A FILM-BADGE METHOD OF DIFFERENTIAL MEASUREMENT OF COMBINED THERMAL-NEUTRON AND GAMMA-RADIATION EXPOSURES

摘要

A body film-badge dosimeter using Du Pont 502 dental_ film and utilizing a 20 mil cadmium filter, a 20 mil brass filter, and an unshielded area was calibrated by exposure to combinations of thermal neutrons and gamma radiations from the thermal column of a homogeneous reactor and a radium source. A method was devised whereby combined thermal-neutron and gamma-radiation exposures can be differentiated and evaluated. The method of differentiating and evaluating the thermal-neutron exposure is accurate, provided the gamma-ray energy spectrum lies between 0.15 and 10 Mev. The gamma-radiation exposure can be accurately evaluated, provided the gamma-ray energy lies between 0.3 and 3 Mev, a range over which the film-badge response is independent of the gamma-ray energy. Beta-ray exposures, under restricted conditions, can also be roughly evaluated by previously established techniques.