Nieh Mu-Ping, Yamani Zahra, Kucerka Norbert, Katsaras John, Burgess Darcy, Breton Hugo
Canadian Neutron Beam Centre, Steacie Institute for Molecular Sciences, Chalk River Laboratory, National Research Council Canada, Ontario K0J 1J0, Canada.
Rev Sci Instrum. 2008 Sep;79(9):095102. doi: 10.1063/1.2969254.
Small angle neutron scattering (SANS) instruments typically cover a q (scattering vector) range from 0.001 to 0.6 A(-1). This range in q is achieved through a combination of cold neutrons (lambda>4 A) and a highly collimated beam. However, as a direct result of the unavailability of a cold source at the Canadian Neutron Beam Centre (CNBC), we have resorted to adapting a triple-axis spectrometer to perform SANS measurements. This is achieved through the use of multiple converging incident beams which enhance the neutron flux on the sample by a factor of 20, compared to a single beam of the same spot size. Furthermore, smearing effects due to vertical divergence from the slit geometry are reduced through the use of horizontal Soller collimators. As a result, this modified triple-axis spectrometer enables SANS measurements to a minimum q value (q(min)) of approximately 0.006 A(-1). Data obtained from the modified triple-axis spectrometer are in good agreement with those data from the 30 m NG3-SANS instrument located at the National Institute of Standards and Technology (Gaithersburg, MD, USA).
小角中子散射（SANS）仪器通常覆盖的q（散射矢量）范围为0.001至0.6 Å⁻¹。这个q范围是通过冷中子（λ>4 Å）和高度准直光束的组合来实现的。然而，由于加拿大中子束中心（CNBC）没有冷源，我们不得不采用一台三轴谱仪来进行SANS测量。这是通过使用多个会聚入射光束来实现的，与相同光斑尺寸的单束光相比，这些光束可将样品上的中子通量提高20倍。此外，通过使用水平索勒准直器，可减少因狭缝几何结构导致的垂直发散所产生的拖尾效应。因此，这种改进后的三轴谱仪能够进行最低q值（q(min)）约为0.006 Å⁻¹的SANS测量。从改进后的三轴谱仪获得的数据与位于美国国家标准与技术研究院（马里兰州盖瑟斯堡）的30米NG3-SANS仪器所获得的数据高度一致。
