A lunar sample renaissance

Instrumental Neutron Activation Analysis of Chang'E-5 Lunar Regolith Samples

The Chang'E-5 (CE-5) lunar samples were analyzed nondestructively for more than 40 elements by instrumental neutron activation analysis (INAA) with a strict quality assurance and quality control. Based on the INAA results, some new observations and discoveries were made. Major, minor, and trace elements in CE-5 are very different from those of the Earth and Apollo lunar samples. The rare earth element (REE) pattern indicated that the CE-5 lunar samples are mare basalts with a clear negative anomaly in Eu. Element correlations are a very interesting discovery; for example, the ratios of Ba/La and FeO/MnO in CE-5 are almost identical to those of the Apollo lunar samples. These observations and discoveries will enrich the understanding of the formation and evolution of the Moon.