Abstract Alpha Particle X-ray Spectrometer (APXS) was one of the scientific experiments on-board the Pragyaan rover of the Chandrayaan-2 mission to Moon, with the objective to determine the elemental composition of the lunar surface near the landing site in the south polar region of the Moon. APXS estimates the abundances by measuring the characteristic X-ray lines of the constituent elements present in the target surface, when irradiated by the onboard Cm-244 radioactive source. X-ray spectral measurement in the energy range of 0.8–25 ​keV with an energy resolution of ~ 135 eV at 5.89 ​keV enables APXS to detect all the major rock-forming elements, such as Na, Mg, Al, Si, Ca, Ti, and Fe. This paper describes the calibration of APXS as an X-ray spectrometer, provides a procedure for quantitative estimation of elemental concentrations based on the measurements of standard geochemical reference materials and provides the detection limits of the major elements. It is shown that, following this procedure, the concentration of the major elements in any sample can be determined with typical accuracy of better than 10% of the actual value.

中文翻译：

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Chandrayaan-2 Pragyaan 漫游车上阿尔法粒子 X 射线光谱仪 (APXS) 的地面校准：一种经验方法

摘要 阿尔法粒子 X 射线光谱仪 (APXS) 是月船 2 号登月任务的 Pragyaan 漫游车上的科学实验之一，目的是确定南部着陆点附近月球表面的元素组成。月球的极地地区。当被机载 Cm-244 放射源照射时，APXS 通过测量存在于目标表面的组成元素的特征 X 射线线来估计丰度。X 射线光谱测量能量范围为 0.8-25 keV，能量分辨率为 ~ 135 eV，5.89 keV 使 APXS 能够检测所有主要的岩石形成元素，如 Na、Mg、Al、Si、Ca 、钛和铁。本文描述了 APXS 作为 X 射线光谱仪的校准，提供了一种基于标准地球化学参考材料的测量值定量估计元素浓度的程序，并提供了主要元素的检测限。结果表明，按照此程序，可以以优于实际值 10% 的典型准确度确定任何样品中主要元素的浓度。