An innovative monochromator shielding is designed and implemented for the cold neutron spectrometers XINGZHI and BOYA operated by Renmin University of China at China Advanced Research Reactor.Via Monte Carlo simulatio...An innovative monochromator shielding is designed and implemented for the cold neutron spectrometers XINGZHI and BOYA operated by Renmin University of China at China Advanced Research Reactor.Via Monte Carlo simulations and careful mechanical designs,a shielding configuration has been successfully developed to satisfy safety requirements of below 3μSv/h dose rate at its exterior,meanwhile fulfilling space,floor load and nonmagnetic requirements.Composite materials are utilized to form the sandwich-type shielding walls:the inner layer of boron carbide rubber,the middle layer of steel-encased lead and the outer layer of borated polyethylene.Special-shaped liftable shielding blocks are incorporated to facilitate a continuous adjustment of the neutron energy while preventing radiation leakage.Our work has demonstrated that by utilizing composite shielding materials,along with the sandwich structure and liftable shielding blocks,a compact and lightweight shielding solution can be achieved.This enables the realization of advanced neutron scattering instruments that provide expanded space of measurement,larger energy and momentum coverage,and higher flux on the sample.This shielding represents the first of its kind in neutron scattering instruments in China.Following its successful operation,it has been subsequently employed by other neutron instruments across the country.展开更多
该研究是973计划“高通量中子散射在凝聚态物质磁相互作用方面的前沿研究”的研究- “三轴中子散射谱仪的建造及凝聚态物质中磁相互作用的中子散射研究中期报告”（2012CB 821401）的中期报告.主要进展包括3个部分.首先,我们基本搭建完...该研究是973计划“高通量中子散射在凝聚态物质磁相互作用方面的前沿研究”的研究- “三轴中子散射谱仪的建造及凝聚态物质中磁相互作用的中子散射研究中期报告”（2012CB 821401）的中期报告.主要进展包括3个部分.首先,我们基本搭建完成了“翠竹”热中子三轴谱仪.其次,我们在铁基自旋动力学方面取得了-些重要进展,包括B a Fe2 -x N ix A s ,中的量子临界性质和低能自旋激发谱的演化,铁基超导体自旋序来源的总结以及L i缺陷对L iF e A s性质的影响.最后,在理论方面,我们提出了一种独特的铁基超导理论,对二维阻挫系统中的金属-绝缘体相变也进行了讨论.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12004426,U2030106,and 12304185)the National Key Scientific Instrument and Equipment Development Project of NSFC(Grant No.11227906)the National Key R&D Program of China(Grant No.2023YFA1406500)。
文摘An innovative monochromator shielding is designed and implemented for the cold neutron spectrometers XINGZHI and BOYA operated by Renmin University of China at China Advanced Research Reactor.Via Monte Carlo simulations and careful mechanical designs,a shielding configuration has been successfully developed to satisfy safety requirements of below 3μSv/h dose rate at its exterior,meanwhile fulfilling space,floor load and nonmagnetic requirements.Composite materials are utilized to form the sandwich-type shielding walls:the inner layer of boron carbide rubber,the middle layer of steel-encased lead and the outer layer of borated polyethylene.Special-shaped liftable shielding blocks are incorporated to facilitate a continuous adjustment of the neutron energy while preventing radiation leakage.Our work has demonstrated that by utilizing composite shielding materials,along with the sandwich structure and liftable shielding blocks,a compact and lightweight shielding solution can be achieved.This enables the realization of advanced neutron scattering instruments that provide expanded space of measurement,larger energy and momentum coverage,and higher flux on the sample.This shielding represents the first of its kind in neutron scattering instruments in China.Following its successful operation,it has been subsequently employed by other neutron instruments across the country.
文摘该研究是973计划“高通量中子散射在凝聚态物质磁相互作用方面的前沿研究”的研究- “三轴中子散射谱仪的建造及凝聚态物质中磁相互作用的中子散射研究中期报告”（2012CB 821401）的中期报告.主要进展包括3个部分.首先,我们基本搭建完成了“翠竹”热中子三轴谱仪.其次,我们在铁基自旋动力学方面取得了-些重要进展,包括B a Fe2 -x N ix A s ,中的量子临界性质和低能自旋激发谱的演化,铁基超导体自旋序来源的总结以及L i缺陷对L iF e A s性质的影响.最后,在理论方面,我们提出了一种独特的铁基超导理论,对二维阻挫系统中的金属-绝缘体相变也进行了讨论.
