Study On Irradiation Sterilization Of Tomb Murals

Sterilization and protection of tomb murals is an important method to perpetuate their historical,artistic,scientific,social,and cultural values.The purpose of this paper is to investigate the feasibility of irradiation sterilization of two ancient Chinese tomb chamber murals,the two Southern Tang dynasty cemeteries,and the Dahuting Han dynasty,using the E-beam method.To investigate the changes in the physical and chemical properties of common ancient pigments,adhesives,typical strains of burial chambers,and simulated burial chamber murals after E-beam irradiation.The main contents are:(1)The effects of eight natural mineral pigments and three common binders after E-beam irradiationAmong the eight natural mineral pigments,only two pigments(lead white and calcium carbonate)showed significant color changes after two energies of E-beam irradiation.The △E00 values of the two groups of lead white and two groups of calcium carbonate were 4.41,3.72,3.45,and 4.38 after irradiation of E-beam with energy 10 Me V,dose 5 k Gy.The color changes of these two pigments at different doses showed that the degree of the color change of lead white and calcium carbonate after irradiation was related to the irradiation dose and the placement time after irradiation.The results of various tests on the two pigments before and after irradiation showed that the chemical structure of the pigments did not change significantly after irradiation,and the color changes of lead white and calcium carbonate after electron beam irradiation were mainly attributed to the newly appeared paramagnetic color centers within the pigments after irradiation.By comparing the changes in the internal amino acid composition ratios of the three common binders before and after irradiation,it was concluded that the internal amino acid composition ratios of gelatin deviated from its original animal glue range after electron beam irradiation at sterilization doses.No significant changes were observed after irradiation of egg whites and yolks.(2)The effects of typical strains in tombs and simulated murals after electron beam irradiationAccording to the actual colony structure in the two Southern Tang dynasty cemeteries and the Dahuting Han dynasty,the typical fungal representative Penicillium and bacterial representative Aeromonas were selected for irradiation sterilization experiments.The results showed that the electron beam irradiation dose of 6 k Gy could completely inhibit the activity of the two strains with no new growth signs for 1 month.The survival of the two strains after irradiation was related to the type of strain,irradiation dose,and the culture days of the strains before irradiation.The irradiation tolerance of Penicillium was stronger than that of Aeromonas.In the E-beam irradiation experiments conducted on the simulated murals,the pigment layers and the ground war layer did not show significant and regular color changes at a dose of 80 kGy.Elimination experiments were designed and simulated to run for ozone generated during E-beam operation.The ozone concentration at the end of the elimination device was 0.023 ppm,which was following the national standard.Combining with the effectiveness of sterilization on typical strains and the indestructibility of simulated murals,the application of E-beam irradiation to the sterilization of tomb murals is deemed feasible.