In this paper, the evaluation of a preliminary design of a PGAA （prompt gamma activation analysis） facility based on Monte Carlo simulations is presented and discussed. The implementation of the PGAA method at the C...In this paper, the evaluation of a preliminary design of a PGAA （prompt gamma activation analysis） facility based on Monte Carlo simulations is presented and discussed. The implementation of the PGAA method at the CDTN （nuclear technology development centre） would increase the applications of the TRIGA reactor. The preliminary design is based on a quasi vertical hollow cylinder （called neutron extractor） in the reactor pool to extract the neutron flux. This study evaluates the neutron flux in the upper position of the cylinder in the suggested position of the samples to be analyzed by the PGAA. The calculations of the radioactive capture reaction rates and of the detection limits for some isotopes were performed. Through all these calculations, the feasibility of the application of the PGAA method at the IPR-R1 installations was evaluated. According to the obtained results, it can be concluded that is possible to apply the PGAA method at the IPR-R1 reactor, even with its design restrictions.展开更多
The objective of this study is to find out, to what extent the geochemical characteristics of lapis lazuli can be utilized in respect to its provenance. A wide range of variables is taken into consideration depending ...The objective of this study is to find out, to what extent the geochemical characteristics of lapis lazuli can be utilized in respect to its provenance. A wide range of variables is taken into consideration depending on the quantity of samples analysed from a specific geological region and the methods applied. In order to provide evidence, a multi-technique analytical approach using μXRF, ESEM, PGAA and PIXE is applied to samples from the most famous deposits of lapis lazuli. Special elements determined as fingerprints are compared in relation to the forming conditions obvious in textural features. The results and statistical output allow a differentiation that enables an optimized local classification of the blue stone. An absolute requirement for all geo-tracing performed on blue colored cultural objects of unknown provenance is awareness of the limits of analysis. The possible sources of lapis lazuli are tested by analysing the blue pigment used as paint on murals and ink on manuscripts from the Silk Road.展开更多
In this paper,computational methods are used to optimize the design of a prompt-gamma neutron activation analysis(PGNAA) system on China Advanced Research Reactor(CARR).Approaches are adopted for obtaining accurate ne...In this paper,computational methods are used to optimize the design of a prompt-gamma neutron activation analysis(PGNAA) system on China Advanced Research Reactor(CARR).Approaches are adopted for obtaining accurate neutron beam parameter and saving the computing time.For the radiation shielding design,the optimizing factors include the cost,weight,volume,machining convenience and background radiation at the detector position.Low background spectrum and high sensitivity are expected.The simulation results,and experiences from international PGNAA community,were used in the design of the CARR PGNAA system.展开更多
文摘In this paper, the evaluation of a preliminary design of a PGAA （prompt gamma activation analysis） facility based on Monte Carlo simulations is presented and discussed. The implementation of the PGAA method at the CDTN （nuclear technology development centre） would increase the applications of the TRIGA reactor. The preliminary design is based on a quasi vertical hollow cylinder （called neutron extractor） in the reactor pool to extract the neutron flux. This study evaluates the neutron flux in the upper position of the cylinder in the suggested position of the samples to be analyzed by the PGAA. The calculations of the radioactive capture reaction rates and of the detection limits for some isotopes were performed. Through all these calculations, the feasibility of the application of the PGAA method at the IPR-R1 installations was evaluated. According to the obtained results, it can be concluded that is possible to apply the PGAA method at the IPR-R1 reactor, even with its design restrictions.
文摘The objective of this study is to find out, to what extent the geochemical characteristics of lapis lazuli can be utilized in respect to its provenance. A wide range of variables is taken into consideration depending on the quantity of samples analysed from a specific geological region and the methods applied. In order to provide evidence, a multi-technique analytical approach using μXRF, ESEM, PGAA and PIXE is applied to samples from the most famous deposits of lapis lazuli. Special elements determined as fingerprints are compared in relation to the forming conditions obvious in textural features. The results and statistical output allow a differentiation that enables an optimized local classification of the blue stone. An absolute requirement for all geo-tracing performed on blue colored cultural objects of unknown provenance is awareness of the limits of analysis. The possible sources of lapis lazuli are tested by analysing the blue pigment used as paint on murals and ink on manuscripts from the Silk Road.
基金Supported by National Natural Science Foundation of China(No.10805077)
文摘In this paper,computational methods are used to optimize the design of a prompt-gamma neutron activation analysis(PGNAA) system on China Advanced Research Reactor(CARR).Approaches are adopted for obtaining accurate neutron beam parameter and saving the computing time.For the radiation shielding design,the optimizing factors include the cost,weight,volume,machining convenience and background radiation at the detector position.Low background spectrum and high sensitivity are expected.The simulation results,and experiences from international PGNAA community,were used in the design of the CARR PGNAA system.
