SNOLAB is a Canadian underground science laboratory specializing in neutrino and dark matter physics. Located 2 km below the surface in Vale's Creighton nickel mine near Sudbury, Ontario, SNOLAB is an expansion of the existing facilities constructed for the original Sudbury Neutrino Observatory (SNO) solar neutrino experiment. SNOLAB is the world's deepest operational clean room facility. Although accessed through an active mine, the laboratory proper is maintained as a class-2000 cleanroom, with very low levels of dust and background radiation. SNOLAB's 2070 m (6800 feet) of overburden rock provides 6010 metre water equivalent (MWE) shielding from cosmic rays, providing a low-background environment for experiments requiring high sensitivities and extremely low counting rates. The combination of great depth and cleanliness that SNOLAB affords allows extremely rare interactions and weak processes to be studied. In addition to neutrino and dark matter physics, SNOLAB is also host to biological experiments in an underground environment.

History

The Sudbury Neutrino Observatory was the world's deepest underground experiment since the Kolar Gold Fields experiments ended with the closing of that mine in 1992. Many research collaborations were, and still are, interested in conducting experiments in the 6000 MWE location. In 2002, funding was approved by the Canada Foundation for Innovation to expand the SNO facilities into a general-purpose laboratory, and more funding was received in 2007 and 2008. Construction of the major laboratory space was completed in 2009, with the entire lab entering operation as a 'clean' space in March 2011. SNOLAB is the world's deepest underground laboratory, tied with the China Jinping Underground Laboratory since 2011. Although CJPL has more rock (2.4 km) above it, the effective depth for science purposes is determined by the cosmic ray muon flux, and CJPL's mountain location admits more muons from the side than SNOLAB's flat overburden. The measured muon fluxes are 0.27 μ/m²/day ( μ/cm²/s) at SNOLAB, and μ/m²/day (3.53 μ/cm²/s) at CJPL, tied to within the measurement uncertainty. (For comparison, the rate on the surface, at sea level, is about 15 million μ/m²/day.) CJPL does have the advantage of fewer radioisotopes in the surrounding rock.

Experiments

, SNOLAB hosts the following experiments:

Neutrino detectors

Dark matter detectors

Biological experiments

Projects under construction

Decommissioned experiments

Future projects

Additional planned experiments have requested laboratory space such as the next-generation nEXO, and the LEGEND-1000 searches for neutrinoless double beta decay. There are also plans for a larger PICO-500L detector. The total size of the SNOLAB underground facilities, including utility spaces and personnel spaces, is: