Speaker
Description
Neutron capture provides a low-energy but distinctive delayed signal that can be exploited in large-volume neutrino telescopes. At TeV–PeV energies, hadronic interactions in neutrino-induced showers produce secondary neutrons. The subsequent neutron capture signals ("neutron echo") offer a powerful tool to distinguish hadronic and electromagnetic components, enabling the separation of charged-current and neutral-current interactions and providing sensitivity to neutrino flavor composition.
Extending to lower energies, neutron capture also enables event-level detection of MeV-scale antineutrinos, such as those from the long-awaited next Galactic core-collapse supernova (CCSN). In inverse beta decay, a prompt positron is followed by a delayed neutron signal, forming a characteristic coincidence signature. In seawater, capture on naturally abundant chlorine enhances this signal through higher-energy gamma emission and shorter capture times, significantly improving detection efficiency and background rejection. In addition to simulations, we validate this approach experimentally using an AmBe neutron source with a single hDOM of TRIDENT, achieving a statistically significant neutron signal despite its lower intensity compared to that expected from a typical Galactic CCSN.
