According to the U.S. Department of Energy’s Fermi National Accelerator Laboratory, an international collaboration is currently building the Deep Underground Neutrino Experiment at the Long Baseline Neutrino Facility, representing one of the most ambitious physics experiments ever conceived. Once researchers fill the massive detector modules with liquid argon and seal them, they will lose access to the submerged components for decades, prompting scientists to run an intense stress test on a prototype at CERN.
ProtoDUNE Testing at CERN Pushes Technology to Its Limits
At CERN’s neutrino platform in Europe, two 770-ton-scale prototype neutrino detectors known as ProtoDUNEs are currently demonstrating the technologies planned for the main U.S. experiment, according to Fermilab. Sowjanya Gollapinni, DUNE co-spokesperson and a senior scientist at Los Alamos National Laboratory, described the work at ProtoDUNE as heroic, noting that researchers want to stress test the system to see how it holds up over a long period. Gollapinni stated that neutrinos are key in understanding how the universe evolved and where it is headed.
How Liquid-Argon Time Projection Chambers Capture Neutrinos
To capture neutrinos, scientists are installing massive detectors called liquid-argon time projection chambers a mile underground at the Sanford Underground Research Facility in South Dakota, as reported by Fermilab. When neutrinos interact with the liquid argon, they liberate electrons that are pulled by a strong electric field toward specialized components called readout planes inside the chamber. These readout planes record data from the ionized electrons, allowing scientists to reconstruct the direction and energy of the tracks to determine the position, energy, and identity of the original neutrino, according to the collaboration.
Comparing Anode Plane Assemblies and Printed Circuit Boards
Before building the main experiment, scientists tested two different technologies at the CERN Neutrino Platform, according to Fermilab records. One technique relies on the Anode Plane Assembly, or APA, developed in the 1980s, which uses planes of loom-like wire detectors to collect current from drifting electrons. Flavio Cavanna of Fermi National Accelerator Laboratory noted that this technique is tried and true and that researchers know it works. The second technology replaces wire planes with channels of copper printed onto circuit boards. Steve Kettell, a scientist at Brookhaven National Laboratory and one of DUNE’s technical coordinators, explained that wrapping wires 3,000 times around a frame is challenging, making commercially available printed circuit boards a more efficient choice for the collaboration.
Did you know?
While a standard handheld battery operates at around 1.5 volts, the DUNE vertical drift design scales that concept up to 300,000 volts to maintain the electric field across doubled distances, according to Brookhaven National Laboratory scientist Steve Kettell.
Vertical Drift Design and the 300-Kilovolt Stress Test
The new vertical drift geometry doubles the distance liberated electrons move, allowing scientists to capture and record more neutrinos with fewer components, according to Fermilab. However, this configuration requires a much higher voltage to maintain the electric field. Kettell noted that the team scales the voltage up to 300,000 volts. Last year, the collaboration started commissioning the ProtoDUNE Vertical Drift design, and by June 2025 the detector was ready for launch. Gollapinni reported that the system ran smoothly out of the box, calling the ProtoDUNE Vertical Drift a resounding success thanks to support from the CERN neutrino platform. On May 22, 2026, the team initiated an extended stress test to ramp the voltage up to 300 kilovolts and evaluate how long the detector can hold it before a scheduled completion in the fall. Kettell compared the test to building a lightning storm inside a detector without wanting actual physical lightning strikes, explaining that observing sparks allows researchers to study how all components react under simulated long-term conditions.
Frequently Asked Questions
What is the Deep Underground Neutrino Experiment (DUNE)?
According to Fermilab, DUNE is an ambitious next-generation international physics experiment hosted by the U.S. Department of Energy’s Fermi National Accelerator Laboratory designed to study neutrinos and help scientists understand the evolution of the universe.
Where are the ProtoDUNE detectors located?
The two 770-ton-scale ProtoDUNE detectors are located at CERN’s neutrino platform in Europe, where they test technologies destined for the main detector in South Dakota, according to project documentation.
Why are scientists running a stress test at 300,000 volts?
According to Brookhaven National Laboratory scientist Steve Kettell, the stress test simulates the intense conditions that the vertical drift detectors will face a mile underground, allowing researchers to study component reactions under high voltage since direct access will be impossible for decades after sealing.
Pro Tip for Researchers: Early-career scientists looking to engage with this field can participate in specialized training initiatives like the DUNE Data Analysis School, hosted by Fermilab’s Neutrino Physics Center, which equips analysts with necessary software tools.
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