Experimental validation of XRF inversion code for Chandrayaan-1

Abstract

We have developed an algorithm (x2abundance) to derive the lunar surface chemistry from X-ray fluorescence (XRF) data for the Chandrayaan-1 X-ray Spectrometer (C1XS) experiment. The algorithm converts the observed XRF line fluxes to elemental abundances with uncertainties. We validated the algorithm in the laboratory using high Z elements (20<Z<30) published in Athiray et al. (2013). In this paper, we complete the exercise of validation using samples containing low Z elements, which are also analogous to the lunar surface composition (ie., contains major elements between 11<Z<30). The paper summarizes results from XRF experiments performed on Lunar simulant (JSC-1A) and anorthosite using a synchrotron beam excitation. We also discuss results from the validation of x2abundance using Monte Carlo simulation (GEANT4 XRF simulation).