RESUMO
X-ray transmission imaging (XRT) is widely used for sorting materials. However, conventional single-energy and dual-energy X-ray systems have poor ability to discriminate between materials with similar atomic number (Z), and the count rate of available multi-energy XRT detectors could not support high-speed industrial applications. This paper presents the design of a detector that can potentiality achieve high-speed multi-energy X-ray imaging using Geant4 simulations. This detector consisted of five detection layers (with three scintillator materials: CsI, GOS and CdWO4), two metal filters, which allows X-ray imaging at five energies. Validation simulation showed that the 15% more accurate than a dual-layers detector in the classification of Mg and Al alloys.
RESUMO
In this work, prompt gamma ray neutron activation analysis technique was used to monitor the REEs saturation in resin. A facility consisted of a D-T neutron generator, a BGO detector and a 3He detector was established and applied to analyze REEs (Gd and Sm) samples. Neutron self-shielding effect was also corrected. The enriched Gd and Sm in resin were close to saturation at about 400 min. The results showed a satisfactory agreement with the XRF tests, which demonstrated that PGNAA was sufficient for monitoring REEs saturation in resin.
Assuntos
Resinas de Troca Iônica , Metais Terras Raras , Estudos de Viabilidade , Análise de Ativação de Nêutrons/métodos , NêutronsRESUMO
A DT neutron source-based prompt gamma ray neutron activation (PGNAA) facility for bulk sample analysis was designed and developed in this research. The aqueous samples containing chlorine and boron with known concentration were determined for the calibration curve by the facility. The neutron self-shielding effect was corrected by internal standard method. The minimum detectable concentration of boron and chlorine are 1.37 ± 0.42 and 12.51 ± 3.80 mg/L, respectively. Finally, five mixture aqueous solution samples were measured for the facility performance test. The maximum relative deviation of boron and chlorine are 4.49% and 5.32% respectively.
Assuntos
Terapia por Captura de Nêutron de Boro , Boro , Boro/análise , Cloro , Raios gama , Nêutrons , ÁguaRESUMO
The traditional library least squares approach (LLS) is affected by the inconsistency of the statistical uncertainties of different channels in a gamma spectrum, which leads to large fluctuations in the analysis results. This work proposes a weighted library least squares approach (WLLS) that uses the square root of the count to weight the regression objective function and has implemented a verification experiment based on Prompt Gamma Neutron Activation Analysis (PGNAA). The results showed that, after weighing using the square root of the count, the fluctuation level of statistical uncertainty in the spectrum was reduced from 44.34 to 2.25. After the analysis of the WLLS approach, the average standard deviation of the results was reduced to at least 0.37 times that of the LLS approach.
Assuntos
Análise dos Mínimos Quadrados , Raios gama , Análise de Ativação de NêutronsRESUMO
In the research, the Nuclide Identification and Quantitative Analysis System (NIQAS) for the identification of hazardous goods was designed and optimized by MCNP simulations. With the D-T neutron generator and HPGe detector set as the core of device, the modules, including reflector, moderator and shielding, etc., were optimized by a Signal-to-Noise Ratio (SNR) evaluation method. Moreover, the NIQAS device was set up for measuring the hazardous goods, and the type identification was discussed based on the established logical decision. Finally, a Graphical User Interface (GUI) was designed and the minimum detection time was further investigated.