1.3A (Ge337) calibration data for new Ge115 monochromator installed on Echidna Neutron Powder Diffraction Instrument

In early October 2024 the Echidna neutron powder instrument located at the OPAL reactor, ANSTO, installed a new monochromator with Ge115 cut. The present calibration data were collected shortly afterwards from a standard LaB6 sample in a 6mm diameter Vanadium can. The instrument was set to 140 degrees takeoff angle and monochromator angle 85.08 degrees, corresponding to the Ge337 reflection. Raw data in NeXus format are contained in ECH0034261.nx.hdf. These data were corrected for variable detector response using the information in eff_2024-10-06.cif and pixel vertical positions adjusted according to the table in vertical_offsets_2024-10-06.txt. Deviations from the ideal detector 1.25 degree angular spacing were applied using echidna-Apr2018.ang. The detector response was then recorrected based on overlapping measurements using the algorithm described in Avdeev and Hester (2018) resulting in a 1D pattern suitable for fitting wavelength and peak shapes. This 1D pattern is provided here as a plain table (ECH0034261_LaB6.xyd) and as a pdCIF file (ECH0034261_LaB6.cif) including metadata on data collection and reduction. Details of data reduction are described in the above paper, and the data reduction routines used are included in the Gumtree package as python code.

2024年10月初，位于澳大利亚核科学技术组织（ANSTO）OPAL反应堆的Echidna中子粉末衍射仪安装了一台采用Ge115晶面切割的新型单色器。随后不久，研究人员使用直径6mm的钒样品罐装载标准LaB6样品，采集了本次校准数据。仪器设置为140°探测器出射角，单色器角度设为85.08°，对应Ge337晶面反射。原始数据以NeXus格式存储于ECH0034261.nx.hdf文件中。研究团队借助eff_2024-10-06.cif中的校正信息，对可变探测器响应进行了修正，并依据vertical_offsets_2024-10-06.txt中的表格调整了像素垂直位置。随后通过echidna-Apr2018.ang文件，修正了与理想探测器1.25°角间距的偏差。之后基于Avdeev与Hester（2018）提出的算法，通过重叠测量数据重新校正了探测器响应，得到可用于波长与峰形拟合的一维衍射图谱。该一维衍射图谱以纯文本表格（ECH0034261_LaB6.xyd）和pdCIF文件（ECH0034261_LaB6.cif）两种形式提供，其中包含数据采集与约简的元数据。数据约简的详细步骤已在上述论文中说明，所用的数据约简程序已作为Python代码集成至Gumtree软件包中。