This is the sixth and final article in the Detector Deep Dives series. After covering Super-Kamiokande, IceCube, SNO, Borexino, and KATRIN, we close with the most ambitious neutrino experiment ever built: DUNE, the Deep Underground Neutrino Experiment.
The two ends
DUNE is a long-baseline experiment. The near detector sits at Fermilab in Batavia, Illinois. The far detector sits 1,300 km away at Sanford Underground Research Facility (SURF) in Lead, South Dakota — the same lab where Ray Davis’s chlorine experiment ran in the 1960s, in the same Homestake gold mine.
A muon-neutrino beam (or, in alternate running, muon-antineutrino) is produced at Fermilab by the Long-Baseline Neutrino Facility (LBNF). It travels through 1,300 km of solid Earth — no tunnel; neutrinos pass straight through rock — and is intercepted by the far detector 1.5 km underground in South Dakota.
Along the 1,300 km baseline, the neutrinos oscillate. The oscillation pattern depends on the mass-ordering, on the CP-violating phase $\delta_{CP}$, and on matter effects from the long path through Earth’s crust and mantle.
The far detector — liquid argon TPC
The DUNE far detector consists of four 17-kiloton-fiducial liquid-argon time projection chambers (LArTPC). Each module is housed in a cryostat about 18 m wide × 19 m tall × 66 m long. Total fiducial mass: about 70 kilotons. Total argon volume: about 100 kilotons.
A liquid-argon TPC works like this. Liquid argon fills the volume. When a charged particle traverses it, the argon is ionized along the track. A uniform electric field (about 500 V/cm) drifts the ionization electrons across meters of liquid argon — slowly, taking a few milliseconds — to readout wires on one face. The pattern of ionization recorded at the wires, combined with timing from prompt scintillation light (also produced by argon), gives a full 3D image of every charged particle in the event.
The imaging is millimeter-scale. Tracks are resolved with resolution comparable to a bubble chamber, but in a detector hundreds of times larger and electronically read out. Electron-vs-photon discrimination, muon vs charged pion tagging, vertex localization for proton decay — all are dramatically better than water Cherenkov can deliver.
The near detector
The near detector at Fermilab is much smaller but no less ambitious. It must characterize the unoscillated beam with high precision before the neutrinos have had a chance to oscillate over the long baseline. Three sub-detectors will operate together:
- ND-LAr: A modular liquid-argon TPC (1.7 kilotons fiducial), the same technology as the far detector — same systematics translate.
- TMS (downstream muon spectrometer): Tracks high-energy muons.
- DUNE-PRISM capability: ND-LAr and TMS can move off-axis on rails, sampling the beam at different angles to control the flux uncertainty.
The beam
The Long-Baseline Neutrino Facility produces neutrinos by firing 120 GeV protons from Fermilab’s Main Injector onto a graphite target. Pions and kaons from the target are focused by magnetic horns into a long decay tunnel, where they decay to muons + (anti)neutrinos. The muons are absorbed in rock; the neutrinos travel on.
The beam power: 1.2 MW initially, upgrading to 2.4 MW in the late 2020s once the PIP-II proton accelerator upgrade is complete. The 2.4 MW upgrade is what makes the full CP-violation reach possible.
The physics targets
CP violation: Measure the difference between $\nu_\mu \to \nu_e$ and $\bar\nu_\mu \to \bar\nu_e$ oscillation probabilities at the far detector. The CP-violating phase $\delta_{CP}$ controls this asymmetry. DUNE alone should reach 5σ sensitivity for a substantial fraction of the possible $\delta_{CP}$ range after ~10 years of running.
Mass ordering: The 1,300 km baseline crosses through significant Earth-matter density. The MSW effect interacts differently with neutrino vs antineutrino oscillation depending on whether the mass ordering is normal or inverted. DUNE’s mass-ordering determination is independent of, and complementary to, JUNO’s reactor-baseline approach.
Supernova neutrinos: A galactic core-collapse supernova would produce thousands of events in DUNE within ~10 seconds. Unlike water Cherenkov detectors that mostly see antineutrinos, DUNE’s argon is preferentially sensitive to electron neutrinos via the $\nu_e + {}^{40}\text{Ar}$ charged-current channel. This makes DUNE the leading detector for the burst-neutronization phase of a supernova — the early-arrival neutronization burst when the proto-neutron-star forms.
Solar neutrinos: DUNE’s threshold can reach low enough to study solar ⁸B neutrinos via $\nu_e + {}^{40}\text{Ar}$.
Proton decay: Searches for proton decay via $p \to \bar\nu K^+$ — a channel where DUNE’s LArTPC imaging is dramatically more sensitive than water Cherenkov.
Beyond Standard Model: Sterile-neutrino searches, non-standard interactions, baryon-number-violating processes.
The timeline
Construction is multi-stage:
- Excavation (2017-2023): Three large caverns excavated 1.5 km underground at SURF.
- Module 1 fill (2027-2028): Cryostat complete, liquid argon fill begins.
- First module operations (2028-2029): Initial physics with atmospheric neutrinos and supernova-readiness; no beam yet.
- LBNF first beam (early 2030s): Long-baseline physics begins.
- Modules 2-4 (early-to-mid 2030s): Phased deployment.
- PIP-II 2.4 MW beam (mid 2030s): Full design power.
By the late 2030s, DUNE should reach its design sensitivity for CP violation and the mass ordering.
Complementarity with Hyper-Kamiokande
Hyper-K and DUNE are not competitors but complementary. Their differences:
- Baseline: Hyper-K is at 295 km from J-PARC; DUNE is at 1,300 km from Fermilab.
- Detector tech: Hyper-K is water Cherenkov; DUNE is liquid-argon TPC.
- Beam energy: Hyper-K’s beam peaks at ~0.6 GeV; DUNE’s beam peaks at ~2-3 GeV with a broad spectrum.
- Sensitivity: Hyper-K excels at high-statistics, low-systematics CP measurements; DUNE excels at matter-effect resolution and event-by-event imaging.
Combining the two gives the strongest possible measurement of the three-flavor PMNS parameters and the cleanest possible discovery of CP violation in the neutrino sector. The combination is expected to reach 5σ CP-violation discovery for most of the $\delta_{CP}$ range by the late 2030s.
What DUNE will not be
DUNE will not measure the absolute neutrino mass (that’s KATRIN, Project 8, and CMB-S4). It will not determine Majorana vs Dirac (that’s 0νββ experiments like LEGEND, KamLAND-Zen, nEXO). It will not study cosmic high-energy neutrinos (that’s IceCube and KM3NeT).
What DUNE will do is settle, with high precision and complementary systematics, the remaining standard-three-flavor parameters: CP violation, mass ordering, and the matter-induced oscillation asymmetry. Combined with Hyper-K, this will give the leptonic sector its most complete experimental picture.
The bottom line
DUNE is the largest, most expensive, and most ambitious neutrino experiment yet attempted. The $3-5 billion budget, the 1,300-kilometer baseline, the four 17-kiloton far-detector modules, the 2.4 MW beam, and the underground caverns 1.5 km below South Dakota all serve one experimental goal: a definitive measurement of CP violation in the lepton sector. If that measurement reveals a non-trivial $\delta_{CP}$, it could be a piece of the puzzle for leptogenesis and the matter-antimatter asymmetry of the universe.
The 2030s are going to be when neutrino physics gets its most consequential answers. DUNE will be the detector providing many of them.
This concludes the Detector Deep Dives series. For chronological context on the experiments covered, see the Neutrino History series. For the beginner-friendly conceptual primer, see Neutrinos 101. For the interactive map of all major neutrino detectors worldwide, see our detector map.
Frequently asked
What is DUNE?
The Deep Underground Neutrino Experiment — an international long-baseline neutrino experiment. A muon-neutrino beam from Fermilab in Illinois is sent 1,300 km through the Earth to a 70-kiloton liquid-argon detector at Sanford Underground Research Facility in South Dakota. The goals: measure CP violation in the neutrino sector, determine the mass ordering, search for proton decay, and detect a galactic supernova.
Why liquid argon time projection chambers?
LArTPCs give millimeter-scale imaging of every charged particle in the detector volume — far better tracking than water Cherenkov can deliver. This lets DUNE distinguish electron neutrinos from neutral-current backgrounds with high efficiency, crucial for measuring CP violation. Argon is also a noble gas, easy to purify, and dense enough for good event rates at reasonable cost.
When does DUNE start operating?
Far detector module 1 is scheduled to be operational in 2028-2029, with first physics around 2030 and first neutrino beam from the Long-Baseline Neutrino Facility (LBNF) in the early 2030s. Full DUNE operations with all four modules and a 2.4 MW upgraded beam are expected in the mid-to-late 2030s.
How does DUNE compare to Hyper-Kamiokande?
They are complementary. Hyper-K is a water Cherenkov detector with much larger fiducial volume but worse imaging. DUNE has better event-by-event particle identification. The two experiments will measure CP violation with different systematics and largely independent backgrounds. Combining them will give the definitive standard-three-flavor picture by the late 2030s.
Cite this article 5 formats
APA
Neutrino Times Editorial Team. (2026, February 18). Detector Deep Dives — Part 6: DUNE, the long-baseline future. Neutrino Times. https://neutrino-times.com/articles/detector-deep-dives-part-6-dune/
Chicago
Neutrino Times Editorial Team. "Detector Deep Dives — Part 6: DUNE, the long-baseline future." Neutrino Times, February 18, 2026. https://neutrino-times.com/articles/detector-deep-dives-part-6-dune/.
MLA
Neutrino Times Editorial Team. "Detector Deep Dives — Part 6: DUNE, the long-baseline future." Neutrino Times, 18 Feb. 2026, https://neutrino-times.com/articles/detector-deep-dives-part-6-dune/.
BibTeX
@misc{neutrino-times-detector-deep-dives-part-6-dune,
author = {Neutrino Times Editorial Team},
title = {Detector Deep Dives — Part 6: DUNE, the long-baseline future},
howpublished = {Neutrino Times},
year = {2026},
month = {feb},
url = {https://neutrino-times.com/articles/detector-deep-dives-part-6-dune/},
note = {Accessed: 2026-02-18}
} RIS
TY - GEN TI - Detector Deep Dives — Part 6: DUNE, the long-baseline future AU - Neutrino Times Editorial Team PY - 2026 DA - 2026-02-18 PB - Neutrino Times UR - https://neutrino-times.com/articles/detector-deep-dives-part-6-dune/ ER -