The world’s largest neutrino detector, known as the Jiangmen Underground Neutrino Observatory (JUNO), has officially commenced data collection in Guangdong, China. This facility is pivotal in advancing our understanding of neutrinos, often referred to as “ghost particles” due to their elusive nature and minimal interaction with matter.
Neutrinos are neutral subatomic particles with an incredibly small mass, making them challenging to study. They pass through ordinary matter almost without notice, leading to extensive research efforts to capture and analyze them. The significance of JUNO lies not only in its size but also in its capability to explore fundamental questions in particle physics, including the mystery of neutrino mass, which does not align with predictions from the Standard Model of Particle Physics.
JUNO is located approximately 700 meters underground, designed to shield against cosmic rays and other background radiation. It houses 20,000 tonnes of liquid scintillator, a material that emits light when interacting with particles. The observatory is equipped with 43,200 photomultiplier tubes (PMTs) to detect these light signals, making it the largest detector of its kind in the world.
Design and Functionality of JUNO
The liquid scintillator, specifically linear alkyl benzene, is contained in an acrylic sphere surrounded by PMTs and an additional 60,000 tonnes of ultra-pure water. This arrangement not only enhances detection capabilities but also serves as a radiation shield. The configuration is reminiscent of the Sudbury Neutrino Observatory in Canada but is significantly larger, positioning JUNO as a leader in neutrino research.
One of JUNO’s primary objectives is to measure antineutrinos and observe neutrino oscillations, a phenomenon where neutrinos change between three different types, or “flavors.” These oscillations are linked to the particles’ unknown masses and are crucial for understanding the role of neutrinos in the universe. The facility will also conduct experiments related to neutrinos emitted from nearby nuclear reactors, providing insights into various nuclear processes, including fusion and fission.
A Competitive Landscape in Neutrino Research
While JUNO currently holds the title for the largest neutrino detector, its reign may be short-lived. Japan’s HyperKamiokande is expected to surpass JUNO when it becomes operational in 2028, featuring a capacity of 258,000 tonnes of water. The competition between these two facilities underscores the collaborative spirit of the scientific community, where advancements benefit all researchers through shared discoveries.
As JUNO begins its journey into the depths of particle physics, it holds the promise of unveiling critical mysteries surrounding neutrinos, contributing to our broader understanding of the universe. The implications of this research are profound, potentially illuminating aspects of dark matter and the fundamental forces shaping our reality.
