Progress on deep‐sea neutrino detection

For several summers, a group of physicists, astrophysicists and oceanographers interested in using the oceans to detect ultrahigh‐energy cosmic‐ray neutrinos have been meeting to exchange ideas. Their interest arises because clean seawater could provide the massive detector needed to observe low fluxes of weakly interacting, deeply penetrating neutrinos (PHYSICS TODAY, April 1976, page 18). The detector volume, about one cubic kilometer, located 5 km or so underwater, would avoid gross interference from ordinary cosmic rays. Organized as DUMAND (Deep Underseas Muon and Neutrino Detector), the group has been formulating the questions that would need to be answered in any feasibility study of the project. The most recent workshop took place 24 July–1 September at the Scripps Institution of Oceanography, La Jolla, with about 90 participants from the US, the Federal Republic of Germany, Japan and the Soviet Union.