使用山嵛酸银标定中子小角散射谱仪的关键参数

Calibration of key parameters for small angle neutron scattering spectrometer by using silver behenate

为了快速标定中子小角散射谱仪的关键参数:速度选择器的选择波长和波长分辨率以及谱仪布局下的Q分辨率,采用实验方法对山嵛酸银粉末的中子小角散射实验数据进行了拟合。首先,确定谱仪布局,包括准直光阑孔径大小、准直长度、样品到探测器之间的距离;其次,在中子小角散射谱仪的机械速度选择器设置在3 000、4 000、5 000和6 000r.min-1 4种不同转速下,测定山嵛酸银粉末的中子小角散射谱;最后,对实验数据进行反演分析。通过分析,计算出该机械速度选择器常数为2 329.2r.m-1.nm,从而得到了4种不同转速所对应的选择波长分别为0.776、0.582、0.466、0.388nm;通过对实验数据的拟合还得到了该速度选择器的波长分辨率(23.75%),以及在此谱仪布局下的Q分辨率曲线。结果表明,使用山嵛酸银粉末的中子小角散射能够较好地标定谱仪的关键参数,从而支持对中子小角散射数据的正确分析和反演。

To calibrate quickly key parameters of a small angle neutron scattering spectrometer,such as selecting neutron wavelengths,wavelength resolution,and the Q resolution under a geometrical layout of the spectrometer,the experiment data of small angle neutron scattering for silver behenate powder were fitted.First,the geometrical layout of spectrometer was chosen including the size of circular source,sample apertures of the collimator,the source-to-sample distance and the sample-to-detector distance.Then,the spectra of small angle neutron scattering on silver behenate were obtained under four different revolving speeds of mechanical velocity selector.Finally,these experiment data were inversed and analyzed.Obtained results show that the velocity selector constant is 2 329.2 r·m^-1·nm,correspondingly,four different selecting neutron wavelengths are 0.776、0.582、0.466、0.388 nm,respectively.The wavelength resolution of the velocity selector is 23.75% by fitting these experiment data and the spectrometer Q resolution curves can be obtained by using the chosen layout parameter and different rotating speeds.It concludes that the key parameters of small angle neutron scattering spectrometer can be achieved by using silver behenate,which supports the exact analysis and inversion for experiment data of small angle neutron scattering.