Free volume in a thin film of epoxy resine coated on a metal base studied by positron annihilation

用正电子湮没方法可以研究镀在金属基板上的薄膜的自由体积。然而，为了研究聚合物的表面，需要一种脉冲慢正电子束（PSPB）来确定在所研究的聚合物中的注入时间。在这个项目中，一个小仪器桌面大小，以产生一个PSPB使用放射性同位素（RI）已被使用。采用射频方法，在直径为2cm、长为5cm的铝管上施加射频场，获得了脉冲聚束光束。长度由正电子通过电子管的飞行时间决定。因此，40 MHz RF用于将rundum波束聚束成聚束波束。脉冲束宽为500 ~ 600 ps，可用于研究寿命大于1.5ns ~ 2ns的聚合物样品。该装置已成功地应用于聚乙烯、环氧树脂、环氧复合材料、硅基环氧涂层等聚合物样品的寿命测量。制备了碳离子注入超高分子量聚乙烯材料，研究了离子注入对材料表面的影响。表面变形，寿命变得比balk样品稍长。Ps形成强度在沉积位置的深度附近变小，其中碳注入层是预期的。得到了环氧树脂表面和体相的热膨胀系数，在聚乙烯中，随着深度的增加，电子偶素的生成量增加。用非破坏性方法观察了复合材料的表层。对广泛应用于集成电路和电子工业的硅基低K薄膜进行了研究，成功地观察到了正电子寿命约为50 ns的大空穴

Free volumes in a thin film coated on a metal base plate can be studied by positron annihilation. However, In order to study the surface of polymers, a pulsed slow positron beam (PSPB) is necessary to determine the injection time in the investigated polymer. In this project, a small apparatus desk-top size to generate a PSPB using radio isotopes (RI) has been used. The bunched and pulsing beam was obtained by the RF method, in which RF field is applied on an Al tube with 2cm diameter and 5cm length. The length is determined by the flight time of positrons through the tube. Thus 40 MHz RF is used to bunch the rundum beam to a bunched beam. The width is 500 to 600ps, which is enough to study polymer samples, which have lifetimes longer than 1.5ns to 2 ns.The apparatus to inject a pulsed and bunched beam in samples has been successfully applied to measure lifetimes of polymers : polyethylene, epoxy resin, epoxy composite, epoxy coated films on a Silicon metal. Carbon-implanted ultra-high molecular-weight polyethylene, was prepared and the surface affected by the ions was studied. The surface was distorted and the lifetime became a little longer than the balk sample. Ps formation intensity became small around the depth of the deposited position, where the carbon implanted layer is expected. The heat expansion coefficient of the surface and the bulk of epoxy resin was obtained.The increase in the positronium formation with increasing the depth was observed in polyethylene. The skin layer of the composite materials was observed by a non destructive method. Low K films on Silicon plate, which are extensively used in IC and electric industry has been studied.Large holes with about 50 ns positron lifetime has been successfully observed