Irradiation Effects Of Electrons And Protons On Lense Of K208 Glass Substrate Coated With Antireflective Films

In this thesis, the method for space charged particles ground simulation test was studied by means of experiment results and Monte Carlo simulation method for an optical lens, which has the substrate of K208 glass and is coated with the anti reflect reflective films of MgF2, ZrO2 and Al2O3. The range and energy loss distribution of the protons and electrons in the optical lens were analyzed in detail using SRIM and CASINO programs. The simulation results show that most amount of the energy of proton with 0.01-0.16MeV was absorbed by the surface film of the lens, while the majority of the energy of the protons with energy greater than 0.16 MeV is dissipated in substrates. For the electrons with energy of 0.01 - 1MeV, the energy dissipation takes place both in surface film and substrates, while the larger energy results less effect on surface film. Synergistic effect is found during the combined irradiation of proton and electron on the lens, i.e. the change in spectra due to the complex irradiation of proton and electron is not simply equal to summation of the single irradiation of each species under the same energy and fluence. Combining the orbital energy spectrum and considering the dose effect of irradiation damage for lens, a recommendation that using 0.01-1MeV spectrum to simulate the real orbital energy spectrum is proposed. Based on the characteristics of the orbit energy spectrum to be simulated, it should divide the energy spectrum into several ranges and chose a proper energy within each energy section to perform the irradiation test in sequence of the selected energy. It is better to use proton and electron simultaneous irradiation. As an example, a practice criterion for simulating geosynchronous orbit test is given.Using a space integrated irradiation simulation equipment and a high-energy proton accelerator, the rule of the variation in spectral transmittance was summarized for K208 glass base coated optical lens after proton and/or electron irradiation with different energy under the single, comprehensive and sequential irradiation mode. The transmittance is changed within the ultraviolet band after irradiated by charged particle. The variation in transmittance is increased and moved to the longer wavelength band with increasing radiation dose. The variation in spectral performance for lens shows a dose effect, i.e. the greater in irradiation dose results in more decrease in spectral variation. Electron irradiation induces a strong charging and discharging effect on the lens, which becomes more serious with the increasing the energy and dose of electron.It is found that the transmittance drops obviously after the irradiation by charged particles and a wide absorption band appears. The analysis of absorption band shows that characteristic peaks appear at 370nm, 400nm, 450nm, 490nm and 650nm, which can be attributed to the absorption of the F2 color centers in MgF2 film, the F2+ color centers in Al2O3 film, the F+ color centers in ZrO2 film and the non-bridging oxygen hole center (NBOHC) in the substrates, respectively. The absorption of the films is much stronger than that of the substrate, implying that the irradiation mainly cause the coloration of the antireflective films.