Acoustic sensor development for ultra high energy neutrino detection

The GZK neutrino flux characterization would give insights into cosmological source evolution, source spectra and composition at injection from the partial recovery of the degraded information carried by the ultra high energy cosmic rays. The flux is expected to be at levels necessitating a much larger instrumented volume ($>$100 km$^3$) than those currently operating. First suggested by Askaryan, both radio and acoustic detection techniques could render this quest possible thanks to longer wave attenuation lengths (predicted to exceed a kilometer) allowing for a much sparser instrumentation compared to optical detection technique. We present the current acoustic R&D activities at our lab developing adapted devices, report on the obtained sensitivies and triangulation capabilities we obtained, and define some of the requirements for the construction of a full scale detector.