以北祁连锆英石(776Ma±10Ma)为研究对象,利用^60Co源γ射线辐照装置对其进行γ射线辐照。借助偏反多功能显微镜、阴极发光、背散射电子、电子探针对样品微观形貌进行观察与分析,并对样品产出的地质背景和化学成分进行研究,并利用X射线衍射、激光拉曼光谱和红外光谱等表征手段对γ射线辐照前后样品的物相、结构进行测试分析。并对样品产出的地质背景和化学成分进行研究,明确放射性核素固化介质备选矿物锆英石的特征结构变化及抗γ射线辐照能力。结果表明:北祁连所产出的锆英石系变质成因,经约7.76×10^8 a的地质演变后,对UO2和ThO2的包容量仍为0.118%,晶胞参数较标准样品发生了10^-3 nm量级的微小变化。样品经576kGy的γ射线辐照后晶胞参数较辐照前发生了10^-4 nm量级的变化,辐照后样品结构的无序程度略显增强。锆英石在包容一定量U和Th的情况下具有较好的抗γ射线辐照结构稳定性。
In order to investigate the structural evolvement and the capability of resistance toγ-ray irradiation for zircon as mothball waste forms of radionuclide,the zircon crystals(776Ma±10Ma)were studied as investigative object collected from the North Qilian region.All the samples were irradiated by using a ^60Coγ-ray source with 576 kGy doses.Microstructures of the as-gained samples before and afterγ-ray irradiation were characterized by means of a multi-functional microscope,cathodoluminescence(CL),backscattered electron microprobe(BEM).The phase and structure of the sample was analyzed by X-ray diffraction(XRD),Raman spectroscopy(Raman),infrared spectroscopy(IR)and scanning electron microscopy(SEM).Meanwhile,the geological backgrounds and chemical compositions of zircons originating from natural rocks were analyzed.The results indicated that the as-gained crystals resulted from metamorphism which undergone7.76 million years geological evolvement and still contained UO2 and ThO2 with the contents of0.118%.There was alteration of 10^-3 nm magnitude in the crystal cell parameters measured when compared with the standard XRD card of zircon.The irradiation on the crystalline samples byγ-ray induced to the alteration of 10^-4 nm magnitude for their crystal cell parameters.It was showed that zircon crystals with a certain amount of UO2 and ThO2had better structural stability for theγ-ray irradiation.