“…Among them, X-ray nondestructive techniques play an important role, e.g., X-ray computed tomography (Fulladosa, Santos-Garc es, Picouet, & Gou, 2010;Garcia-Gil et al, 2014;Santos-Garc es, Muñoz, Gou, GarciaGil, & Fulladosa, 2014), X-ray absorption spectroscopy (Fulladosa, Muñoz, Serra, Arnau, & Gou, 2015;Prange, Birzele, Hormes, & Modrow, 2005), X-ray dark-field imaging (Nielsen, Lauridsen, Christensen, & Feidenhans'l, 2013;Schulz et al, 2010), X-ray coherent scatter imaging (Lakshmanan et al, 2014), X-ray Reflection Tomography (Samson, Mizusawa, & Sakurai, 2011), energy dispersive X-ray fluorescence (XRF) (Tiwari, Sahu, Bhangare, Ajmal, & Pandit, 2014), X-ray diffraction microtomography (Artioli et al, 2010), small-angle X-ray scattering (Bandyopadhyay & Ray, 2011;Xu, Shi, & Wang, 2013). How to identify the low density materials with low-Z elements attracts the concerns from the researchers in medicine, biology, material science, food industry.…”