An international team of scientists, including Joshua Klein, has achieved a remarkable scientific breakthrough in detecting neutrinos. The Sudbury Neutrino Observation (SNO+) experiment located in a mine in Sudbury, Ontario, utilized pure water to detect low energy antineutrinos from nuclear reactors for the first time. This achievement can pave the way for a more straightforward and inexpensive method to detect nuclear activities.
Significance of the Breakthrough
Prior experiments had detected neutrinos using liquid scintillator, an expensive medium. The SNO+ detector satisfies all the criteria for detecting reactor antineutrinos using water. Furthermore, antineutrinos produced by nuclear reactors are an ideal source for studying them and can be used to monitor nuclear reactors and detect nuclear activities. A reactor’s monitoring could indicate if it is producing weapons-grade material using antineutrinos. However, it is challenging to detect reactor antineutrinos because they are low-energy particles, and a detector must be very clean from radioactivity. The SNO+ team overcame that obstacle as their detector achieved all the conditions needed to detect reactor antineutrinos using water.
Implication of Findings
The success of this experiment has significant implications for the development of techniques used to monitor nuclear reactors. Antineutrino detection thresholds could be lowered by using safe and inexpensive materials such as pure water. These findings can be used to boost efforts towards better monitoring of nuclear activities worldwide.
Details about SNO+ Experiment
The Sudbury Neutrino Observatory (SNO) had discovered neutrino oscillation led to the Nobel Prize for Physics in 2015. In contrast, SNO+ is an advanced version of SNO, specifically upgraded to detect antineutrinos from distant nuclear reactors. Ultrapure heavy water was used to detect energetic neutrinos from the sun in SNO. The new detector was fitted with a nitrogen cover gas system to significantly lower background rates. The low energy detection threshold with good efficiency enabled scientists to observe antineutrinos interacting in pure water. A dozen or so events were identified that could be attributed to interactions from antineutrinos in pure water, and the statistical significance of the antineutrino detection was 3.5σ, which is below the threshold of a discovery in particle physics.
Neutrino Detection at LHC
In other breakthrough research, FASER and SND@LHC achieved the first observation of collider neutrinos at this year’s electroweak session of the Rencontres de Moriond, including muon neutrinos and candidate events of electron neutrinos. Neutrino experiments have only previously studied neutrinos coming from space, Earth, nuclear reactors, or fixed-target experiments. FASER and SND@LHC will cover a much higher energy range between a few hundred GeV and several TeV, contributing to the study of high-energy neutrinos from astrophysical sources. Moreover, these experiments can test the universality of their interaction mechanism by measuring the ratio of different neutrino species’ production rates produced by the same type of parent particle.
The detection of subatomic particles using pure water at SNO+ and collider neutrinos by FASER and SND@LHC could pave the way for exploring new physics scenarios. These discoveries would contribute significantly to our understanding of particle physics while holding immense promise for future scientific research in nuclear physics.
Image Source: Wikimedia Commons
