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We report the direct measurement of the 7 Be solar neutrino signal rate performed with the Borexino detector at the Laboratori Nazionali del Gran Sasso. The interaction rate of the 0.862 MeV 7 Be neutrinos is 49±3stat±4syst counts/(day·100 ton). The hypothesis of no oscillation for 7 Be solar neutrinos is inconsistent with our measurement at the 4σ C.L.. Our result is the first direct measurement of the survival probability for solar νe in the transition region between matter-enhanced and vacuum-driven oscillations. The measurement improves the experimental determination of the flux of 7 Be, pp, and CNO solar νe, and the limit on the magnetic moment of neutrinos.PACS numbers: 13.35. Hb, 14.60.St, 26.65.+t, 95.55.Vj, 29.40.Mc Neutrino oscillations [1] are the established mechanism to explain the solar neutrino problem, which originated from observations in radiochemical experiments with a sub-MeV threshold [2,3] and from real time observation of high energy neutrinos [4,5]. Neutrino oscillations were also observed in atmospheric neutrinos [4] and have been confirmed with observation of reactorν e [6]. Borexino is the first experiment to report a real-time observation arXiv:0805.3843v2 [astro-ph]

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The international Muon Ionization Cooling Experiment (MICE), which is under construction at the Rutherford Appleton Laboratory (RAL), will demonstrate the principle of ionization cooling as a technique for the reduction of the phase-space volume occupied by a muon beam. Ionization cooling channels are required for the Neutrino Factory and the Muon Collider. MICE will evaluate in detail the performance of a single lattice cell of the Feasibility Study 2 cooling channel. The MICE Muon Beam has been constructed at the ISIS synchrotron at RAL, and in MICE Step I, it has been characterized using the MICE beam-instrumentation system. In this paper, the MICE Muon Beam and beam-line instrumentation are described. The muon rate is presented as a function of the beam loss generated by the MICE target dipping into the ISIS proton beam. For a 1 V signal from the ISIS beam-loss monitors downstream of our target we obtain a 30 KHz instantaneous muon rate, with a neglible pion contamination in the beam.