Laboratory experiments of particle size effect in X-ray fluorescence and implications to remote X-ray spectrometry of lunar regolith surface

Abstract

We performed laboratory experiments to investigate the effect of particle size in X-ray fluorescence (XRF) with respect to interpreting remote X-ray spectrometry. To simulate microscopic roughness of the uppermost surface of lunar regolith, we used powdery specimens of crashed rocks ranging 25 to 500 μm in size and flat rock plates for comparison. Our results show that XRF intensities from powdery specimens decrease relative to those from flat plates by up to 50%, especially for larger particle size and at increasing source-to-surface-to-detector angle (phase angle). Corrections should be required for elemental analysis by XRF spectrometry in the SELENE "Kaguya" and other planetary orbiter missions. Copyright © The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS); The Seismological Society of Japan; The Volcanological Society of Japan; The Geodetic Society of Japan; The Japanese Society for Planetary Sciences; TERRAPUB.