Scientists Detect Reactor Antineutrinos with Novel Detector
First Observation of Coherent Elastic Neutrino-Nucleus Scattering from Nuclear Power Source
Researchers have successfully detected elusive antineutrinos emanating from a nuclear reactor using a compact, 3-kilogram detector. This significant achievement marks the first observation of Coherent Elastic Neutrino-Nucleus Scattering (CEvNS) from a reactor source, providing new insights into fundamental physics.
Unveiling a Rare Particle Interaction
The CONUS+ experiment, situated just over 20 meters from the Leibstadt nuclear power plant in Switzerland, employed three 1-kilogram germanium semiconductor detectors. These sensitive instruments were designed to identify CEvNS, a phenomenon where a low-energy antineutrino interacts with an entire atomic nucleus, rather than individual subatomic particles.
This interaction causes a tiny, observable recoil of the nucleus. Think of it like a ping-pong ball nudging a stationary car; the car’s slight movement is the detectable effect. In this case, antineutrinos from the reactor’s core caused minute recoils in the germanium nuclei within the CONUS+ detectors.
During a 119-day observation period between 2023 and 2024, the team recorded an excess of 395 signals, after meticulously accounting for background noise and interfering signals. The location of the experiment is bombarded by an immense flux of antineutrinos, exceeding ten trillion per square centimeter each second.
“This value is in very good agreement with theoretical calculations, within the measurement uncertainty,” stated the research team.
“We have thus successfully confirmed the sensitivity of the CONUS+ experiment and its ability to detect antineutrino scattering from atomic nuclei,” added Dr. Christian Buck, a lead author on the study.
Pushing the Boundaries of Neutrino Detection
Neutrinos are notoriously difficult to detect due to their weak interactions with matter, historically necessitating massive experimental setups. While the CEvNS effect was first theorized in 1974 and first observed at a particle accelerator in 2017, CONUS+ represents a breakthrough in detecting this interaction at the low energies produced by nuclear reactors.
The implications of this CEvNS measurement extend beyond fundamental physics. Dr. Buck highlighted the potential for developing smaller, portable neutrino detectors. Such devices could offer novel ways to monitor a reactor’s heat output or track specific isotope concentrations in real-time.
Moreover, the CONUS+ data contributes valuable empirical evidence for refining the Standard Model of particle physics. The researchers noted that their technique exhibits a reduced reliance on complex nuclear physics assumptions compared to other experimental methods, thereby enhancing its sensitivity to potential physics beyond the Standard Model.
“The techniques and methods used in CONUS+ have excellent potential for fundamental new discoveries,” concluded Professor Manfred Lindner, the project’s originator. “The groundbreaking CONUS+ results could therefore mark the starting point for a new field in neutrino research.”
To further enhance measurement precision, the CONUS+ experiment was upgraded with improved and larger detectors in the autumn of 2024.
