New generation high performance in situ polarized 3He system for time-of-flight beam at spallation sources
New generation high performance in situ polarized 3He system for time-of-flight beam at spallation sources
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DOI：
10.1063/1.4975991
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发表时间：
2017-02-01
影响因子：
1.6
通讯作者：
Lauter, V.
中科院分区：
文献类型：
--
作者：
Jiang, C. Y.;Tong, X.;Lauter, V.
现代散裂中子源产生高强度、宽波长的中子束，用于探索新的纳米和介观材料，从几个原子单层到具有多个埋藏界面的复杂原型器件系统。高性能中子偏振器和分析器在中子散射实验中的可用性对于理解具有新功能的系统中的磁性是至关重要的。我们报道了橡树岭国家实验室散裂中子源磁反射仪的新一代原位极化He-3中子极化分析仪的研制。在新的光学布局和激光系统下，He-3偏振达到并保持了84%，而第一代系统为76%。极化的改进可以使波长带为2-9埃的偏振中子束的传输函数从50%到15%变化。这一成果带来了在纳米系统中对非常小的磁矩具有最佳性能的新一类实验，并为其应用开辟了广阔的前景。
Modern spallation neutron sources generate high intensity neutron beams with a broad wavelength band applied to exploring new nano- and meso-scale materials from a few atomic monolayers thick to complicated prototype device-like systems with multiple buried interfaces. The availability of high performance neutron polarizers and analyzers in neutron scattering experiments is vital for understanding magnetism in systems with novel functionalities. We report the development of a new generation of the in situ polarized He-3 neutron polarization analyzer for the Magnetism Reflectometer at the Spallation Neutron Source at Oak Ridge National Laboratory. With a new optical layout and laser system, the He-3 polarization reached and maintained 84% as compared to 76% in the first-generation system. The polarization improvement allows achieving the transmission function varying from 50% to 15% for the polarized neutron beam with the wavelength band of 2-9 Angstroms. This achievement brings a new class of experiments with optimal performance in sensitivity to very small magnetic moments in nano systems and opens up the horizon for its applications.