To find the most elusive subatomic particles in the universe, China is developing a detector that will be buried deep beneath the ocean’s surface. Tens of trillions of these phantom neutrinos pass through the Earth (and your body) every second without coming into contact with anything. The nucleus of a stray atom will occasionally collide with these neutrally charged particles, producing an almost imperceptible flare of light.
In addition to letting them know that a neutrino was present, this flash of light also enables them to speculate as to its possible source. Atoms fuse together deep inside the sun during nuclear processes, producing some neutrinos. The neutrinos produced by such fusion processes leave the sun in a matter of seconds. Nuclear fission, which occurs in nuclear reactors, is one source of certain neutrinos. The Department of Energy claims that neutrinos can even be released by the potassium decomposing within a banana. Moreover, neutrinos were just discovered for the first time at the Large Hadron Collider by scientists.
Yet, some neutrinos are solar system-external. These high-energy neutrinos could have come from supernovas, pulsars, black holes, or some other undiscovered event. Researchers from the Chinese Academy of Sciences are looking for these high-energy neutrinos. According to Chen Mingjun, the project’s main researcher, the new detector would consist of 55,000 sensors hung 0.6 miles (1 km) below the ocean’s surface, according to Xinhua Net, China’s official news agency. The sensors will be able to identify neutrinos and distinguish them from solar neutrinos because the sun’s beams can’t penetrate that far into space.
The likelihood of detecting neutrino signals will rise thanks to the pure water, according to Chen. In order to more accurately locate the erratic flashes of light that disclose a neutrino, scientists must construct neutrino detectors in regions with a lot of transparent materials. There are currently detectors, such as the National Science Foundation’s IceCube Neutrino Observatory in Antarctica, which has 5,160 sensors and covers an area of around 0.2 cubic miles (1 cubic kilometers), nearly a mile below the ice. The ice is sufficiently clear down there for the sensors to detect the minute flashes of light.
Not all undersea neutrino detectors will be like the Chinese one. At the deepest lake in the world—Lake Baikal in Siberia—Russia is constructing the Baikal Gigaton Volume Detector (Baikal-GVD). Lastly, a multi-institutional cooperation called the European Cubic Kilometer Neutrino Telescope will be looking for neutrinos in the Mediterranean Sea. Another multi-institutional project, the Pacific Ocean Neutrino Experiment, is developing a detector in the Pacific Ocean off the Canadian province of British Columbia.
The Chinese detector, on the other hand, will be far larger. Chen estimates that its 55,000 sensors will cover around 7 cubic miles (30 cubic kilometers). The detector’s specific purpose would be to determine whether gamma rays and high-energy neutrinos come from the same intergalactic source. The China Giant High Altitude Air Shower Observatory observed gamma rays in 2021, which experts believe originated in the same location as cosmic rays, or high-speed subatomic particles from beyond the solar system. If the researchers found neutrinos from the same source, “we will be able to establish the origin of the cosmic rays,” Chen added.