The Acoustic Detection of Ultra High Energy Neutrinos

Attempts have been made to parameterise the thermoacoustic emission of particle cascades induced by EeV neutrinos interacting in the sea. Understanding the characteristic radiation from such an event allows us to predict the pressure pulse observed by underwater acoustic sensors distributed in kilometre scale arrays. We find that detectors encompassing thousands of cubic kilometres are required, with a minimum of 100 hydrophones per kilometre cubed, in order to observe the flux of neutrinos predicted by the attenuation of ultra high energy cosmic rays on cosmic microwave background photons. The pressure threshold of such an array must be in the range 5-10 mPa and the said detector will have to operate for five years or more. Additionally a qualitative analysis of the first acoustic data recorded by the Rona hydrophone array off the north-west coast of Scotland is reported.