高能氩离子在聚苯乙烯中的电子能损效应研究

Electronic Energy Loss Effects in Polystyrene Irradiated with High Energy Argon Ions

用１．４ＧｅＶ氢离子对多层堆叠的厚约５３ｍ的聚苯乙烯薄膜在室温和真空条件下进行了辐照；对辐照后的样品进行了从红外到紫外的光吸收测量．测量结果显示，材料经高能红离子辐照后发生化学降解，降解过程强烈依赖于电子能损；在能量沉积密度很高的径迹芯中，分子主链和苯环均遭到破坏；在电子能损高于 ０． ７７ｋｅＶ／ｎｍ时有炔基产生．

Stacked polystyrene films of about 53m in thickness were irradiated with 1. 4GeV argon ions at room temperature and in vacuum. The radiation induced Chemical changes of each film were studied by the Fourier-transform infrared (FT-IR) and ultraviolet/visible (UV/VIS) spectroscopies. It is found that the material is seriously degraded after irradiation and the chemical modifications depend strongly on electronic energy loss. Significant degradation of the material occurs above about 0. 77keV/nm at the dose of 5. 5 X 1012 ions/cm2 corresponding to an energy deposition of 6. 4MGy. The main chains of PS as well as the phenyl ring are destroyed in the track core simultaneously. Damage cross sections Of alert 29urn2 are found for phenyl ring and the -CH2- group. Aldynes are produced above an energy loss of 0. 77keV/nm .