Frequently asked questions

Questions about neutrinos

Neutrinos are tiny, harmless particles that are among the most abundant — yet least understood — in the universe: they are a billion times more abundant than the particles that make up stars, planets and people. These tiny particles have no electric charge and mostly pass right through the atoms that make up ordinary matter, very rarely interacting with it. Therefore, not only are they harmless, but very challenging to observe!

Experiments carried out over the past half-century have revealed that the three known types of neutrinos can transform into another. These Nobel Prize-winning discoveries have put neutrinos in the spotlight for further research into several fundamental questions about the nature of matter and the evolution of the universe.

Neutrinos were created in vast numbers just after the Big Bang, and they also are being produced in large numbers in stars and inside our Earth. Even bananas emit neutrinos. Neutrino experiments help answer our questions about the origins of the universe, as well as questions about energy and matter. The Deep Underground Neutrino Experiment (DUNE) is an international, world-leading experiment hosted by the U.S. Department of Energy’s Fermilab that will advance our understanding of neutrinos. DUNE aims to find out, for example, whether neutrinos are the key to solving the mystery of how the universe came to consist of matter rather than antimatter. The Long-Baseline Neutrino Facility (LBNF) will provide the neutrino beam for this experiment and the facilities to house and support it.

In addition to studying neutrinos from the beamline at Fermilab, the DUNE detector is being designed to catch neutrinos emerging from exploding stars (supernovae), allowing us to peer inside a star as it dies and collapses into a neutron star and perhaps transforms into a black hole. Scientists also will use the DUNE detector to look for rare subatomic interactions predicted by theories inspired by Albert Einstein’s search for a Grand Unified Theory. This 4-minute video explains the science of DUNE in more detail.

Scientists from around the world consider the scientific goals of the DUNE among the most important research efforts in particle physics, rivaling the discovery of the Higgs particle at the Large Hadron Collider in Europe in 2012.

Yes. Neutrinos are safe. Trillions of neutrinos from the sun go through your body every second without causing harm. Even your body generates neutrinos. Neutrinos do not emit radiation, they don’t create heat, and they don’t change the properties of materials through which they travel. Neutrinos are all around us: Each second, more than a trillion neutrinos from the sun, traveling close to the speed of light, pass through your body without any effect.

Fermilab has operated neutrino-producing facilities for more than 30 years. For more than 10 years, the laboratory has been sending neutrinos from Fermilab in Batavia, Illinois, through the ground to research facilities in Minnesota.

Yes, it will be completely safe. Neutrinos neither create heat nor change the properties of the material they travel through. The number of neutrinos arriving at the DUNE detectors in South Dakota will be less than the number of solar neutrinos going through the detectors.

For the Deep Underground Neutrino Experiment, scientists will use one of Fermilab’s existing particle accelerators, the Main Injector, to make neutrinos. The Main Injector has made neutrinos for other experiments at Fermilab since 2004. It propels protons close to the speed of light and smashes them into a piece of graphite where they collide with atoms in the material, producing secondary particles. The particles that emerge from these collisions generate neutrinos. Watch this short video that explains the neutrino-making process. The construction of a new neutrino beamline for DUNE part of the Long-Baseline Neutrino Facility project.

Neutrinos travel in a straight line. Since the Earth is round, Fermilab will point the neutrinos at an angle into the ground and send them in the direction of the particle detector at Sanford Lab. The neutrinos will leave the Fermilab site at a depth of about 200 feet, cross about 10 miles deep underneath the Mississippi river and reach a maximum depth of close to 20 miles as they travel to South Dakota. No tunnel is necessary to send the neutrinos from Fermilab to South Dakota since neutrinos can travel straight through rock!

No. Neutrinos do not affect rock, soil, water or anything else they travel through.

Questions about DUNE and LBNF activities at Fermilab

Yes. Fermilab built similar infrastructure for the Fermilab-to-Minnesota neutrino project in the early 2000s, and Fermilab has built and operated particle accelerators for more than 40 years.

Yes. The neutrino-making process on the Fermilab site creates very short-lived particles that decay quickly as well as small amounts of tritium, a weakly radioactive form of hydrogen with a half-life of 12.3 years. These byproducts are created when the primary proton beam strikes the piece of graphite, and they are trapped by surrounding concrete and rock. These lifetimes are much shorter than the million-year-long lifetimes of some of the radionuclides produced at nuclear reactors. Fermilab has no nuclear reactors or other nuclear facilities and thus produces none of the radionuclides with million-year-long lifetimes.

Radionuclides created by our particle accelerators rapidly decay into lighter particles until everything has been transformed into stable atoms and electrons. For many types of radionuclides, this takes only hours; for others, such as tritium, it takes years. The small amount of energy (radiation) produced in the decay of these particles gets absorbed as a small amount of heat by the concrete shielding surrounding the area in which these particles are produced.

Fermilab has safely operated particle beams and neutrino-making facilities at Fermilab for more than 30 years. The new Long-Baseline Neutrino Facility will be similar to existing ones at Fermilab.

We have a website that we use to post our latest tritium measurements to keep our neighbors informed about the low levels of tritium produced at Fermilab and the very low levels of tritium that can be found in surface waters on the Fermilab site.

The LBNF project comprises the construction of four buildings, a 58-foot-high hill made of compacted soil, a 680-foot-long tunnel on the Fermilab site to house the equipment to make the neutrinos, a 635-foot-long particle decay pipe, two approximately 200-foot-deep access shafts and an underground hall for a particle detector on the Fermilab site. All of this will be located in the western area of the Fermilab site, close to Kirk Road in Batavia, Illinois. One of the buildings, about 50 feet wide, 135 feet long and 40 feet high, will be constructed close to Giese Road and Kirk Road in Batavia, on the Fermilab site. The buildings on top of the shafts provide the access to the underground halls. See this graphic for the overall layout of the facility at Fermilab.

Groundbreaking for the portion of the project on the Fermilab site took place in November 2019. Initial prep work for the construction on the Fermilab site was completed in 2020. More prep work on the Fermilab site will take place from November 2023 to about March 2024. The start of construction at Fermilab is expected to occur in late summer/early fall 2025.

Some parts of the construction at Fermilab could affect neighbors living close to the construction site. There will be construction noise, and residents living very close to the construction site might notice vibration associated with the blasting that is necessary for the construction of the approximately 200-foot-deep shaft and underground hall near Kirk Road and Giese Road. The construction of the shaft will require blasting several times per day for about 14 months. Fermilab will work with contractors to minimize the impact on its neighbors. Since the blasting could lead to noticeable vibration levels in nearby houses, Fermilab plans to offer pre-construction surveys of nearby homes and will consider installing noise and vibration monitors in the residential area across the construction site.

The construction of the entire Fermilab portion of the facility is expected to occur over a time period of about six years that is expected to begin in summer or fall of 2025.

No. Operation of the new facility will be similar to the operation of existing facilities at Fermilab. Operational noise impacts will be low and limited to chillers and air handling equipment.

Questions about DUNE and LBNF activities at Sanford Lab

At the Sanford Underground Research Facility (Sanford Lab), the LBNF project team will build one service building on the surface and three large underground caverns on the 4850-foot level of the existing facility. Construction will require the excavation of approximately 530,000 cubic yards (850,000 tons) of rock from underground areas. The new underground caverns will hold a large particle detector modules filled with liquid argon, a material similar to helium, but heavier.

The groundbreaking ceremony at Sanford Lab took place on July 21, 2017. In 2018, the project team carried out the prep work necessary prior to the excavation of the deep underground caverns. This includes the prep work for a conveyor system that will transport rock from the Ross shaft at Sanford Lab to the Open Cut. Excavation of the caverns at the 4850-level started in 2019 and will be completed in 2024.

The construction at Sanford Lab will be mostly underground. Aboveground construction of the conveyor system and a building will result in temporary noise increase, including noise from blasting that is necessary to build the conveyor system. There will be increased truck traffic during the construction of the experiment.

No. Operation of the DUNE experiment will be similar to the operation of existing experiments at the Sanford Underground Research Facility. No radiation will be produced at the Sanford facility. Operation of the Cryogen Support Building will increase noise slightly above existing nighttime ambient noise levels around the Ross shaft complex.

More questions

With the help of a number of technical experts, including independent consultants, the Department of Energy prepared an Environmental Assessment document for the project, including the investigation of potential impacts to human health and the environment. The DOE initiated the environmental assessment in May 2013 and released the draft environmental assessment in June 2015 for public comment. Public meetings were held in Illinois and in South Dakota. In October 2015, DOE issued the final environmental assessment and determined that the project will have no significant impact. The Finding of No Significant Impact (FONSI) document is available.

Fermilab and Sanford Lab provide updates on the project through articles on the Fermilab and Sanford Lab websites as well as newsletters, social media, occasional letters to neighbors, press releases, public meetings and other forms of communication. We have set up a webpage for our neighbors in Illinois and a webpage for our neighbors in South Dakota where you can submit questions and concerns throughout the construction of the project. We also update this FAQ webpage with the latest information.

For more information, please read our fact sheet or contact the Fermilab Office of Communication (630-840-4283) or the Sanford Lab Communications Department (605-722-4025).