共查询到17条相似文献,搜索用时 109 毫秒
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B对Pb-Mg-Al-B屏蔽功能材料的显微组织与屏蔽性能的影响 总被引:1,自引:0,他引:1
利用立式高频感应炉制备出铸造Pb-Mg-Al-B屏蔽材料,并对其显微组织和屏蔽性能进行了研究。结果表明,随着B的添加,材料组织中AlB2颗粒增多;室温抗拉强度可达105MPa,布氏硬度为160;厚度为20mm、B含量为2.0%(质量分数)的Pb-Mg-Al-B屏蔽材料对能量为250、118和65keV的X射线屏蔽率分别为90.29%、99.22%和97.9%,对γ射线的屏蔽率达到49.75%(137Cs源)和34.21%(60Co源),对中子的屏蔽率高达92.7%,说明屏蔽材料具有强度高、X(γ)射线与中子屏蔽性能优异,具备结构-功能(屏蔽)一体化的特点。 相似文献
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含硼铁精矿粉/环氧树脂复合材料射线屏蔽性能研究 总被引:1,自引:0,他引:1
以我国特有的含硼矿物经选矿后得到的含硼铁精矿粉作为中子吸收体与低粘度环氧树脂E51相复合,制备了一种低成本含硼铁精矿粉/环氧树脂复合屏蔽材料。测试了这种复合材料对慢中子和60Coγ射线的屏蔽性能,确定了满足射线屏蔽性能的含硼铁精矿粉与树脂的最佳配比范围。证明了以含硼铁精矿粉作为原料制备复合射线屏蔽材料是可行的。结果表明,3种配比的复合屏蔽材料其慢中子宏观截面均超过了宏观截面为Σ=0.158cm-1,以B4C为中子吸收体的铅硼聚乙烯屏蔽材料B201。此复合屏蔽材料的宏观截面最大值为Σ=0.1882cm-1,具备较好的慢中子屏蔽能力;对60Coγ射线的线性减弱系数最大值为μ=0.0772cm-1,屏蔽性能介于水和混凝土之间。 相似文献
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硅酸凝胶软体材料以其独特的仿生性在核工业机器人领域具有极大的应用前景,而铅(Pb)则对γ射线具有极好的屏蔽效果。因此,该文基于蒙特卡洛方法,采用MCNP软件,模拟计算了硅酸凝胶/铅复合软体材料在4种常见γ射线源下的屏蔽效果。计算结果表明,该材料对0.4 MeV以下的γ射线屏蔽效率高达98%,可达到保证人体安全的辐射防护水平。试验结果验证了模拟计算射线屏蔽效率的准确性,并较好地保持了硅酸凝胶材料的基础特性。研究结果表明,硅酸凝胶/铅复合软体材料在核与辐射安全领域具有良好的应用前景。 相似文献
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目的 了解国内外乏燃料运输和储存容器中子屏蔽材料的类型,整理分析现有中子屏蔽材料的性能和特点,为应用于乏燃料运输和储存容器的中子屏蔽材料的研发提供一定参考。方法 综述国内外应用于乏燃料运输和储存容器中子屏蔽材料的应用现状,对关键性能进行总结和比较,并提出其研究重点和发展趋势。结果 目前,硼化不锈钢、碳化硼/铝复合材料、硼铝合金、聚合物基复合材料和屏蔽混凝土等中子屏蔽材料已应用于乏燃料运输和储存容器。结论 随着核电厂高燃耗的发展趋势,未来乏燃料运输和储存容器对中子屏蔽材料的性能提出了更严格的要求,建议注重研发屏蔽性能优异、装配更换方便、耐辐照的中子屏蔽材料。 相似文献
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包装物对爆炸物中子检测的影响 总被引:1,自引:0,他引:1
文章概述了目前主要的爆炸物中子检测方法,介绍了用热中子俘获γ射线法(TNA法)检测爆炸物的原理,用模拟实验装置对模拟爆炸物进行了检测,得到了被测物的俘获γ射线能谱。实验装置采用d-D中子管产生2.5MeV的快中子,再经慢化之后得到热中子,并采用多个NaI探测器提高检测效率。着重对TNA法中不同外包装物材料以及多层复合外包装物材料对探测结果的影响进行了探索研究和结果分析,发现铜外壳对γ射线的屏蔽较大程度地降低了检出率,而例如聚四氟乙烯等塑料外壳也可能造成类似的影响。 相似文献
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随着反应堆设计技术的发展,功能/结构一体化屏蔽材料成为一种发展趋势,要求中子屏蔽材料不仅具备中子屏蔽功能,而且可以兼作结构材料。中子屏蔽材料采用一体化设计可大幅简化屏蔽结构,实现屏蔽结构的轻量化和小型化。简述了功能/结构一体化中子屏蔽材料的设计要求和常见的热中子吸收核素。重点阐述了硼钢和具备功能/结构一体化潜力的铝基碳化硼复合材料、含Gd不锈钢、B/Pb复合材料的研究现状及存在问题。最后指出了功能/结构一体化中子屏蔽材料的发展方向。 相似文献
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P. Jagam J.J. Simpson J.L. Campbell B.C. Robertson H.L. Malm 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》1985,239(2):214-220
A detailed study of the events recorded with a 208 cm3 intrinsic germanium γ-ray detector produced by interactions of natural environmental radiation was undertaken. In the first part of this work, the data on events from characteristic radioactivity are analysed to optimise the shielding requirements for reducing the γ-ray background as seen by the detector. A thickness of 15 cm of Pb all around the detector in the laboratory location, or only 5 cm in the underground location at the mine, is found to be sufficient to attenuate the event rates from environmental characteristic γ-rays to less than the event rates from intrinsic contamination of the detector components in the detector assembly. The salt mine is found to be a natural environment low in γ-ray background. 相似文献
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Okuno K 《Radiation protection dosimetry》2005,115(1-4):258-261
In recent years, there has been a need for compact shielding design such as self-shielding of a PET cyclotron or upgradation of radiation machinery in existing facilities. In these cases, high performance shielding materials are needed. Concrete or polyethylene have been used for a neutron shield. However, for compact shielding, they fall short in terms of performance or durability. Therefore, a new type of neutron shielding material based on epoxy resin and colemanite has been developed. Slab attenuation experiments up to 40 cm for the new shielding material were carried out using a 252Cf neutron source. Measurement was carried out using a REM-counter, and compared with calculation. The results show that the shielding performance is better than concrete and polyethylene mixed with 10 wt% boron oxide. From the result, we confirmed that the performance of the new material is suitable for practical use. 相似文献
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《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》1988,267(1):223-230
A shallow 252Cf-HPGe probe used for in situ prompt γ-ray activation of water pollutants is described. A 2.7 μg 252Cf neutron source and a 10% HPGe detector are inserted into a waterproof stainless steel probe, which is designed to be submerged and recovered in field operation. A laboratory test is performed to obtain the neutron flux distribution and prompt γ-ray contribution to the HPGe detector counts from around the submerged probe. The concentrations of toxic cadmium and chlorine in water are determined in the prompt γ-ray spectrum. The detection limit of industrial pollutants and some improvements of the current design are discussed. 相似文献
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《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2007,579(1):363-366
We report on the development of high-sensitivity and compact Compton imaging systems built of large and position-sensitive Si(Li) and HPGe detectors. The primary goal of this effort is to provide improved capabilities in the passive detection of nuclear materials for homeland security. Our detectors are implemented in double-sided strip configuration, which—along with digital signal processing—provides energies and three-dimensional position information of individual γ-ray interactions. γ-Ray tracking algorithms then determine the scattering sequence of the γ-ray, which in turn allows us—employing the Compton scattering formula—to reconstruct a cone of possible incident angles and ultimately an image. This Compton imaging concept enables large-field-of-view γ-ray imaging without the use of a heavy collimator or aperture. The intrinsically high-energy resolution of the detectors used, the excellent position resolution we have demonstrated, both combined with the high efficiency of large-volume detectors is the basis for high Compton imaging sensitivity. These capabilities are being developed to identify and localize potential threat sources and to potentially increase the sensitivity in detecting weak sources out of the midst of natural, medical, or commercial sources. γ-ray imaging provides a new degree of freedom to distinguish between spatial and temporal background fluctuations and compact threat sources. 相似文献