The Role of Proton Component in the Evolution of K-208 Glass Morphologyunder Combined Electron-Proton Irradiation
By the methods of atomic force microscopy (AFM) we investigated the surfaces of samples of K-208 glass after separate and combined irradiation in vacuum p<sub>v</sub> = 10<sup>−4</sup> Pa with protons and electrons with energies of 20 keV and 30 keV, respectively. At proton flux densities φ<sub>p</sub> and electrons φ<sub>e</sub> from 1 × 10<sup>11</sup> to 5 × 10<sup>12</sup> cm<sup>–2</sup> s<sup>–1</sup>, the fluences of the particles Φ<sub>p</sub> and Φ<sub>e</sub> varied in the range 1 × 10<sup>14</sup> –5 × 10<sup>16</sup> cm<sup>–2</sup>. The obtained results allow us to state the following: the character of changes in the morphology of the samples under the action of protons and electron-proton plasma for φ<sub>p</sub> <5 × 10<sup>12</sup> cm<sup>–2</sup> s<sup>–1</sup> at φ<sub>e</sub>: φ<sub>p</sub> < 3 coincides and is due to radiation-stimulated stresses, reorganization of the glass grid and formation of gas-filled bubbles; at φ<sub>p</sub> ≥ 5 × 10<sup>12</sup> cm<sup>–2</sup> s<sup>–1</sup>, the change in the morphology of the glass is determined by the mass transfer caused by the local heating of the near-surface layer. In the case of proton irradiation, a model is proposed that describes the process of field migration of sodium ions, which plays a key role in the restructuring of the microstructure of glass and the release of atoms of nonbridging oxygen.