Reactor IPEN/MB-01 dosimetry using TLDs

Abstract

This paper is a preliminary study on the use of reactor IPEN/MB-01 as standard radiation source for mixed field dosimetry studies. As a first step on this attempt, simulations and experiments, evaluating the neutron and gamma field distributions, were performed and compared. TLDs are widely employed in dose measurements and the TLD 100 / TLD 700 pair conforms with ICRU recommendations for mixed field dosimetry. In this study, TLD irradiations were performed in the IPEN/MB-01 nuclear reactor. IPEN/MB-01 reactor is zero power reactor widely used to perform reactor physics experiments. Its neutron flux distribution is well known for a variety of reactor core configurations. However, the photon fluxes are unknown. A series of experiments with TLD 100 and TLD 700 were performed for two different core configurations (rectangular and cylindrical with a central flux trap). Simulations with MCNP5 for these two configurations were also done, and neutron and gamma fluxes distributions along the core were computed. The responses of TLD 100 and TLD 700 were compared with simulated fluxes and showing a good agreement between them. This paper presents the results of the experiments done so far given the status of the study under way in order to couple IPEN/MB-01 and TLD 100 / 700 pair into a mixed field calibration methodology.