Understanding our universe and the laws that govern it will not be done lukewarmly and measuredly: at the moment, everything is at stake in the extremes. Scientists are building fusion reactors reaching temperatures surpassing those of the Sun, while the quest for dark matter – this undetected substance making up 85% of all matter in the universe – requires extreme cold, close to absolute zero, recalls Popular Mechanics.
In March 2026, the Super Cryogenic Dark Matter Search (SuperCDMS) experiment, installed at the SNOLAB underground laboratory in an active nickel mine near Sudbury, Ontario, officially reached temperatures a few thousandths of a degree above absolute zero, hundreds of times colder than interstellar space. At this level, thermal motion stops almost completely, which is ideal for tracking a particle that does not absorb light and barely interacts with matter.
SuperCDMS is a cylindrical enclosure measuring 4 meters on each side, shielded in ultrapure lead against gamma rays and in high-density polyethylene against neutrons, all placed 2,070 meters underground. Its detectors, made of silicon and germanium with minimal radioactivity, are designed to identify WIMPs (“weakly interacting massive particles” or weakly interacting massive particles), potential candidates for dark matter.
“Reaching baseline temperature is a major milestone in a multi-year campaign to build a low-background facility capable of accommodating our ultra-sensitive cryogenic detectors”comments Priscilla Cushman, spokesperson for SuperCDMS and professor at the University of Minnesota. At these extreme temperatures, detectors can now explore a new region of the parameter where the lightest dark matter particles would lurk.
Hunting for WIMPs
SuperCDMS follows a series of cryogenic experiments (CDMS) launched in the 1990s, and directly to SuperCDMS Soudan, conducted from 2011 to 2015 at a mine in Minnesota. Under construction since 2018, the new facility surpasses its predecessor in sensitivity, capable of detecting particles half to five times the mass of a proton.
“With many more sensors per detector than in Sudan, new simulation tools and AI-assisted reconstruction, the data will be much richer than expectedrejoices Noah Kurinsky, researcher at the SLAC National Accelerator Laboratory, designer of the detectors. Every day will bring something new; it’s new science from day one.”
The principle is simple: if a dark matter particle hits an atom in the detector’s crystal lattice, it makes it vibrate and releases electrons. In the ultrapure environment of SuperCDMS, scientists will be able to distinguish a WIMP signal and distinguish it from background noise, potentially offering the first direct detection of dark matter, or even the discovery of rare isotopes or novel interactions.
Although the required temperatures are reached, the team still needs to spend a few months calibrating and optimizing the detector channels. After nearly a decade of waiting, the big moment is approaching. If SuperCDMS succeeds, it could redefine our view of the universe, finally confirming the nature of this mysterious dark matter that shapes galaxies and cosmos.
Understanding dark matter could reveal new physical laws, pave the way for technologies unimaginable today and shed light on the very origins of the universe.
