SNOLAB

SNOLAB is a Canadian underground physics laboratory at a depth of 2 km in Vale's Creighton nickel mine in Sudbury, Ontario. The original Sudbury Neutrino Observatory (SNO) experiment has ended, but the facilities have been expanded into a permanent underground laboratory.

File:SNOLAB 2014-03-21.jpg

SNOLAB surface building. It is connected to the underground laboratory by narrow-gauge railway.

Although accessed through a mine, the laboratory proper is maintained as a class-2000 cleanroom, with very low levels of dust and background radiation.

SNOLAB is the world's second-deepest underground lab facility; its 6,800 feet (2,070 m) overburden of 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.

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. With the deepest underground laboratory in North America at 2100 metre water equivalent depth, and the deepest in the world at 4800 m.w.e., many other groups were interested in conducting experiments in the 6000 m.w.e. 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 was briefly the world's deepest underground laboratory, until it was surpassed by the 2.4 km-deep China Jinping Underground Laboratory at the end of 2010. CJPL achieves a muon flux of less than 0.2 μ/m²/day, slightly less than SNOLAB's 0.27 μ/m²/day. (For comparison, the rate on the surface, at sea level, is about 15 million μ/m²/day.)

The planned DUSEL laboratory in the United States, which would have been deeper, was greatly scaled back after the National Science Foundation refused major funding in 2010.

Experiments

As of September 2015 SNOLAB hosts five operating physics experiments:

• The HALO (Helium and Lead Observatory) supernova neutrino detector,
• DAMIC (Dark Matter in CCDs) detector,
• The PICO 2L dark matter search prototype (PICO is a merger of the former PICASSO and COUPP collaborations),
• The second-generation PICO-60 dark matter search, formerly named COUPP-60 and
• The second-generation DEAP-3600 dark matter detector, using 3600 kg of liquid argon, has completed construction and is commissioning, with first physics results expected in 2016.

Four more experiments are currently under construction:

• The SNO+ neutrino detector (using the original SNO experiment chamber),
• MiniCLEAN (Cryogenic Low-Energy Astrophysics with Noble gases) dark matter detector,
• SuperCDMS (Cryogenic Dark Matter Search) dark matter detector, and
• The DAMIC100 detector.

Five experiments have completed and are no longer operating:

• The original heavy water based Sudbury Neutrino Observatory experiment,
• The POLARIS underground project at SNOLAB (PUPS), observing seismic signals at depth in very hard rock,
• The first-generation COUPP 4-kg bubble chamber dark matter search, is no longer in operation.
• The DEAP-1 dark matter search, and
• The PICASSO dark matter search.

Additional planned experiments have requested laboratory space such as the next-generation nEXO, COBRA experiment searches for neutrinoless double beta decay, and the New Experiments With Spheres (NEWS) electrostatic dark matter detector. There are also plans for a larger PICO-250L detector.

The total size of the SNOLAB underground facilities, including utility spaces and personnel spaces, is:

	Excavated	Clean room	Laboratory
Floor space	7,215 m² 77,636 ft²	4,942 m² 53,180 ft²	3,055 m² 32,877 ft²
Volume	46,648 m³ 1,647,134 ft³	37,241 m³ 1,314,973 ft³	29,555 m³ 1,043,579 ft³

External links

• SNOLAB website
• SNOLAB french presentations