Radiation Defects Induced by Proton Exposure in Hollow Zinc-Oxide Particles
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ion Defects Induced by Proton Exposure in Hollow Zinc-Oxide Particles A. N. Dudina, *, V. V. Neshchimenkoa, **, and V. Yu. Yurinaa aАmur
State University, Blagoveshchensk, 675000 Russia *e-mail: [email protected] **e-mail: [email protected]
Received December 4, 2019; revised January 6, 2020; accepted January 8, 2020
Abstract—Zinc-oxide powders consisting of spherical hollow particles are obtained by hydrothermal synthesis. Comparative analysis of the diffuse reflectance spectra and their changes after irradiation with 100-keV protons of powders of micrometer-sized hollow and bulk particles of zinc oxide is carried out. We present the results of the physical and mathematical simulation of the interaction of a low-energy proton beam with zincoxide particles, using the GEANT4 software package. The calculation results and the experimental data are compared. Hollow particles have a greater radiation resistance to protons compared to micrometer-sized bulk particles. The effect is determined by the absence of radiation-induced defects in the volume of spherical particles, a large ionization loss associated with surface-defect formation, and the significant relaxation of radiation-induced defects in a thin layer of spheres. Keywords: zinc oxide, hollow particles, optical properties, irradiation, defects, surface morphology, specific surface of hollow particles, simulation, GEANT4 DOI: 10.1134/S1027451020040242
INTRODUCTION Zinc-oxide-based powders have unique electrical and optical properties; therefore, they are used as pigments for the thermostatic coatings of spacecraft [1, 2]. These properties are associated with a large band gap, a stable structure that ensures relatively high photo and radiation resistance compared to other pigments (for example, TiO2, Zn2TiO4, Al2O3). Like other pigments, zinc-oxide powders are exposed to various types of cosmic radiation. Various defects of the crystal lattice, arising during irradiation, decrease the reflectivity and increase the integrated absorption coefficient. Determination of the types of induced radiation defects and their concentrations for various configurations of zinc-oxide particles is an urgent task related to thermostatic coatings. The problem of creating new “solar reflector” thermostatic coatings and improving their optical and radiation properties has been solved since the beginning of the development of space research. In the 1970s, the main contribution was made by American scientists, first of all, L.V. Fogdall, I.E. Gilligan, S.S. Cannaday, M. McCargo, S.A. Greenberg, N.J. Douglas, R.R. Brown, R.L. Kroes, and J.C. Arvesen. In Russia, the degradation of the thermostatic coatings of spacecraft was investigated by E.A. Barbashov and V.A. Bagatov from the All-Union Institute of Aviation Materials and employees of several laboratories: the laboratory led by Professor
Akishin at the Research Institute of Nuclear Physics, Moscow State University (V.I. Titov, G.G. Soloviev, S.K. Guzhova, and L.S. Novikov); the laboratory led by Professor Mikhailov at the Researc
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