Determination of erbium by using fast neutron induced gamma-ray activation analysis

BackgroundIn the process of nuclear fuel generation, neutron poisons are added to enhance performance of nuclear fuel. Erbium is a common neutron poison, and its content needs to be measured and analyzed during the production of such nuclear fuels. The traditional methods have limited penetration and can only analyze the surface of the samples, unable to penetrate the bulk nuclear fuel materials for internal component analysis. Prompt Gamma-ray Neutron Activation Analysis (PGNAA) is a non-destructive testing technique, which is suitable for detecting large samples.PurposeThis study aims to explore the feasibility of determining the erbium in large samples based on PGNAA technology.MethodsFirstly, a deuterium-tritium (D-T) neutron generator and a high-purity germanium (HPGe) detector were employed to establish a measurement platform. Erbium oxide was selected as the sample, and measurements were conducted utilizing the 815.9 keV peak emitted from the reaction of fast neutrons with erbium. Then, the neutron yield of D-T neutron generator was calculated using copper foil activation and Monte Carlo simulations, and the neutron spectrum at sample position was calculated using Monte Carlo simulation for observing the thermal and fast neutron fluxes. Finally, the calibration curve and mass detection limit were analyzed.ResultsMeasurement results show that the neutron yield of D-T neutron generator is (2.34±0.01)×106 s-1 and the fast neutron flux at sample position is 106 cm-2∙s-1. Analysis results demonstrate that there is a good linear relationship between the 815.9 keV peak counts and the mass of erbium. The mass detection limit for erbium is 28 g. In addition, there is no interference between the intrinsic gamma ray of 238U and the 815.9 keV Er peak.ConclusionsThis study verifies the feasibility of PGNAA technology for the erbium determination, which can be used for further analysis of erbium in nuclear fuel.