Going deep underground in Canada in search of dark matter – by Ivan Semeniuk (Globe and Mail – March 22, 2014)

The Globe and Mail is Canada’s national newspaper with the second largest broadsheet circulation in the country. It has enormous influence on Canada’s political and business elite.

SUDBURY, Ont. — The deeper you go, the higher you fly. The Beatles lyric seems apt while I’m plunging down a mine shaft at 10 metres a second. My ears pop as the open-air elevator descends and the bare rock walls rush past in a blur.

After three minutes we’re two kilometres below ground, and the elevator stops. We’ve finally reached the level of SNOLAB. Located near Sudbury, Ont., it’s one of the world’s deepest laboratories and a place where scientists are hoping to answer a riddle of cosmic proportions: What is dark matter?

Unseen but ever present, dark matter makes up 85 per cent of all the stuff in the universe. Like an invisible conductor, its gravity guides the motions of galaxies and stars. When the universe began, dark matter helped to shepherd atoms together, ultimately making it possible for planets to form and life to emerge. Until we understand dark matter, we won’t really understand why we exist.

Like the Higgs boson, which was confirmed last year, or the gravitational echoes from the Big Bang reported earlier this week, the detection of dark matter would be a Nobel Prize-worthy find – one that would offer a genuinely new piece of information about the nature of reality.

The challenge for physicists is that dark matter can be neither seen nor felt. If it is a particle, it interacts only rarely with the matter world we know. Any detector that is sensitive enough to spot it would be flooded by all the other particles that normally rain down on Earth’s surface from space.

It’s the need to screen out all this noise that has sent researchers far underground. And when a new dark matter detector called DEAP-3600 switches on at SNOLAB later this year, they may finally find what they’re looking for.

“There’s real discovery potential,” says Mark Boulay, a professor of physics at Queen’s University in Kingston and the leader of the DEAP-3600 experiment.

Now it’s time to strip and shower.

After the two-kilometre journey down and a walk almost half that long through the dark passages of the Creighton Mine, operated by Vale Limited, a tunnel branches off and leads to the entrance of SNOLAB.

Passing through a succession of change rooms we leave behind boots, hard hats and all of our clothing before showering down and zipping into clean-room outfits provided by SNOLAB. While the lab is well isolated from space radiation because of its depth, there is radiation – particles of ordinary matter – in the dust that is carried down from the surface or picked up in the mine. That can affect the experiments in SNOLAB, so an elaborate entry protocol is needed to keep the dust at bay.

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