Acoustic detection of high energy neutrinos in sea water: status and prospects

Robert Lahmann,S Buitink,R Nahnhauer,J.R Hörandel,S De Jong,O Scholten,R Lahmann

doi:10.1051/epjconf/201713506001

Abstract

The acoustic neutrino detection technique is a promising approach for future large-scale detectors with the aim of measuring the small expected flux of neutrinos at energies in the EeV-range and above. The technique is based on the thermo-acoustic model, which implies that the energy deposition by a particle cascade - resulting from a neutrino interaction in a medium with suitable thermal and acoustic properties - leads to a local heating and a subsequent characteristic pressure pulse that propagates in the surrounding medium. Current or recent test setups for acoustic neutrino detection have either been add-ons to optical neutrino telescopes or have been using acoustic arrays built for other purposes, typically for military use. While these arrays have been too small to derive competitive limits on neutrino fluxes, they allowed for detailed studies of the experimental technique. With the advent of the research infrastructure KM3NeT in the Mediterranean Sea, new possibilities will arise for acoustic neutrino detection. In this article, results from the "first generation" of acoustic arrays will be summarized and implications for the future of acoustic neutrino detection will be discussed.

Highlights

Measuring acoustic pressure pulses in huge underwater acoustic arrays is a promising approach for the detection of ultra-high-energy (UHE, Eν 109 GeV) neutrinos
The technique is based on the thermo-acoustic model, which implies that the energy deposition by a particle cascade – resulting from a neutrino interaction in a medium with suitable thermal and acoustic properties – leads to a local heating and a subsequent characteristic pressure pulse that propagates in the surrounding medium
Current or recent test setups for acoustic neutrino detection have either been add-ons to optical neutrino telescopes or have been using acoustic arrays built for other purposes, typically for military use

Summary

Introduction

Measuring acoustic pressure pulses in huge underwater acoustic arrays is a promising approach for the detection of ultra-high-energy (UHE, Eν 109 GeV) neutrinos. These are expected to be produced in interactions of cosmic rays with the cosmic microwave background [1]. Main advantage of using sound for the detection of neutrino interactions, as opposed to Cherenkov light, lies in the much longer attenuation length of the former type of radiation – several kilometres for sound compared to several tens of meters for light in the respective frequency ranges of interest in sea water. Discussions on neutrino detection in fresh water and ice can be found in [7] and [8], respectively

Sound in water and acoustic neutrino detection

Results of the “first generation” of acoustic neutrino test setups

Conclusions and outlook