Listening out for neutrinos

Acoustic neutrinos

A lotta neutrino detectors work by looking for the flares ‘n’ flashes of light generated on the rare occasion a neutrino smashes into something solid, like an atom.  Ya need to do a lotta lookin’ though, which is why neutrino detectors sit in vast pools of water or are dropped into the oceans or buried in ancient Antarctic ice.

Now Jonathan Perkin, a  fresh-faced physicist at the University of Sheffield suggests that it might also be possible to listen for the sound that neutrinos make when they whizz through water. The thinkin is that an ultra high energy neutrino smashing into an atom rapidly raises the temperature of the water nearby producing an acoustic pulse which could be picked up by an off-the-shelf hydrophone.

Neat idea, except that Perkin goes on to to say that to have a realistic chance of picking up the sound of neutrinos you’d need a detector that is over a thousand cubic kilometres in size with over 100 hydrophones in each cubic kilometre. That’s big enough to be a nonstarter in most people’s books.

Where neutrino noise might turn out to be useful, however, is for filtering data from the big neutrino telescopes such as IceCube under the South Pole.

Pick up both the light and sound signatures of a neutrino hit and that’s pretty good evidence that it ain’t no false alarm. So the sound of neutrinos zipping past might turn out to be useful after all.

Ref: The Acoustic Detection of Ultra High Energy Neutrinos

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