Photo by Gerry Kingsley
SNOLAB is a unique world-class international facility for deep underground science, located 2km underground in the Vale Creighton mine, near Sudbury, Ontario. The science programme at SNOLAB is primarily focussed on sub-atomic and astro-particle physics, specifically the search for the dark matter that makes up 23% of the matter in the Universe, and the study of neutrino properties and sources, such as the neutrino mass, mixing angles and terrestrial, solar and supernova production sites. This programme requires a variety of detector technologies but both fields ultimately require multi-tonne detectors that can operate in the ultra-low radioactivity background environment that SNOLAB provides. These particle detectors utilise a variety of target materials including liquid scintillator, liquid argon, solid and liquid gels, and are generally built through large, international, multi-institutional collaborations. The required support infrastructures for these experiments have, in many cases, projected lifespans of many years. Other research opportunities are occurring in areas such as rock characterisation, geotechnology, geochemistry and subsurface microbiology, which are being explored as potential future activities.
The great depth at which SNOLAB is located is required to shield these sensitive detection systems from the ubiquitous cosmic radiations that bombard the surface of the planet. By placing 2km of rock between the detectors and the surface these cosmic rays are sufficiently attenuated, by a factor of 50 million down to one cosmic ray muon every day per 4m2, that the rare and exquisite signals from the science of interest can be separated from the signatures from other backgrounds.
The facility includes a surface building which houses offices, conference rooms, IT systems, clean-rooms, electronics labs, warehousing and change rooms. The underground facility is located at a depth of 2070m and comprises 5000m2 of clean room facility, at better than Class2000, including three large detector cavities. In addition to the required health and safety systems and user support services, support infrastructure for experiments within the underground laboratory include HVAC, electrical power, ultra-pure water, compressed air, radiological source control, radio-assay capability, chemistry lab, I.T. and networking, and materials handling and transportation. The very specific requirements of developing and operating experiments in an underground laboratory are supported by a staff of ~50 covering business processes, engineering design, construction, installation, technical support and operations. The SNOLAB scientific research group connects to the experiments and provides expert and local support, as well as undertaking research in its own right as full members of the research collaborations.
The construction phase of SNOLAB was supported by capital funds totalling $70M, including an initial $38.9M capital award from the CFI through the International Joint Venture programme. These funds were managed by Carleton University on behalf of the SNOLAB Institute members. The Ontario Innovation Trust, the Northern Ontario Heritage Fund and FedNor provided the remaining funds for the construction. Operating costs have subsequently been supported by CFI, NSERC, Ontario ORF-RE and by the member institutions. The City of Greater Sudbury is supporting public education.