Deep Underground, a New Hunt for Dark Matter Begins
Scientists have switched on one of the world's most sensitive dark matter searches. The Super Cryogenic Dark Matter Search (SuperCDMS) SNOLAB, located more than a mile beneath Earth's surface in the Vale Creighton mine near Sudbury, Ontario, has begun collecting its first scientific data.
Dark matter is thought to make up about 85% of all matter in the universe, yet it remains elusive because it interacts so faintly with ordinary matter. SuperCDMS SNOLAB is designed to detect a particular class of these hypothetical particles: so-called "light" dark matter, whose interactions leave only the faintest traces.
"The search for dark matter at SuperCDMS SNOLAB is finally underway," said Tina Cartaro, SuperCDMS operations manager at the U.S. Department of Energy's SLAC National Accelerator Laboratory. "Even in this early phase, our most sensitive detectors have the potential to deliver breakthrough discoveries."
The experiment is housed in SNOLAB, a deep underground laboratory in the Vale Creighton mine. It uses 24 ultra-pure silicon and germanium crystals, each about the size of a hockey puck. The crystals sit inside a refrigerator colder than outer space, chilled to near absolute zero. If a dark matter particle strikes one of these crystals, it produces a tiny vibration called a phonon, along with a small electrical signal. Superconducting sensors, which operate only at extremely low temperatures, are attached to the crystals to detect these minuscule signals.
A Phased Approach to Discovery
The current early-science phase will continue through fall 2026. During this period, the team is fine-tuning the system and testing how the detectors and cryogenic cooling perform together. A warm-up and maintenance period is expected to last into late 2026, followed by a year of data collection. The full-scale search is set to begin in 2027.
Although the experiment is not yet running at full sensitivity, it could still deliver meaningful results. "Our detectors will explore, with unprecedented sensitivity, regions where the lightest-mass dark matter particles may be lurking," said Priscilla Cushman, SuperCDMS spokesperson and professor at the University of Minnesota School of Physics and Astronomy. "This opens up new avenues in the search for dark matter."
The team is also learning how to unlock the detectors' design sensitivity, according to Cartaro. "We're preparing and testing the entire system, learning how our detectors and cryogenic cooling perform together so we can unlock their design sensitivity," she said.
A Global Collaborative Effort
SuperCDMS is an international collaboration of 28 institutions, with SLAC serving as the lead laboratory. The project is jointly funded by the U.S. Department of Energy Office of Science, the U.S. National Science Foundation, the Canada Foundation for Innovation, the Natural Sciences and Engineering Research Council of Canada, and the Arthur B. McDonald Institute (Canada).
The experiment is a second-generation search, building on earlier efforts to detect dark matter particles. By operating deep underground and at cryogenic temperatures, scientists aim to reduce background noise and improve their chances of catching the faint signals that light dark matter particles would leave behind.