New experiment allows SNOLAB scientists deep inside Creighton Mine to join the international search for dark matter<\/p>\n
Published Mar 29, 2026 \u00a0\u2022\u00a0 Last updated 2\u00a0hours ago \u00a0\u2022\u00a0 5 minute read<\/p>\n
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The SLAC team inspects an installed tower at the bottom of the dilution refrigerator used for tower testing. (Christopher Smith\/SLAC National Accelerator Laboratory)Article content<\/p>\n
Deep underground in Sudbury\u2019s SNOLAB<\/a>, a major new experiment has just reached a critical milestone. The very centre of a series of large, nested copper vessels that make up the heart of the newest and one of the most sensitive detectors in the world has now reached a temperature a hundred times colder than outer space.<\/p>\n Advertisement 2<\/p>\n This advertisement has not loaded yet, but your article continues below.<\/p>\n Article content<\/p>\n After several years of fabricating and installing, a team of international scientists and SNOLAB staff working on the Super Cryogenic Dark Matter Search<\/a> (SuperCDMS) experiment have successfully cooled the experiment to its base temperature \u2014 just tens of millikelvin<\/a>, or a hundredth of a degree above absolute zero \u2013 or -273.14 degrees C.<\/p>\n Article content<\/p>\n Recommended Videos<\/p>\n Article content<\/p>\n Reaching base temperature marks a major transition for SuperCDMS, from construction and installation to commissioning and science operations. The SuperCDMS experiment is poised to join the international search for dark matter, the elusive sub-atomic particle thought to comprise up to 85 per cent of the mass of the universe.<\/p>\n We know from astrophysical observations that our solar system and Milky Way galaxy sit inside a halo of dark matter, and that dark matter is passing through us all the time. The challenge is to build a detector quiet enough and sensitive enough to observe the very rare interactions of dark matter particles.<\/p>\n At the heart of SuperCDMS are 24 cryogenically cooled detectors made from ultra-pure silicon and germanium crystals, each just larger than a hockey puck. When a dark matter particle strikes one of these crystals, it produces a tiny vibration called a phonon<\/a>, along with a small electrical signal. To detect those minuscule signals, the crystals are outfitted with superconducting sensors that only work when they are extremely cold.<\/p>\n Advertisement 3<\/p>\n This advertisement has not loaded yet, but your article continues below.<\/p>\n Article content<\/p>\n SuperCDMS is optimized to explore a region of dark matter models that has remained largely uncharted: light dark matter, a hypothesized form of matter that interacts so weakly with ordinary matter that it has so far escaped direct detection, says Miriam Diamond, assistant professor<\/a> in the Department of Physics and the Department of Astronomy & Astrophysics, University of Toronto and a SuperCDMS collaborator.<\/p>\n Article content<\/p>\n \u201cWhat sets SuperCDMS apart from other dark matter searches is its low threshold for detecting tiny energy depositions,\u201d Diamond says. \u201cThis gives it exquisite sensitivity to low-mass dark matter candidates, including WIMP-like particles, axion-like particles, dark photons, and lightly-ionizing particles.\u201d<\/p>\n Reaching base temperature is the culmination of years of preparation and months of detailed planning. Over the last year, the team developed a step-by-step cooldown plan, working closely with cryogenics experts responsible for different parts of the system.<\/p>\n \u201cThe detectors simply don\u2019t function unless they\u2019re cold enough to enter the superconducting transition,\u201d said SLAC scientist Richard Partridge<\/a>, who manages the experiment\u2019s installation. \u201cFor us, that means roughly 15 to 30 millikelvin.\u201d<\/p>\n Advertisement 4<\/p>\n This advertisement has not loaded yet, but your article continues below.<\/p>\n Article content<\/p>\n Cooling the experiment reduces thermal noise, the random motion of atoms that can mask faint signals. \u201cWhen everything is that cold, the crystals are basically quiet,\u201d Partridge said. \u201cEven very small energy deposits become detectable.\u201d<\/p>\n![\"SNOLAB\"](\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/03\/cool-2.jpg\")
SNOLAB staff escort the dilution fridge 1.2 kilometers through the mine drift to the lab entrance. (Mike Whitehouse\/SNOLAB)<\/p>\n![\"SNOLAB\"](\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/03\/cool-4.jpg\")
SLAC scientist Richard Partridge inspects the short readout cables connected to the four detector towers, mounted on a support plate. These cables carry tiny electrical signals produced when particles interact in the detectors, allowing scientists to study rare events that could reveal dark matter. (SuperCDMS Collaboration)<\/p>\n
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A peek through the dilution fridge during installation. (Gerry Kingsley\/SNOLAB)About SNOLAB<\/p>\n