External gamma radiation exposure at the INR Pitesti site

The environmental monitoring activities performed by the specialized laboratory of Institute for Nuclear Research - Pitesti resulted in a considerable amount of valid data concerning outdoor external gamma irradiation. For many years the basic instrument for external irradiation measurement has been the ionisation chamber. The spectrometers, particularly with Germanium detectors allow the measurement of both energy and flux of terrestrial gamma rays, being useful as instruments for gamma ray exposure radiation. Thermoluminescent dosimeters have been found suitable for integrating terrestrial exposure over one month or more. The cosmic ray contribution to human external irradiation exposure are typically about 30 to 50 percent and is not the object of the present paper. Naturally occurring radionuclides in soil or rock, near the surface of the earth are responsible for a major part of human external exposure. The present paper presents external dose dose rates estimation based on both laboratory and 'in situ' measurements made on INR site as well as external doses integrated by thermoluminescent dosimeters. (Author) 1 Fig., 5 Tabs., 8 Refs