  Low-temperature cryogenics open the door for a range of interesting
technologies based on features like superconductivity and superfluidity,
low-temperature phase transitions or the low heat capacity of non-metals in the
milli-Kelvin range. Devices based on these technologies are often sensitive to
small energy depositions as can be caused by environmental radiation. The
Cryogenic Underground TEst facility (CUTE) at SNOLAB is a platform for testing
and operating cryogenic devices in an environment with low levels of
background. The large experimental chamber ($\mathcal{O}$(10) L) reaches a base
temperature of $\sim$12 mK; it can hold a payload of up to $\sim$20 kg and
provides a radiogenic background event rate as low as a few events/kg/keV/day
in the energy range below about 100 keV, as well as a negligible muon rate
($\mathcal{O}$(1)/month). CUTE was designed and built in the context of the
Super Cryogenic Dark Matter Search experiment (SuperCDMS) which uses cryogenic
detectors to search for interactions of dark matter particles with ordinary
matter. The facility has been used to test SuperCDMS detectors since its
commissioning in 2019. In 2021, it was handed over to SNOLAB to become a SNOLAB
user facility after the completion of the testing of detectors for SuperCDMS.
The facility will be available for projects that benefit from these special
conditions, based on proposals assessed for their scientific and technological
merits. This article describes the main design features and operating
parameters of CUTE.
