Application Progress of Non-Destructive Spectroscopy on Conversation of Cultural Relics

Non-destructive spectral technologies are important methods of information extraction of cultural relics, which can obtain the relevant historical and artistic information on cultural relics in situ, identify the conservation and damage status of cultural relics, and traces the previous restoration. These technologies provide a scientific basis for the assessment of cultural relic conservation conditions, the discussion of disease mechanisms, the research of load information, and the exploration of production materials and craftsmanship. The application of X-ray fluorescence spectroscopy (XRF), laser-induced breakdown spectroscopy (LIBS), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy (RS), infrared spectroscopy (IR), diffuse reflectance spectroscopy (DRS), multispectral (MSI) and hyperspectral imaging (HSI) techniques for non-destructive analysis of cultural relics were presented. Because of the different types, sizes and preservation status of cultural relics, portable and fixed instruments have their characteristics in the non-destructive analysis. Portable and micro-XRF can perform qualitative and quantitative analysis of cultural relics, and Macro-XRF can analyze multi-layer structures and obtain elemental distribution and hidden information of imaging patterns. LIBS can detect low atomic number elements such as lithium and carbon that cannot be detected by XRF and conduct depth and profile analysis of cultural relics. XPS can get the chemical state and elements content on the samples surface. RS can identify the phase composition of cultural relics, confirm the composition and deterioration of cultural relics, and evaluate the protective effect. Resonance Raman spectroscopy is sensitive to aromatic compounds with RS activity and can analyze organic dyes on textiles and paper. Surface-enhanced Raman spectroscopy can identify spectral peaks that conventional RS cannot identify. In infrared spectroscopy, the application of near-infrared spectroscopy has been expanded from organic to inorganic cultural relics. IR reflection spectroscopy can compensate for the deficiency of IR absorption spectroscopy, and it has been used in the research of color painting craftsmanship, surface deterioration layer of cultural relics, and analyzing the multi-layer structure of paint layer. DRS has unique advantages in pigments and dye analysis. MSI and HSI have the characteristics of the integration of spectrum and image, which can perform qualitative, quantitative and localization analysis on the study area. They have been used in the restoration, extracting hidden information and identifying cultural relics. Each spectrum has its characteristic and limit in the test function of cultural relics. In order to obtain comprehensive information heritage as nondestructively as possible, elemental and phase structure analysis, compositional analysis and imaging technology are often used together, combined with metrology and algorithm analysis, to improve the detection results and expand the application scope of non-destructive technology. Finally, the development prospect of non-destructive spectroscopy technology has prospected.