A major advance in neutrino detection has been made thanks to research by an international team of scientists led by Joshua Klein. In a mine in Sudbury, Ontario, approximately 240 km (about 149.13 mi) from the closest nuclear reactor, the international collaborative experiment Sudbury Neutrino Observation (SNO+) has discovered subatomic particles known as antineutrinos using pure water. According to Klein, previous studies have carried out this using a liquid scintillator, a medium that resembles oil and emits a great deal of light once charged particles such as electrons or protons travel through it. Given that the detector must be placed 240 kilometers, from the reactor, Klein notes that a lot of costly scintillators is required. Our research demonstrates that very big detectors could be constructed to perform this function using only water.
What are neutrinos and antineutrinos, and why are they important?
According to Klein, neutrinos and antineutrinos are minuscule subatomic particles that are the most prevalent in the universe and are thought to be the fundamental building blocks of matter. However, scientists have had trouble detecting them because of their sparse interactions with other particles and due to their inability to be protected, meaning they can pass through anything. However, this does not imply that they are dangerous or radioactive because nearly 100 trillion neutrinos travel through our bodies every second undetected. These characteristics, however, also make such elusive particles useful for understanding a variety of physical phenomena, such as the creation of the universe and the study of far-off astronomical objects, and they “have practical uses as they are able to monitor nuclear reactors and possibly detect the clandestine nuclear activities,” according to Klein.
Where they come from
According to Klein, although neutrinos are typically generated by high-energy reactions such as nuclear reactions in stars, such as the fusion of hydrogen into helium in the sun, where protons and other particles cross paths and release neutrinos as a byproduct, antineutrinos are typically generated artificially, “for example, in nuclear reactors that produce antineutrinos as a result of the radioactive beta decay of the reaction in order to fission atomic nuclei,” he says. “As a result, nuclear reactors produce a significant amount of antineutrinos, making them an ideal source for research.”
Why is this newest discovery significant?
Therefore, monitoring reactors by analyzing their antineutrinos enables us to determine whether they are on or off and, possibly, what type of nuclear fuel they are burning, according to Klein. According to Klein, this makes it possible to keep an eye on a reactor in another nation to determine whether it is shifting from producing electricity to producing material suitable for weapons. Making the evaluation with water alone means that an array of large but cheap reactors could be constructed to ensure that a country, for example, is adhering to its obligations in a nuclear weapons treaty; it is a handle on nuclear nonproliferation.
Why hasn’t this been done earlier
Since reactor antineutrinos have very low energies, a monitor needs to be completely free of radioactivity, according to Klein. Additionally, so that the events can be noticed, the detector must be able to “trigger” at a low enough threshold. According to him, it’s crucial that a reactor hold at least 1,000 tons of water when it’s 240 kilometers away. SNO+ met each of these requirements.
Leading the charge
Logan Lebanowski and Tanner Kaptanglu, two of Klein’s former students, are credited with leading this initiative. The initiative was overseen by Lebanowski, a former postdoctoral researcher, even though Kaptanglu’s doctoral thesis included the idea for this evaluation. “With the help of our instrumentation group here, we designed and built all the data acquisition electronics and developed the detector ‘trigger’ system, which allowed SNO+ to have an energy threshold low enough to detect the reactor antineutrinos.”