GRETINA and Its Early Science

Abstract

γ-Ray spectroscopy continues to be an important tool for the study of nuclei. Excitation energies can be measured directly and in model-independent ways, and thus are among the key observables that can guide our understanding of atomic nuclei. With the availability of short-lived rare-isotope beams, the development of position sensitivity of γ-ray detection systems has been crucial in combating the Doppler broadening encountered for the energies of γ-rays emitted in flight, which are necessary to obtain good energy resolution while maintaining high efficiency. The advanced γ-ray tracking array GRETINA began its science mission at the National Superconducting Cyclotron Laboratory (NSCL), where rare-isotope beams are produced at velocities exceeding 30% of the speed of light. With selected examples from nuclear structure physics and nuclear astrophysics, we show the breadth and reach of the science program afforded by GRETINA and provide an outlook for what can be accomplished with the full 4π array GRETA at the Facility for Rare Isotope Beams (FRIB).