Belinda Smith

speaker

2,440 appearances 25 recordings 4 series first heard Apr 2026 last heard 5d ago

Belinda Smith’s voice in public audio — every appearance, attributed to the second.

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recordings per month · last 12 months

Recordings per month over the last 12 months — 25 in all, peaking in Jul 2026 with 6.

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That's the super cryogenic dark matter search.

Bunker is showing us an experiment designed to detect particles of dark matter.

Not that you could tell what it's for from its appearance.

At the time of my visit, they were still working on the outer layers of shielding for the experiment.

So it basically looked like an enormous metal cylinder, several meters high and just as wide, and partially hidden behind some pipes and scaffolding.

Deep inside the metal cylinder are the germanium and silicon crystals that act as a target for dark matter particles.

And those crystals have to be kept cold, and I mean really cold, to minimize so-called thermal noise.

And that explains the loud pulsating sound that fills the entire chamber.

The noise is coming from machines called pulse tube coolers, which push high-pressure liquid helium through pipes,

Something like the piston in your car's engine if your car was as cold as outer space.

Here's Ray Bunker again.

The reason it has to be kept so cold is the approach for detecting dark matter here is to use large kilogram-scale germanium and silicon crystals.

Dark matter, we hope, comes along, interacts with an atom in the crystal, vibrates it,

And in order to detect the small amount of vibration, you have to reject all the other vibration.

And you do that by making them very cold.

And so then you have a chance of seeing this very rare interaction of a dark matter particle pinging an atom in your crystal.

Hence the noisy cooling system, which gets those germanium and silicon crystals down to a bone-chilling 15 millikelvins.

That's 15 thousandths of a degree above absolute zero.

SuperCDMS is one of a handful of experiments at SNOLAB that's on the lookout for dark matter.

In particular, these experiments are on the hunt for WIMPs,

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