Implications of optical properties of ocean, lake, and ice for ultrahigh-energy neutrino detection

Observation of high-energy neutrinos using Cerenkov detectors embedded deep in Antarctic ice

Neutrinos are elementary particles that carry no electric charge and have little mass. As they interact only weakly with other particles, they can penetrate enormous amounts of matter, and therefore have the potential to directly convey astrophysical information from the edge of the Universe and from deep inside the most cataclysmic high-energy regions. The neutrino's great penetrating power, however, also makes this particle difficult to detect. Underground detectors have observed low-energy neutrinos from the Sun and a nearby supernova, as well as neutrinos generated in the Earth's atmosphere. But the very low fluxes of high-energy neutrinos from cosmic sources can be observed only by much larger, expandable detectors in, for example, deep water or ice. Here we report the detection of upwardly propagating atmospheric neutrinos by the ice-based Antarctic muon and neutrino detector array (AMANDA). These results establish a technology with which to build a kilometre-scale neutrino observatory necessary for astrophysical observations.

Reply to criticisms of the Pope and Fry paper on pure water absorption made in a comment by Quickenden et al

The measurements of the absorption spectrum of pure water in a paper by Pope and Fry [Appl. Opt. 36, 8710 (1997)] have been criticized by Quickenden et al. [Appl. Opt. 39, 2740 (2000)]. These criticisms are answered.