Acoustic noise in deep ice and environmental conditions at the South Pole

TL;DR

This study measures and analyzes the stable acoustic noise levels in deep Antarctic ice at the South Pole, providing essential data for designing future acoustic neutrino detectors.

Contribution

It presents the first detailed depth profile of acoustic noise in Antarctic ice and assesses its stability and magnitude over a year.

Findings

Noise level is stable over one year.

Absolute noise level is below 10 mPa at depths over 200 m.

Noise magnitude is comparable to ocean-based detection environments.

Abstract

To study the acoustic properties of the Antarctic ice the South Pole Acoustic Test Setup (SPATS) was installed in the upper part of drill holes for the IceCube neutrino observatory. An important parameter for the design of a future acoustic neutrino telescope is the acoustic background noise in the ice and its spatial and temporal variations. We study the absolute noise level depth profile from SPATS data and discuss systematic uncertainties. The measured noise is very stable over one year of data taking, and we estimate the absolute noise level to be < 10 mPa in the frequency range from 10 kHz to 50 kHz at depths below 200 m. This noise level is of the same order of magnitude as observed by ocean based acoustic neutrino detection projects in good weather conditions.