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

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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.