Analysis and characterization of bismuth incorporated graphene targets

One method of producing heavy exotic nuclei that lie far from the β-line of stability requires a reaction between a target and a beam. For heavy element reactions, the target is typically a thin film made from a heavy isotope, while the beam will be made using a lighter isotope. Bombarding thin films with ion beams leads to target damage and degradation so having them made of robust materials is very beneficial. For this reason, investigating targets made of bismuth nanoparticles suspended in a graphene matrix for the production of heavy elements is of interest. Graphene allows for good structural integrity and has a high melting point, increasing its ability to withstand high beam intensities used to produce heavy and unstable exotic nuclei in low cross-section reactions. Two of these graphene incorporate bismuth thin film targets have been analyzed using confocal scanning microscopy to check for surface morphology, uniformity, and anything abnormal. Interestingly, large bismuth particles can be found semi-regularly throughout the target, and these large pieces have been found to have enormous heights ranging from 25 μm to over 50 μm in width and 20 μm in height, well beyond the manufacturer's specified nanoparticle sizes. Other characterization techniques used were X-ray diffraction to verify chemical composition and alpha particle energy loss to confirm target thickness. To test these targets in beam, we plan to run the fusion evaporation reaction ²⁰⁹Bi(⁴⁸Ca, 3n⁰)²⁵⁴Lr.