Dosis equivalente de los operadores de medidores nucleares de densidad y humedad debida a la fuente de neutrones, usando detectores pasivos de policarbonato CR-39 TM

Abstract

Neutron sources of nuclear density and moisture gauges (NDMG), are widely used in construction industry. The exposure control to this type of ionizing radiation is not carried out in Ecuador. The aim of the study was to determine the equivalent and effective dose of the neutron source of an NDMG by passive PADC detectors (CR-39TM) and compare them with the permitted limits. The study was experimental. The emission of neutron was evaluated by an NDMG brand (Troxler model 3430) using CR-39TM to identify trace density and calculate the required doses. The efficiency of the CR-39TM was evaluated by comparing two types of Boron converters (pill vs. adhesive tape) and selecting the most efficient one. Eleven detectors were assembled, using adhesive tape and cadmium foil, and located in different positions simulating the exposure of an operator. The study determined that the average densities of traces identified with boron pill vs. adhesive tape were not statistically different (p value> 0.05). The most efficient converter was used for lower cost reason, the adhesive tape. The highest equivalent dose was for the hand in contact with the equipment (17.04 ± 2.04μSv/h) and the lowest for the face with the operator standing (4.12 ± 0.49μSb/h). The "total" equivalent doses and "8 work hour" effective dose were below the permissible limits (199.09 ± 23.89 mSv / year <500 mSv and 18.50 ± 2.22 mSv / year <20 mSv, respectively). In conclusion, the doses emitted by the neutron sources was lower than the permissible limits. However, it is important to measure ionizing neutron radiation that could affect the health of workers exposed at work.