We conduct a search for the coherent Cherenkov radiation (from negative charge excess), induced by high energy cosmic-rays. As a medium for detecting Cherenkov radiation we use a 20 ton target of synthetic rock salt contained within a scintillation counter cosmic-ray hodoscope. Two parallel arrays of crossed bow tie antennas are put inside the salt bed and used as a detection tool. We also present preliminary results from beam tests of the approach done at SLAC.
High energy neutrino sources of astronomical origin are sought with data from the Super-Kamiokande-I detector. In this search, upward going muons with a minimum track length of 7m are used. During the first 5 years of operation, we have accumulated 2331 such events, of which 452 stopped in the detector and the rest passed through. This search, using the entire sample of upward going muon data from SK-I detector, revealed no statistically significant neutrino sources, setting new flux limits on astronomical neutrino sources.
We will report on the details of the ANITA instrument. This instrument is fundamentally a broadband antenna, which is arrayed and constructed in such a way as to be optimized for the detection and characterization of high-energy neutrino cascades. The requirement to maximize the detector view of the Antarctic ice fields implies low gain antennas yet the need for maximum sensitivity dictates using the highest gain possible. Since the Cherenkov signal increases quadratically at higher frequencies suggesting that the optimal selection is an antenna with constant gain as a function of frequency. The baseline design will be a linearly polarized log-periodic zigzag (LPZZ) antenna.