质子辐照铝膜反射镜的慢正电子湮没研究

Slow positron annihilation study of Al film reflector after proton irradiation

采用分光光度计测定了60keV质子辐照后铝膜反射镜反射光谱的变化规律.用慢正电子湮没等分析技术研究了辐照损伤的微观机制.结果表明,当质子辐照主要作用于反射镜铝膜层中时反射镜在200—800nm波长范围内反射率随辐照剂量增加而下降.入射质子可对铝膜中的缺陷产生填充作用,减小铝膜中电子密度,增加弱束缚电子带间跃迁.紫外至可见光能量较高的波段可引起带间激发跃迁,使相应的谱段反射率下降,导致反射镜光学性能的退化.

The spectral reflectance is measured after 60 keV proton irradiation by the spectrophotometer. The microscopic mechanism of irradiation damage of Al film reflector is studied by the slow positron annihilation technique and X-ray diffraction. The results show that the spectral reflectance of Al film reflectors decreases in the wavelength range of 200-800nm with increasing proton irradiation fluence and the radiation damage is mainly concentrated on the Al film of the reflector. The implanted protons may fill the dcfccts in Al film layer, thus decreases the electron density of Al film and enhances the interband transition of loose bound electrons. The interband transition can be excited by electromagnetic waves ranging from UV to visible and the spectral reflectance decreases in the corresponding wave band, which eventually results of the degradation of optical property of the reflector.