Acoustic resonant sensor for ultra high energy neutrino detection

The characterization of the cosmogenic neutrino flux would give insights into cosmological source evolution, source spectra and composition at injection, through the partial recovery of the degraded information carried by the ultra high energy cosmic rays. A suitable technique for the detection of these ultra high energy neutrinos relies on the observation of the coherent radio Cherenkov signature emitted by the interaction vertex shower. The detection of the concomitant acoustic pulse is further desirable in order to unambiguously demonstrate the origin of the radiation. Therefore, R&D activities around the design and construction of an acoustic sensor adequate for the detection of neutrino-induced acoustic pulses in ice, coincident with radio Cherenkov signals, down to an energy threshold of about Eν ≈ 1018 eV, were undertaken. The description of this new digital multi-channel sensor and its performance are presented in this paper. Moreover, the utilization of this sensor as a tool of choice for determining very low environmental acoustic noise levels is discussed.