Fabrication and characterization of thin 116Cd target films for fusion measurements

Abstract

Fabrication and characterization of thin target films of 116Cd by physical vapour deposition technique are reported. The target films were used in the study of nuclear fusion dynamics near the Coulomb barrier with a beam of 16O. Because of the low melting point of cadmium and its re-evaporation after deposition, coupled with availability of a very small quantity of isotopically enriched material, an unconventional method was employed to fabricate the targets. The prepared target films were characterized using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), X-ray Diffractometry (XRD) and Rutherford Back-scattering Spectroscopy (RBS) to obtain their surface morphology, elemental composition, chemical composition and thickness, respectively. Thickness of the enriched target films were in the range of 20 –50 μg/cm2. Isotopic composition of one of the target films was ascertained in an in-beam experiment using a recoil mass spectrometer. It was observed that abundance of 116Cd in the fabricated target film was significantly lower than the value quoted by the supplier of the source material.