Self-supporting thin Tin targets fabricated by ultra-high vacuum evaporation for heavy-ion induced reactions

Self-supporting thin films of 116,118Sn isotopes have been fabricated using ultra-high vacuum (UHV) facility at the Inter-University Accelerator Centre (IUAC), New Delhi. Owing to the requirements for fusion and quasi-elastic backscattering studies, several self-supporting thin target films with areal density ~ 250–600 μg/cm2 were fabricated. Attempts were also made to prepare thin films by cold rolling technique, and an areal density of ~ 1.8 mg/cm2 could be achieved after several rolling cycles. Various advanced characterization techniques viz., Rutherford Backscattering Spectrometry (RBS), Energy Dispersive X-ray Spectroscopy (EDS), Fourier Transform Infrared (FTIR) Spectroscopy and Field Emission Scanning Electron Microscopy (FE-SEM) were employed to (i) ascertain levels of trace- and heavy-impurities, if present, in the fabricated target films, (ii) determine exact thickness of the films, and (iii) study morphological changes, if any, in the films after irradiation with high energy ion beam fluence of ~1015 ions/cm2. The characterization results manifested that negligible amount of impurities was present in the films, and they were quite stable under energetic ion-beam irradiations. The fabricated films were successfully used as targets in online nuclear physics experiments to measure quasi-elastic backscattering cross-sections in 7Li induced reactions.