分类： 核科学技术 >> 核探测技术与核电子学 提交时间： 2025-04-06
摘要： In-situ exploration of deep-sea seabed resources is a valuable research direction. Neutron activation-based in-situ exploration methods for seabed polymetallic nodules or crust resources are theoretically feasible because of the high content and high neutron capture cross-section of manganese in these nodules or crusts. However, to date, only a few relevant studies have been conducted. In this study, a prototype Deep-sea In-situ Neutron Activation Spectrometer (DINAS) was designed for resource exploration. Through an analysis of the principles of the spectrometer combined with Monte Carlo simulations of the physical principles and finite element simulations of deep-sea pressure, the structure and fundamental components of the spectrometer were determined. The inner core of the spectrometer comprised three components: a compact neutron generator for neutron production, gamma-ray detectors, and an electronics system. The gamma-ray detector array of the spectrometer consisted of LaBr3 and BGO scintillation crystals coupled with silicon photomultiplier (SiPM) arrays. The electronics system was divided into two modules to implement the SiPM readout and digital signal analysis along the modular design lines. The experimental activation of neutron beamlines at the China Spallation Neutron Source demonstrated the capability of the spectrometer detectors to detect activated gamma rays and showed that the spectrometer achieved an energy resolution of 2.8 % at 847 keV for the LaBr3 detector and 6.7 % at 2.113 MeV for the BGO detector. The laboratory model experiment tested the functionality of the spectrometer prototype, whereas the Geant4 simulation verified the reliability of the Monte Carlo method. The method and prototype proposed in this study proved feasible for the in-situ detection of polymetallic nodules or crusts in deep-sea environments
分类： 物理学 >> 核物理学 提交时间： 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要： The neutron induced reactions on stable Carbon, Nitrogen, and Oxygen isotopes are investigated by using the Talys1.4 toolkit with the default parameters. The neutron incident energy covers a range from 0.20 MeV to 85.00 MeV. For 12C and 14N, the Talys1.4 results agree with the experimental data, while the parameters should be adjusted for 16O. Some En windows are found by comparing the main channels of n + C/N/O reactions, which induce element change. In these En windows, a specific element is activated to a different one while leaving the other element atoms unchanged. The results will facilitate the research of doping effects in organic materials by using neutron activation technique.
分类： 核科学技术 >> 核材料与工艺技术 提交时间： 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要： Instrumental neutron activation analysis (INAA) has been used to determine some chemical element contents (K, Ca, Na, Fe, Zn, Co, Eu, Sb, and Sc) in Traganum nudatum Del (Chenopodiaceae family) consumed in North African rangelands by sheep livestock. Samples were collected from the area of Djelfa in an arid steppe of Algeria. Results show that pasture halophyte had sufficient levels of K, Ca, Zn, and Co to meet the requirements of ruminants. However, it seems that this halophyte shrub had substantial amounts of Na, higher than the critical level established by the National Research Council (NRC). Eu, Sb, and Sc were within the safety baseline of all the assayed elements recommended by the NRC. The high Na content ( 10 g/kg) in this halophytic species requires elevated intake of water by livestock.
分类： 物理学 >> 核物理学 提交时间： 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要： In this study, the activation cross-sections were measured for 232Th(n,2n)231Th reactions at neutron energies of 14.1 and 14.8 MeV, which were produced by a neutron generator through a T(d,n)4He reaction. Induced gamma-ray activities were measured using a low background gamma ray spectrometer equipped with a high resolution HPGe detector. In the cross-section calculations, corrections were made regarding the effects of gamma-ray attenuation, dead-time, fluctuation of the neutron flux, and low energy neutrons. The measured cross-sections were compared with the literature data, evaluation data (ENDF-B/VII.1, JENDL-4.0 and CENDL-3.1), and the results of the model calculation (TALYS1.6).
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