This award will support Professors Sperry Darden and Sudhir Sen of Notre Dame University in collaboration with researchers Ghirardo Murillo, Marco Fernandez, Jesus Ramirez and Olga Avila of the Mexican National Institute for Nuclear Research (ININ). The purpose of the research is to study the elastic scattering of protons using the tandem accelerators available at Notre Dame and ININ. Measurements of elastic scattering will allow the determination of various energy-characterizing parameters and also help to gauge the success of model calculations that describe in detail nuclear structure. Preliminary tests reveal the existence of interesting structures in the data. The investigators intend to explore these structures by refining their experimental frame work, using smaller energy steps, increasing the number of angular measures, and measuring at energy levels not tried before. Measurements utilizing a polarized proton beam will be carried out at the University of Notre Dame, and exploratory cross-section excitation function measurements, as well as some cross-section measurements, will be carried out at the Mexican Nuclear Center.