The most elusive particles in the Universe – neutrinos – might not stay hidden for much longer. Testing of the Deep Underground Neutrino Experiment, or DUNE, began earlier this year.
The project aims to create neutrinos from protons hurtling along at almost the speed of light. Those neutrinos will be sent from Fermilab, just outside Chicago, Illinois through the Earth’s rock to the Sanford lab, 1,300 kilometres away, in South Dakota.
While the neutrinos will cover the distance in almost no time at all – not only do they travel near the speed of light but they very, very rarely interact with anything on their journey to slow them down – it will be enough for them to switch flavour – that is, on a quantum scale – between muon, tau and electron.
Most neutrinos sent from the Fermilab will be the muon type. But as they barrel through the Earth and flip flavours, DUNE will “taste” their flavour along the way.
The final detector, in South Dakota, will be filled with super-cold liquid argon. As neutrinos interact with argon atoms, they’ll create charged particles. These charged particles will, in turn, jostle electrons from argon atoms.
The electrons, being negatively charged, will be scooped along an electric field, collected and analysed.
So why bother? Hopefully, they’ll help answer one of physics’ biggest conundrums: how the Universe expanded just after the Big Bang.