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GODDESS detection system

Project Details

Principal Investigator
Funding Source
Office of Science
GODDESS detection system

The GODDESS detection system enables a new generation of high-resolution radioactive-beam experiments to determine the nuclear structure of exotic nuclei that play a critical role in explosive astrophysical environments that affect the chemical evolution of the universe. The physics program includes experiments on neutron-rich nuclei to determine neutron-capture rates for the synthesis of heavy elements in the rapid neutron capture process in neutron-star mergers and core-collapse supernovae, and experiments to determine critical proton-capture rates that impact novae and x-ray bursts. GODDESS is designed to operate at the Facility for Rare Isotope Beams (FRIB), but is already operational in experiments with radioactive and stable beams at the National Superconducting Cyclotron Laboratory (NSCL) and the ATLAS Facility at Argonne National Laboratory.


GODDESS is a coupling of a high-resolution charged particle detector array with the next-generation gamma-ray tracking array GRETINA, the demonstrator array for GRETA. When GRETA is completed, GODDESS will be a quasi-4pi particle-gamma spectrometer at FRIB, with millimeter position resolution and semiconductor energy resolution for both charged particles and gamma rays. GODDESS simultaneously measures light ions (such as protons, deuterons, and alpha particles) and gamma rays that are emitted when beams of exotic nuclei bombard a target containing light nuclei, such as hydrogen or deuterium. The high-resolution measurement of the outgoing ions provides detailed information on the formation of single-particle states in these exotic nuclei. The high-precision tracking of gamma rays provides an order-of-magnitude improvement in energy resolution and provides crucial complementary information on the decay of these nuclei. 

GODDESS system figure

The charged-particle detector is a 720-channel silicon detector array, based on ORRUBA (Oak Ridge Rutgers University Barrel Array). The barrel of position-sensitive strip detectors is capped upstream and downstream by highly-segmented endcap detectors with graded strip pitch, optimized to the kinematics of reactions with radioactive beams. Silicon-detector telescopes (up to three layers) can be instrumented in for light-ion identification. In order to detect, identify and track beam-like reaction products, GODDESS includes a position-sensitive gridded fast ionization counter (capable of counting at up to 1 million particles per second), and can also be coupled to large recoil spectrometers such at the S800 at the NSCL/FRIB. 

Contact: Steve Pain (


Research Staff
Steven Pain Portrait