Abstract: The Gamma-Ray Energy Tracking Array (GRETA) is a 4pi detector designed to study a broad science program in nuclear structure over a wide range of beam energies and velocities from Coulomb barrier to 100’s MeV/A. It combines highly segmented HPGe crystals with advanced digital electronics and signal processing to identify individual gamma-ray interaction points within the crystals to simultaneously achieve high energy resolution, high efficiency and good background rejection (peak-to-total).
The GRETA Project started in 2017, following nearly a decade of successful science with the predecessor GRETINA array, and completed construction and initial commissioning of all technical systems (mechanical, electronics and computing) with a subset of Quad Detector modules at the Department of Energy’s Lawrence Berkeley National Laboratory in the summer of 2025. It is currently being installed at the Facility for Rare Isotope Beams (FRIB), with first science measurements expected in early 2027. I will review the GRETA project, both science and technical as well as performance, and the progression toward anticipated first science at FRIB.