Dune, the Deep Underground Neutrino Experiment (DUNE) just broke ground at their soon to be new facility that will unlock the secrets of the illusive neutrino particle.
The US $1 billion project is currently being upgraded with new detectors hundreds of kilometers from the main facility in Chicago. Nearly 1300 km away underneath the lab, researchers are installing new detectors over 1.5 kilometers below the surface of the Earth.
Subatomic particles will be shot from Chicago to the Sanford lab through the Earths mantle where the massive detectors will detect the particles hundreds of kilometers away.
DUNE experiment and facilities [Image Source: DUNE]
Neutrinos are subatomic particles with many similarities to the electron, only neutrinos carry no charge and are incredibly light. The particles are some of the most abundant in the universe, yet they rarely interact with matter. According to Scientific American, “A low-energy neutrino will travel through many light-years of normal matter before interacting with anything.”
Detecting the particles is an immensely difficult challenge. However, recent discoveries about neutrinos is helping scientists better understand the fundamental properties of matter, energy, space and time.
“They could also unveil new, exotic physical processes that have so far been beyond our reach,” explains DUNE.
Over the last few decades, researchers have slowly, and painstakingly, have been discovering the states – or flavors – of neutrinos. Current research indicates three flavors that have the ability to transform from one flavor to another.
“These results indicate that each neutrino flavor state is a mixture of three different nonzero mass states, and to date offer the most compelling evidence for physics beyond the Standard Model. In a single experiment, DUNE will enable a broad exploration of the three-flavor model of neutrino physics with unprecedented detail,” DUNE describes on their online website.
The new detectors currently being installed beneath will give a rare glimpse into the properties created during the birth of a neutron star. Furthermore, in the future, the project may also help scientists witness the birth of a black hole.
Particle detectors can detect the neutrinos emitted by supernova, in this instance, from the supernova SN1987A. [Image Source: DUNE]
Scientists hope that by unraveling the secrets of the neutrino, they will be able to deduce how matter formed in the early days of the universe. Then, the research may be used to create new and exotic physical processes that have thus far eluded the scientific community at large.
Perhaps, even more radically, researchers hope the new discoveries will help unify and describe all the known forces under one equation. The research.
How DUNE will detect neutrinos
As previously described, neutrinos have the impeccable ability to travel through dense matter, such as the mantle of the Earth, without interacting with any atoms. As they pass through, they leave behind no trace. Observing even a single interaction requires a massive detector that must operate for many years.
The DUNE far detector
Unlike most detectors which use heavy water, the Dune Far detector will use a “state-of-the-art Liquid Argon Time-Projection Chamber (LArTPC) technology for the massive neutrino detector planned at the Sanford Lab site,” according to DUNE.
The Dune Far Detector currently being installed 1,475 meters underground at the Sanford Underground Research Facility in Lead, South Dakota. [Image Source: DUNE]
Four cryostat detectors located at Dune Far will hold a combined total of 70,000 tons of liquid argon which will act as the target for the neutrinos emitted over 1000 kilometers away. To keep the argon in a liquid state, a central cooling unit keeps the liquid at a freezing -184 degrees Celsius
Four cryogenic detectors containing 17,000 tons of argon each act as the target for the neutrinos. A central cooling unit keeps the argon at 184 degrees Celsius below zero. [Image Source: DUNE]
Inside the detector are wire planes that indirectly measure the number and energy levels of every collision that takes place. The detectors send the signals to a system which interprets the data, accurately mapping out the trajectory of an individual neutrino interaction.
Wire planes indirectly detect neutrino interactions with argon. [Image Source: DUNE]
When a neutrino interacts with the argon in the detector, muon and proton particles are ejected. Then, the ejected particles knock electrons loose from the liquid argon. The charge can then be detected by the wire planes. The interaction leaves behind particle tracks which a sophisticated computer system compiles into a visual image with the input of the collected data.
Particle trace created after a neutrino interacts with liquid argon. [Image Source: DUNE]
The video below demonstrates the what happens when a neutrino interacts with argon.
Shielding the detectors from cosmic rays
Burying the detectors over a kilometer underground seems overkill, although it is entirely necessary to shield the detectors from cosmic rays. Cosmic rays originating from outer space continuously bombard the upper atmosphere with high-energy particle – typically protons. Every interaction releases a shower of particles which stream down to Earth.
The detectors are ultra sensitive, and the high-energy particles carry enough energy to disrupt or damage the detectors. The particles shower down so often, DUNE predicts that “cosmic-ray muons pass through your hand at a rate of more than one per second.”
Neutron physics is still in its infancy, however, many more detectors are continuously being constructed around the world. Although the elusive particles still remain a large mystery, scientists hope that with the new DUNE detector additions and other experiments, scientists will be able to piece together the inner workings of particles and the universe as we know it.