Investigation of Ion Tracks in Polymer Materials Induced by Swift Heavy Ion Irradiation

本研究计画的目的是探讨快速重离子辐照聚合物薄膜所引起的结构变化及离子径迹的形成。高能重离子穿过聚合物箔，通过形成所谓的离子径迹引起结构改变。这些狭窄的圆柱形损伤区域对于聚合物在粒子加速器和空间飞行器装置中的应用具有实际意义，当这些装置被加速器中的高能重离子或在太空中的长期任务中的银河宇宙射线击中时。此外，研究快重离子辐照下聚合物材料中的离子径迹对于理解辐照降解机理具有重要作用。离子诱导材料改性的研究已经有很多年了，但对离子诱导材料的降解机理，特别是脂肪族聚合物中离子径迹的形成仍缺乏完整的认识。为此目的，将制造具有所需分子量和厚度的不同脂肪族聚合物（聚氟乙烯（PVFl）和三氟氯乙烯（CTFE））的聚合物箔，用快速重离子辐照并表征。离子辐照条件的变化（例如，宽范围的离子质量，离子能量，注量和通量）将进行详细的机理研究。从材料的损伤行为推断了离子径迹的形成机理。将使用各种分析方法进行离子轨迹研究，包括基于同步加速器的小角X射线散射（SAXS），以准确确定离子轨迹的大小和形状。此外，光谱方法（FT-IR，UV-Vis和质谱）将有助于量化结构变化。将进行热重分析（TGA）、差示扫描量热法（DSC）、拉伸强度测试、电导率和介电常数分析，以研究热、机械和电行为。

The aim of this research project is the investigation of structural changes and formation of ion tracks in polymer foils induced by swift heavy ion irradiation. Energetic heavy ions passing through polymer foils cause structural modifications through the formation of so-called ion tracks. These narrow cylindrical damage regions are of practical relevance for applications of the polymers in devices for particle accelerators and space vehicles when these are being hit by highly energetic heavy ions in accelerators or from galactic cosmic rays on long-term missions in space. Moreover, the study of ion tracks in polymer materials induced by swift heavy ion irradiation plays an important role for understanding the mechanism of radiolytic degradation. Ion induced modification of materials has been studied for years, but there is still an incomplete understanding of the degradation mechanisms, particularly ion track formation in aliphatic polymers. For this purpose, polymer foils of different aliphatic polymers (polyvinylfluorid (PVFl) and chlorotrifluorethen (CTFE)) with desired molecular weight and thickness will be fabricated, irradiated with swift heavy ions, and characterised. Variation of the ion irradiation conditions (e.g. a wide range of ion masses, ion energies, fluences and fluxes) will be performed for a detailed mechanistic investigation. The mechanism of ion track formation is deduced from the damage behaviour of the materials. Ion track investigation will be performed using a variety of analytical methods, including synchrotron based small angle X-ray scattering (SAXS) for accurate determination of the ion track size and shape. Moreover, spectroscopic methods (FT-IR, UV-Vis and mass spectrometry) will facilitate to quantify the structural changes. Tehrmogravimetric analysis (TGA), deferential scanning calorimetry (DSC), tensile strength test, conductivity and dielectric constant analysis will be performed to study the thermal, mechanical and electrical behaviour.