Abstract
The detection of acoustic signals from ultra-high energy neutrino interactions is a promising method to measure the flux of cosmogenic neutrinos expected on Earth. The energy threshold for this process depends strongly on the absolute noise level in the target material. The South Pole Acoustic Test Setup (SPATS), deployed in the upper part of four boreholes of the IceCube Neutrino Observatory, has monitored the noise in Antarctic ice at the geographic South Pole for more than two years down to 500 m depth. The noise is very stable and Gaussian distributed. Lacking an in situ calibration up to now, laboratory measurements have been used to estimate the absolute noise level in the 10-50 kHz frequency range to be smaller than 20 mPa. Using a threshold trigger, sensors of the South Pole Acoustic Test Setup registered acoustic events in the IceCube detector volume and its vicinity. Acoustic signals from refreezing IceCube holes and from anthropogenic sources have been used to test the localization of acoustic events. An upper limit on the neutrino flux at energies Eν > 1011 GeV is derived from acoustic data taken over eight months.
| Original language | English |
|---|---|
| Pages (from-to) | 312-324 |
| Number of pages | 13 |
| Journal | Astroparticle Physics |
| Volume | 35 |
| Issue number | 6 |
| DOIs | |
| State | Published - Jan 2012 |
| Externally published | Yes |
Funding
We acknowledge the support from the following agencies: US National Science Foundation-Office of Polar Programs , US National Science Foundation-Physics Division , University of Wisconsin Alumni Research Foundation , the Grid Laboratory Of Wisconsin (GLOW) grid infrastructure at the University of Wisconsin – Madison, the Open Science Grid (OSG) grid infrastructure; US Department of Energy , and National Energy Research Scientific Computing Center , the Louisiana Optical Network Initiative (LONI) grid computing resources; National Science and Engineering Research Council of Canada ; Swedish Research Council , Swedish Polar Research Secretariat , Swedish National Infrastructure for Computing (SNIC) , and Knut and Alice Wallenberg Foundation, Sweden ; German Ministry for Education and Research (BMBF) , Deutsche Forschungsgemeinschaft (DFG) , Research Department of Plasmas with Complex Interactions (Bochum), Germany ; Fund for Scientific Research (FNRS-FWO) , FWO Odysseus programme , Flanders Institute to encourage scientific and technological research in industry (IWT), Belgian Federal Science Policy Office (Belspo) ; University of Oxford, United Kingdom ; Marsden Fund, New Zealand ; Japan Society for Promotion of Science (JSPS) ; the Swiss National Science Foundation (SNSF), Switzerland ; A. Groß acknowledges support by the EU Marie Curie OIF Program; J.P. Rodrigues acknowledges support by the Capes Foundation, Ministry of Education of Brazil .
Keywords
- Absolute noise level
- Acoustic neutrino detection
- Neutrino flux limit