Jiang C Y, Tong X, Brown D R, Glavic A, Ambaye H, Goyette R, Hoffmann M, Parizzi A A, Robertson L, Lauter V
Instrument and Source Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6393, USA.
Quantum Condensed Matter Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6393, USA.
Rev Sci Instrum. 2017 Feb;88(2):025111. doi: 10.1063/1.4975991.
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 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 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.
现代散裂中子源产生高强度中子束，其具有宽波长范围，可用于探索从几个原子单层厚到具有多个埋藏界面的复杂原型器件类系统等新型纳米和介观尺度材料。在中子散射实验中，高性能中子偏振器和分析仪对于理解具有新颖功能的系统中的磁性至关重要。我们报告了为橡树岭国家实验室散裂中子源的磁反射计开发的新一代原位极化氦中子偏振分析仪。通过新的光学布局和激光系统，氦极化率达到并保持在84%，而第一代系统为76%。极化率的提高使得对于波长范围为2 - 9埃的极化中子束，透射函数能够在50%至15%之间变化。这一成果带来了一类在探测纳米系统中非常小磁矩方面具有最佳灵敏度性能的新实验，并为其应用开辟了前景。
