Led by Lawrence Berkeley National Laboratory (LLNL), the Gamma-Ray Energy Tracking Array (GRETA) is on track to be the world’s most powerful gamma-ray reading instrument. Construction of GRETA was completed at LLNL, and GRETA is now prepared for user operation at FRIB.

Science it will enable

GRETA is a novel instrument for studying the properties of atomic nuclei through the precise measurement of γ rays that reveal the energies of properties of excited quantum states of nuclei. Optimized to reconstruct the energy and 3D position of γ-ray interactions within the germanium crystals, GRETA’s design innovates through the combination of full solid-angle coverage with high detection efficiency, excellent energy and position resolution, and background rejection capability through γ-ray tracking, to majorly contribute to a large fraction of the nuclear structure and nuclear astrophysics programs at FRIB. 

GRETA will provide new insights into the nature of the nuclear force and will help decipher how the properties of rare isotopes connect to the fingerprints of element and isotope production in the universe.

Set to become the flagship detector at FRIB, GRETA is expected to be 10 to 100 times more sensitive than previous systems, enabling scientists to trace gamma-ray emissions from rare isotopes with unprecedented precision.  

Collaborations

Lawrence Berkeley National Laboratory led the GRETA project. Argonne National Laboratory, Michigan State University, and Oak Ridge National Laboratory contributed to its timing and trigger electronics, the detector characterizations, and γ-ray tracking, respectively.