A dataset of 532nm high reflectivity coating with reduced resistance to laser damage caused by nodule defects after exposure to gamma rays

Fused silica and S-BSL7 glass with 532 nm high reflectivity (HR) coatings were irradiated using 60Co gamma-ray source at a dose rate of 1 Gy/s for a total dose of 1–500 kGy. After irradiation, the samples were subjected to raster scan testing using a laser with a pulse width of approximately 8.6 nanosecond and wavelength of 532 nm to measure their laser-induced damage threshold (LIDT).The results showed that S-BSL7 glass was significantly darkened after gamma-ray irradiation, whereas fused silica did not change color, but E’ color centers appeared at a dose of 500 kGy. All the coated samples maintained a high level of reflectivity. No significant changes are observed in the material structures of the samples. However, the LIDT of the high reflectivity film decreased significantly after 500 kGy irradiation, whereas the LIDT of all other samples showed no obvious degradation. Scanning electron microscopy of the damage pit cross-sections revealed that all the damage was initiated by nodular defects, suggesting that gamma rays affected the nodular structure.The Monte Carlo simulations were used to compare the energy deposition and electron excitation conditions of the film with a nodular structure and an intact multilayer structure under gamma-ray irradiation. We found that the nodular structure slightly enhanced the effect of gamma rays on the film. Considering the small size of the nodules, this small enhancement was only apparent under high-dose gamma-ray irradiation.