Publications

Journal Articles

Study of the acoustic signature of UHE neutrino interactions in water and ice

Abstract:
The production of acoustic signals from the interactions of ultra-high energy (UHE) cosmic ray neutrinos in water and ice has been studied. A new computationally fast and efficient method of deriving the signal is presented. This method allows the implementation of up to date parameterisations of acoustic attenuation in sea water and ice that now includes the effects of complex attenuation, where appropriate. The methods presented here have been used to compute and study the properties of the acoustic signals which would be expected from such interactions. A matrix method of parameterising the signals, which includes the expected fluctuations, is also presented. These methods are used to generate the expected signals that would be detected in acoustic UHE neutrino telescopes.

S. Bevan et al. (ACORNE Collaboration)
Submitted to Nuclear Instruments and Methods A


The sensitivity of km3 hydrophone arrays to fluxes of ultra high energy neutrinos

Abstract:
The thermoacoustic emission from particle cascades induced by EeV neutrinos deep inelastic scattering in abyssal seawater has been parameterised. We discuss the ability of cubic kilometre hydrophone arrays to observe EeV neutrinos in terms of their pressure threshold, exposure, and hydrophone density.

J. Perkin and on behalf of the ACORNE Collaboration
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, March 2009


Hydrophone-based calibrator for seawater acoustic detection of UHE neutrinos

Abstract:
A point source acoustic calibrator for the simulation of the neutrino-generated bipolar signals in seawater is developed. This is achieved through hydrophone modelling using standard signal processing techniques. The method is experimentally confirmed for an omni-directional source.

Omar Veledar and for the ACORNE collaboration
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, March 2009


ARENA 2008 acoustic detection conference summary

Abstract:
The principle for detecting ultra-high energy neutrinos acoustically is briefly introduced. Current activities in this field are numerous and many have been reported at this conference. They include, e.g., the co-deployment of acoustic sensors in optical Cherenkov neutrino telescopes, the analysis of acoustic data from the existing hydrophone arrays for calibration and noise determination purposes, the design of bespoke acoustic sensors and the development of signal processing techniques. A digest of the status of current acoustic detection projects is presented. The work of the authors referenced in this text can be found elsewhere in these proceedings.

Lee F. Thompson
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, March 2009


Data analysis techniques for UHE acoustic astronomy

Abstract:
Using acoustic techniques, it is hoped that a new type of telescope can be developed to search for ultra high energy (UHE) neutrinos. Using an eight hydrophone array, ACORNE is investigating the practicality of such an acoustic telescope. This paper will report on the progress of this investigation, focusing on the data analysis techniques developed. The sensitivity of the Rona array will be presented, and a limit placed on the flux of UHE neutrinos.

Simon Bevan
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, March 2009


Acoustic detection of ultra-high-energy neutrinos

Abstract:
At ultra-high energies (>1018 eV) the Earth is opaque to neutrinos and detection techniques other than the optical Cherenkov technique must be pursued. Here the possibility of detecting neutrinos via their acoustic signature is discussed. The paper presents an overview of current worldwide activities in the acoustic detection field which includes recent results from test experimental set-ups, simulation work, sensitivity calculations and results from data taken at deep-water deployments.

Lee F. Thompson
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 588, Issues 1-2, 1 April 2008, Pages 155-161


Simulating the sensitivity of hypothetical km3 hydrophone arrays to fluxes of UHE neutrinos Modelling the effects of refraction

Abstract:
The velocity of sound in the sea is not a constant, hence sound rays are subject to refraction. The work described here, attempts to model the distortion of the acoustic "pancake", emitted when a neutrino with over a joule of energy, scatters in the sea. The detection of such events by hypothetical arrays of hydrophones, distributed over volumes of several cubic kilometres is discussed.

Jonathan Perkin (for the ACORNE collaboration)
Jonathan Perkin et al 2007 J. Phys.: Conf. Ser. 81 012021 (6pp)


Future Plans for the ACORNE Collaboration

Abstract:
A summary of the future plans for ACORNE collaboration are presented. Of particular note is the intended development of an acoustic calibrator to be deployed in the deep sea above the Rona hydrophone array. Crucial to this goal is work recently completed on the understanding of hydrophone response and the generation of bipolar acoustic signals; this work is presented in detail.

Lee F Thompson (on behalf of the ACORNE Collaboration)
Lee F Thompson et al 2007 J. Phys.: Conf. Ser. 81 012023 (5pp)


Simulation of ultra high energy neutrino induced showers in ice and water

Abstract:
The CORSIKA program, usually used to simulate extensive cosmic ray air showers, has been adapted to work in a water or ice medium. The adapted CORSIKA code was used to simulate hadronic showers produced by neutrino interactions. The simulated showers have been used to study the spatial distribution of the deposited energy in the showers. This allows a more precise determination of the acoustic signals produced by ultra high energy neutrinos than has been possible previously. Some properties of the acoustic signals generated by such showers are described.

S. Bevan et al. (ACORNE Collaboration)
Astroparticle Physics, Volume 28, Issue 3, November 2007, Pages 366-379


First Data from ACORNE and Signal Processing Techniques

Abstract:
This paper attempts to estimate the performance of the Rona naval acoustic hydrophone array which has been recently upgraded to act as a test bed for an EeV neutrino detector. Preliminary estimation of the array performance is presented together with some preliminary data analysis and reduction techniques.

Seán Danaher (for the ACORNE Collaboration)
Seán Danaher et al 2007 J. Phys.: Conf. Ser. 81 012011 (8pp)



Theses

The Acoustic Detection of Ultra High Energy Neutrinos

Abstract:
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.

J. Perkin (The University of Sheffield Apr 2007)


An Investigation into the Feasibility of Sea Water or Ice Based Acoustic UHE Neutrino Telescopes

Abstract:
Using acoustic techniques, it is hoped that a new type of telescope can be developed for ultra-high energy neutrinos. Using an 8 hydrophone array, ACORNE is investigating the practicality of such an acoustic telescope. This thesis will report on the progress of this investigation, focusing on data analysis ans event reconstruction, with the aim of reducing the acoustic background at Rona. The sensitivity of the Rona array will be presented, and a limit placed on the flux of UHE neutrinos. The feasibility of acoustic detection in ice is also investigated.

S. Bevan (University College London Oct 2008)