Investigation of the Internal Structure and Gold-thin Layer of the Gilt-bronze Seated Avalokitesvara Bodhisattva at Anseong Cheonryong Temple through the Non-destructive Analysis

Abstract

Anseong Cheonryongsa, a temple located in Anseong Seoun Mountain, is a part of the second Jogye Order of Korean Buddhism, under the Yongju Temple, and enshrines a gilt-bronze seated Avalokitesvara Bodhisattva. In this study, X-ray fluorescence (XRF) analysis revealed that this statue is composed of Cu-27.2 wt%, Sn-12.6 wt% and Pb-48 wt%. A gamma (γ) ray (Ir-192) image confirmed damage on the backside of the statue, which was later repaired with wood. The XRF analysis and visual observation determined the boundary between the metal and wood in the statue. In addition, results of standard X-ray peak intensity of gold foil and correlation with thickness helped to derive an equation for calculating the thickness of the Avalokitesvara Bodhisattva’s gold foil. It was determined that the gilded chest (21 µm) and face (20.7 µm) of the statue were the thickest sections, the wooden substratum (11.9 µm) was the next-most thick, and the bronze (7.4 µm) was the thinnest layer.