Investigation of a Metallic Green Tara Buddhist Statue using Neutron Tomography and Multi-Techniques

In the making regulation of ancient metallic Buddhist statues, a sacred consecration practice known as zhuangzang(装藏) is performed, wherein primarily organic objects are deposited inside the statues to represent internal organs or endow them with sacred power. The study of those concealed objects is crucial to uncovering the sanctity of the statues and gaining a deeper understanding of ancient Buddhist practices. Given the irreplaceable nature of ancient artifacts and the inviolability of religious culture, the use of non-invasive and non-destructive techniques is imperative for visual investigation. Neutrons, characterized by high penetration and sensitivity to light elements, enable enhanced detection of such organic materials within dense metallic casings. This capability, difficult to achieve with other techniques, demonstrates significant potential for the bulk analysis of Buddhist statues. In this study, neutron computed tomography (CT) is employed to visually investigate a metallic Buddhist statue housed in Guangdong Museum. This approach was complemented by X-ray CT, Raman spectroscopy, and X-ray fluorescence (XRF) analysis. The results uncover a variety of consecrated deposits inside the statue, including an axis wood, precious gems, grains and medicinal herbs, which are in accordance with traditional zhuangzang culture. Furthermore, the manufacturing techniques and certain external features of the statue are also revealed. This study provides scientific evidence for understanding ancient Buddhist culture and demonstrates the considerable utility of neutron techniques for the non-destructive investigation of cultural heritage.