重离子和γ辐照硼硅酸盐玻璃的辐照效应对比

Comparison of Irradiation Effect on Borosilicate Glass Irradiated with Heavy Ion and Gamma Ray

为研究玻璃固化体在不同辐照方式下的宏观和微观结果及其对应关系,使用重离子和γ辐照硼硅酸盐玻璃,分别测量了辐照后硼硅酸盐玻璃的硬度和模量变化。发现在γ辐照条件下,直到吸收剂量达到6×10~6 Gy,硼硅酸盐玻璃的宏观性质(硬度和模量)均未发生明显改变。在Xe离子辐照条件下,当辐照剂量达到0.1 dpa时,硬度和模量减少达饱和值。此外,测量了γ辐照后的硼硅酸盐玻璃的吸收光谱,得到了辐照后硼硅酸盐玻璃带隙随吸收剂量的变化规律,讨论了辐照产生的微观缺陷来源和产生机理。发现重离子辐照产生的硬度和模量的下降主要来源于玻璃网络结构的断裂,而重离子的核能量沉积是造成网络体结构断裂的主要原因。结合γ辐照样品的吸收光谱结果,通过对比γ射线和重离子辐照后的样品硬度和模量变化不同趋势可发现:γ辐照会在硼硅酸盐玻璃中产生微观缺陷(非桥氧空位色心等),这些缺陷主要来源于网络体末端与钠相连的键的断裂。而网络体末端的断裂不影响硼硅酸盐玻璃的网络体结构,所以γ辐照产生的缺陷不会引起硼硅酸盐玻璃的硬度和模量变化。

To study the macroscopic and microscopic properties and their corresponding relation of high level waste glass after different irradiation methods,borosilicate glass was irradiated with gamma ray and heavy ion.The hardness and modulus of borosilicate glass irradiated with Xe ion and gamma ray were measured.For irradiation of gamma ray,there is no obvious change in hardness and modulus of borosilicate glass until the absorption dose up to 6×10^6 Gy.For irradiation of Xe ion,the hardness and modulus of borosilicate glass drop to the saturated values with irradiation dose of 0.1 dpa.Absorption spectra of gamma ray irradiated borosilicate glass were measured.The trend that band gap of borosilicate glass evolved with the absorption dose was obtained.The origin and possible formation mechanism of micro defects in borosilicate glass induced by irradiation of gamma ray were discussed.It can be obtained that the decreases in hardness and modulus of borosilicate glass irradiated with heavy ion are attributed to the breakdown of glass network.Furthermore,the breakdown is mainly induced by the nuclear energy deposition.Comparison of different trends in hardness and modulus of glass irradiated with heavy ion and gamma ray suggests that micro defects in glass could be produced by irradiation of gamma ray.The micro defect of non-bridging oxygen hole center is mainly formed from the breaking of the end of network.The end of network in glass is connected to sodium.The breakdown of end of network in glass might have no influence on network of glass.Thus,influence on hardness and modulus of borosilicate glass will not be induced by the micro defect with irradiation of gamma ray.