1.62A (Ge335) 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 94.16 degrees, corresponding to the Ge335 reflection. Raw data in NeXus format are contained in ECH0034262.nx.hdf. These data were corrected for variable detector response using the information in eff_2024-10-06.cif and vertical heights adjusted according to the table in vertical_offsets_2024-10-06.txt. The angular positions of the detectors were adjusted from the nominal 1.25 degree spacing 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 (ECH0034262_LaB6.xyd) and as a pdCIF file (ECH0034262_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中子粉末衍射谱仪，安装了一款采用Ge115切型的新型单色器。此后不久，研究人员使用封装于直径6mm钒罐内的标准六硼化镧(LaB6)样品采集了本次校准数据。该仪器设置为140°出射角，单色器角度设为94.16°，对应Ge335晶面反射。NeXus格式的原始数据存储于ECH0034262.nx.hdf文件中。我们借助eff_2024-10-06.cif（晶体学信息文件，Crystallographic Information File）中的信息校正了探测器响应的非均匀性，并依据vertical_offsets_2024-10-06.txt中的表格调整了探测器垂直偏移量。我们利用echidna-Apr2018.ang文件，将探测器的角位置从标称的1.25°间隔进行了调整。随后，我们基于Avdeev与Hester（2018）提出的算法，利用重叠测量数据对探测器响应进行了二次校正，最终得到适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（ECH0034262_LaB6.xyd）和pdCIF文件（ECH0034262_LaB6.cif，粉末衍射晶体学信息文件）两种格式提供，其中包含数据采集与处理的元数据。数据处理的详细流程已在上述论文中说明，所用的数据处理程序以Python代码的形式集成于Gumtree软件包中。