Analysis of Cosmogenic Radionuclides in Chang’e-1 Gamma-ray Spectrometer Spectra

A method for determination of concentration for some major elements on the lunar surface was introduced by analyzing gamma-ray spectrum produced by cosmogenic radionuclides. The gamma-ray spectra, recorded by Chang’e-1 Gamma-ray Spectrometer (CE1-GRS), consist of gamma-rays released by the decay of natural radioactive elements on the lunar surface (such as K, U, Th), also include that produced by the interaction of surface material (Fe, Si, O) and galaxy cosmic ray (GCR) with shower reaction. According to the GCR flux, the gamma-ray spectra, including the full energy peaks and their peak areas, can be simulated and calculated by Monte Carlo method. Comparing simulation results with measured spectrum by CE1-GRS, the relationship between the full energy peak area and elemental concentration was established. This method could be used for calculating some elements’ average abundance on the moon surface.