Production and Characterization of Bismuth Targets

Targets are an important part of nuclear physics. In heavy element research, targets are a source of nucleons and set the location for the reaction to happen. For our reactions of interest, the target provides nucleons that the beam can interact with to produce the desired heavy element. This summer, our group worked to make bismuth targets via physical vapor deposition for use in the cyclotron for heavy element research. In particular, these evaporated targets will be compared to the novel bismuth incorporated graphene targets our group is currently investigating for their possible higher sustainability against beams. After commissioning new components to our thermal evaporator, we evaporated 500 μg/cm² Bi onto a carbon substrate through resistive heating. After finalizing the data and sensor used to measure the thickness of the bismuth, we were able to start the production of carbon backed bismuth targets to be used in the cyclotron. After finalizing our targets, we will take them up to LBNL to test out in their cyclotron. The reaction we are hoping for is ²⁰⁹Bi + ⁴⁸Ca → ²⁵⁴Lr + 3n⁰.