The SPATS Pinger project

The feasibility of acoustic neutrino detection in ice is currently being investigated with the South Pole Acoustic Test Setup (SPATS). It consists of 3 strings, each with 7 transmitters and 7 sensors, which were installed at the South Pole in 2007, at a depth between 80 and 400 m. An additional string will be added in the austral summer 2007-2008, with 7 acoustic stages between 140 and 500 m. The data collected so far have allowed us to evaluate the noise and to confirm the small expected refraction of the sound at the instrumented depths. To determine the attenuation length and for a more precise study of the sound speed in the Antarctic ice, a retrievable portable acoustic transmitter has been built in DESY during 2007. The modular design has allowed the test of several emitters. The most powerful one will be used at the South Pole in December 2007 before the deployment of IceCube optical strings. Going down and up in water-filled holes it will continuously emit acoustic pulses which will be recorded with SPATS in a synchronized time scheme. This will allow us to collect data for 10³ times as many baselines as provided by SPATS alone. Thanks to the usage of the same isotropic emitter, an in-situ calibration may be possible