Image credit: Kamioka Observatory, ICRR (Institute for Cosmic Ray Research), the University of Tokyo and the T2K collaboration.).
The international Tokai-to-Kamioka (T2K) collaboration announced the first detection of a long-distance neutrino in the Super-Kamiokande detector on 24 February. The neutrino had travelled 295 km under the Earth’s surface from the beamline at the Japan Proton Accelerator Research Complex (J-PARC) in Tokai, north of Tokyo, to the gigantic Super-Kamiokande underground detector in an old mine near the west coast of Japan.
The T2K experiment uses a high-intensity proton beam at J-PARC in Tokai to generate neutrinos that travel to the 50 kt water Cherenkov detector, Super-Kamiokande. The experiment follows in the footsteps of KEK-to-Kamioka (K2K), which generated muon neutrinos at the 12 GeV proton synchrotron at KEK. With the beam generated at the J-PARC facility, T2K will have a muon-neutrino beam 100 times more intense than in K2K.
The experiment has been built to make high-precision measurements of known neutrino oscillations, and to look for the so-far unobserved type of oscillation that would cause a small fraction of the muon-neutrinos produced at J-PARC to become electron-neutrinos by the time they reach Super-Kamiokande.
