- The SuperCDMS dark‑matter detector, located 2 km underground in a Sudbury, Ontario mine, has been cooled to 5.3 millikelvin—about 500× colder than the cosmic microwave background.
- This temperature is essential for detecting the tiny energy deposits expected from low‑mass dark matter particles.

- Dark matter makes up ~27% of the universe, yet has never been directly detected.
- SuperCDMS targets lightweight WIMPs (below ~10 proton masses), a mass range where large xenon detectors lose sensitivity.
- At millikelvin temperatures, even tens of electronvolts of energy can be detected as phonons and freed electrons in germanium/silicon crystals.

- SNOLAB’s 2 km of rock reduces cosmic ray muons by a factor of ~50 million, creating one of the quietest environments on Earth for particle physics.
- The C.U.T.E facility at SNOLAB has validated that millikelvin temperatures can be maintained underground.

- Magnetic fields can interfere with SQUID readout electronics; shielding is essential.
- Radon‑reduced air and layered shielding are used to suppress radioactive backgrounds.
- Without these protections, the detector would be overwhelmed by noise.

- Confirmed: The dilution refrigerator can reach 5.3 mK (tested at Fermilab).
- Not yet confirmed: Whether the same temperature has been achieved after installation underground.
- Not yet published: Real background rates or calibration spectra from the final detector configuration.
- Timeline unclear: No official date for when full physics data‑taking will begin.

- Xenon detectors (LZ, XENONnT) dominate the search for heavy WIMPs.
- SuperCDMS and DAMIC‑M explore the low‑mass WIMP region with different technologies.
- Overlapping experiments are essential for confirming any potential signal.

- If no dark matter is detected, SuperCDMS will still tighten exclusion limits and help rule out large regions of parameter space.
- The experiment’s sensitivity makes it one of the few capable of probing very light dark‑matter candidates.