Effect of Optical Radiation on the Properties of Gamma Radiated Silicate Glass

Effect of Optical Radiation on the Properties of Gamma Radiated Silicate Glass

R. T. Khaydarov, H. B. Beisinbaeva, and R. R. Khaydarov

Fused silica, an amorphous form of silicon dioxide is an optical material extensively used for laser applications in, e.g., inertial confinement fusion (ICF) programs, due to its excellent ultraviolettransparency, optical homogeneity, and high antidamage performance in UV pulse laser.For its practical applications, the critical issue in the defect formation and densification, which can occur under different experimental conditions, including photon [1], electron [2] and ion [3] irradiation and different shock compressions [4].However, in ICF applications the main sources for the silicate damage are the neutrons and gamma radiation produced by deuterium–tritium fusion reactions.Such preexisting defects may result in furtherlaser-induced damageof silica during laser applications. Therefore, understanding the nature of light absorption andfluorescence of point defects becomes important factor for controlling the evolution of laser-induced damageand designing an effective damage mitigation procedure inlaser applications [5].In particular, elucidating the effect of neutron and gamma radiation on the properties of such optical materials is crucial for constructing highly specialized window materials for transmission lines in plasma heating and diagnostic systems innuclear fusion reactors [6-10].

In this work, using the mass-spectrometric method, we study the effect of intense laser radiation on the surface of silicate glass prior irradiated by gamma radiation. We also study the effect of metallic inclusions on the absorption properties and light resistance of silicate glasses.Experimental results show that the gamma radiation with dose 5 × 104 R leads to the degradation of the surface resistance of this optical dielectric to electromagnetic radiation. Depending on the dose of the radiation the laser radiation can result in either surface erosion or its pronounced cracking. We also found that the efficiency of the degradation process is determined not only by the radiation dose, but also by the presence of different impurities in the glass.For example, different metallic inclusions (Fe or Ce) further decrease the resistance of the glasses as these inclusions become centers of intense light absorption.

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