SuperCDMS begins hunt for light dark matter

The Super Cryogenic Dark Matter Search (SuperCDMS) SNOLAB experiment has commenced its initial scientific data-taking phase. According to a report from Stanford University, this early-science period, which began in August 2026, involves 24 ultra-pure silicon and germanium crystals chilled to near absolute zero more than a mile underground.

Tina Cartaro, SuperCDMS operations manager at SLAC National Accelerator Laboratory, stated that the search for dark matter at the facility is finally underway. She noted that even in this early phase, the most sensitive detectors have the potential to deliver breakthrough discoveries. The team is simultaneously preparing and testing the entire system to learn how the detectors and cryogenic cooling perform together.

SuperCDMS is an international collaboration of 28 institutions, with SLAC serving as the lead laboratory. This second-generation experiment is specifically designed to detect hypothetical "light" dark matter particles. These particles are so lightweight that their interactions with ordinary matter leave only the faintest traces, making them exceptionally difficult to detect.

How the Detector Operates

The experiment is located in SNOLAB, a deep underground laboratory within the Vale Creighton mine near Sudbury, Ontario. Each of the 24 crystals is approximately the size of a hockey puck and housed inside a refrigerator colder than outer space. The detection principle relies on a dark matter particle striking a crystal, which would produce a tiny vibration called a phonon along with a small electrical signal.

To capture these minuscule signals, the crystals are equipped with superconducting sensors that function only at extremely low temperatures. The entire apparatus is surrounded by multiple layers of clean shielding materials. This shielding includes copper, polyethylene, ultrapure lead, and a barrier against radon to prevent stray background radiation from overwhelming any potential dark matter signal.

The Path to Full Sensitivity

The early-science phase is scheduled to continue through the fall of 2026. Following this initial data-taking period, the collaboration plans to warm up the experiment. This warm-up and maintenance period, expected to last into late 2026, will allow for further optimization of both the cryogenic system and the noise environment. A full year of data collection with the detectors running at optimized, full sensitivity is then planned.

Priscilla Cushman, SuperCDMS spokesperson and a professor at the University of Minnesota School of Physics and Astronomy, said the detectors will explore regions where the lightest-mass dark matter particles may be lurking with unprecedented sensitivity. She stated this opens up new avenues in the search for dark matter, which constitutes approximately 85% of all matter in the universe.

The shielding for the experiment includes tiles made from ultrapure lead sourced from ancient sunken ballast in the Mediterranean, with additional layers of ordinary lead added on top.