Antineutrinos detected using water

Source: By The Indian Express

In a lab buried around 2000 kilometres under the ground in Canada, scientists accidentally discovered antineutrinos using extremely pure water for the first time.

Antineutrinos are the antimatter of neutrinos. They have an almost non-existent mass and charge and they rarely if ever interact with other particles. This makes them especially difficult to detect. They are produced as a byproduct when neutrons separate into protons and electrons in nuclear reactors.

The Sudbury Neutrino Observatory (SNO) was being upgraded to make it SNO+ when the discovery was made. The scientists detected the antineutrino even before the observatory’s upgrades were completed.

As the observatory’s detector’s components were being upgraded in 2018, the observatory was filled with ultrapure water, and the detector was being calibrated. While looking through the calibration data, the researchers picked up signals of an antineutrino that came from a nuclear power station hundreds of kilometres away.

It intrigues us that pure water can be used to measure antineutrinos from reactors and at such large distances. We spent significant effort to extract a handful of signals from 190 days of data, Lebanowski said. The result is gratifying,” said SNO+ collaborator Logan Lebanowski in a press statement.

Usually, in order to detect antineutrinos, “liquid scintillators” scientists need to use a method called liquid scintillation. Typically, this involves the use of chemicals like linear alkybenzene.

But this new discovery suggests that it would be possible to build neutrino detectors using ultrapure water, which is non-toxic, relatively inexpensive and easy to handle. This could mean that detectors such as SNO+ could be used to monitor the power output of a nuclear plant from a distance.

The results of the research were published in the peer-reviewed journal Physical Review Letters last month.