On 14 December 2013 (UTC), China's Chang'E-3 (CE-3) succeeded in landing on the Moon's surface. The CE-3 landing site is in northern Mare Imbrium and several tens of meters away from the rim of a young crater with a few hundred meters in diameter. In-situ measurements of lunar soil around the roving area were conducted from Active Particle-induced X-ray Spectrometer (APXS) onboard Yutu rover. Three relatively young lunar soil samples in the CE-3 landing site were investigated. Previous studies suggested that these samples are a new type of basalt, not discovered yet in previous missions before the CE-3 in-situ measurements. It plays an essential role in promoting the understanding of lunar volcanic history. However, their results are deviated, and thus scrutinizing the data as per our optimized model to derive a more precise result is of necessity. In this paper, we present an optimized model for data analysis based on APXS measurements to derive the major elements concentrations. The optimized model has the advantages of reliability and being independent of calibration by ground standards. The particle size effect is applied in lunar X-ray fluorescence modeling for correction, improving the accuracy in determining the elemental concentrations for the actual measurement. Our results are distinct in the correlation plots by carrying out a comparison with previous lunar regolith samples from Apollo, Luna, and Chang'E-5 missions, indicating that the CE-3 landing site is a new region apart from previous in-situ or laboratory detection prior to the CE-3 measurements. It suggests a kind of young mare basalt with unusual petrological characteristics compared with previous samples and similar geochemical properties of CE-3 landing site and western Procellarum and Imbrium (WPI), with a signature of western Procellarum.

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