examined for the DAPHNE complex in order to establish the precautions to take for ensuring safe working conditions to the staff of the machines and to the other employees of the centre. Air inside the hall housing the machines will be activated by bremsstrahlung and by neutron radiation generated during the operation of the machines. The air irradiation also causes the formation of noxious gases such as ozone and nitrogen oxides and consequently an evaluation of the production of these gases has been also made. The concentration estimations inside the halls of the DAPHNE complex have been made on the basis of the realistic operation conditions of the machines, but conservative assumptions have been adopted in calculations, particularly regarding the values of the saturation activities. The radioactive gases produced inside the buildings housing the machines will be released in the external environment owing to the natural air-change inside the halls or to the forced ventilation. The atmospheric dispersal could expose the workers outside the buildings and the population, up to large distances from the centre, to radiological risks. Therefore, on the basis of a model of atmospheric dispersion the risks due to the releases activities from the DAPHNE complex have been evaluated.