Identification and characterization of scenarios de natural source, representation of the same ones by means of radiological maps

The National Network of Environmental Radiological Surveillance of the Cuba Republic (NNERS) between their main functions of controlling permanently, from the radiological point of view, the environment in the whole national territory, monitoring, among other indicators, the environmental gamma dose rate. This monitoring is carried out in 18 radiological posts distributed by the whole country that gives us an idea of the atmospheric gamma background of a certain region. The influence of the natural sources scenarios in the measurement of the gamma dose rate, results in the variability of the measurement inside oneself region and even in distances so short as 500 meters the variation can be between the 30 or 40 nGy/h, for that, when we estimate the exhibition dose to which the population is subjected, we would introduce a great error when we take like base the gamma dose rate of the region in study. The study of the environmental gamma background was carried out in Havana City, using a mobile gamma dose rate system, with a high sensibility and a very low time of answer. The used system is able to register in real time the position and the gamma dose rate. The monitoring carries out from an automobile, using an interval of measurement of 10 seconds. The obtained results are classified by measurement ranges, and they were associated to different codes of colors and were showed in a map for a better interpretation and visualization of the same ones. Computer tools were developed for do that. The average value of dose rate in Havana City (taking into account the contribution of the cosmic radiation) is 57,2 nGy/h, similar to the national historical average reported by the NNERS that is of 55,3 nGy/h. The municipality of higher dose rate was Cerro with 61,3 nGy/h, and that of lower value was San Miguel del Padron with 53,9 nGy/h. If we discard the contribution of the cosmic radiation, the dose rate in air in Havana City is below 50% of the world average. (author)