Effect of proton irradiation on transmittance of Al filter at EUV waveband

Part of low-earth orbit’s space radiation environment was simulated to investigate the influence on the transmittance change of the aluminum filter used on the space solar telescope in extreme-ultraviolet(EUV) waveband. The transmittance was measured before and after proton irradiation with energy of 100 keV and dose of 6×1011/mm2. And the microstructures of aluminum filter were investigated by transmission electron microscopy(TEM). The experimental results show that the transmittance of filter increases from 12.1% to 15.0% because of the thickness decrease of filter after proton irradiation, and the thickness of the filter beoames inhomogeneous, resulting in the optical performance degradation of the filter and sub-peak in the transmittance curve. The reason is tha