T2K ended its 2017-18 data-taking run on May 31, 2018, with a record power of 500 kW delivered by the J-PARC Main Ring accelerator. T2K has accumulated a total of 3.16×10^21 protons on target (POT) so far. Preliminary results from a subset of these data were presented at the XXVIII International Conference on Neutrino Physics and Astrophysics (Neutrino 2018) in Heidelberg, Germany, on June 4 2018. Scientific results from the full data set will be released in the summer 0f 2018.
The protons are produced by the J-PARC Main Ring synchrotron accelerator in Tokai on the east coast of Japan. The 30 GeV protons are directed onto a graphite target, producing charged pions and other secondary particles. These pions pass through three magnetic “horns,” which are able to preferentially focus either positively-charged or negatively-charged pions in the direction of T2K’s neutrino detectors. Positively charged pions quickly decay to produce muon neutrinos , while negatively charged pions decay to produce muon antineutrinos. This allows T2K to produce a beam composed mostly of muon neutrinos or muon antineutrinos by changing the direction of the magnetic horn current.
