The Chandrayaan-1 X-ray Spectrometer: First results

► Lunar XRF results from C1XS for two A-class solar flares are presented. ► Results are quantitatively derived and expressed as MgO/SiO2 and Al2O3/SiO2 ratios. ► Ground truth data from the Apollo 14 landing site are duplicated in this work. ► Possible discrepancies between XRF and gamma-ray compositions are discussed.