Using this setup, the experiment aims to measure the neutrino oscillation parameters.
T2K consists of a neutrino beamline, producing an intense muon neutrino beam a near detector complex, containing the INGRID on-axis detector and ND280 off-axis detector and a far detector, Super-Kamiokande (Super-K). This result, and a comparison with the MC prediction, are shown in Sects. During the beam operation, measurements of the absolute muon yield were conducted using an emulsion detector. The stability of the beam direction and its intensity during T2K beam operation is discussed in Sect. In this section we also show the systematic error in the beam direction measurement, which was estimated using both the actual beam data and MC simulation. A method for reconstructing the profile of the muon beam with the muon monitor is described in Sect. Section 3 gives an overview of the components of the muon monitor.
In this paper, we first provide an overview of the T2K experiment, emphasizing the importance of a precise measurement of the muon beam direction in Sect. In addition, a direct muon flux measurement would strengthen the strategy to control the neutrino beam based on the muon beam monitoring. To accomplish this, it is highly important to evaluate the detector performance. As the muon monitor is the only detector which can monitor the beam spill-by-spill, our strategy is to monitor the muon beam direction with a precision of 0.3 mrad for every beam spill, in order to better control the neutrino beam for the neutrino oscillation measurement.
Thus, it is important to monitor the neutrino beam direction on a spill-by-spill basis with good precision. On the other hand, it requires stringent control of the neutrino beam direction. This method enables us to measure the oscillation parameters with high sensitivity. As we describe later, T2K utilizes the off-axis method whereby the central axis of the beam is intentionally shifted by 2.5 |$^\circ$| from the direction of the near and far detectors. In an accelerator-based long baseline neutrino experiment, control of the neutrino beam is one of the key items. The T2K muon monitor was installed to monitor the muon beam which is produced together with the neutrino beam from the decay of pions. The number of muon tracks was measured to be |$(4.06\pm 0.05\pm 0.10)\times 10^4$|cm |$^$| protons on target (p.o.t.) had been collected as of May 2013. In order to understand the muon beam properties, measurement of the absolute muon yield at the muon monitor was conducted with an emulsion detector. During beam operation, the proton beam has been controlled using measurements from the muon monitor and the direction of the neutrino beam has been tuned to within 0.3 mrad with respect to the designed beam-axis. The systematic error in the muon beam direction measurement was estimated, using data and MC simulation, to be 0.28 mrad. The T2K muon monitor was installed to measure the direction and stability of the muon beam which is produced in conjunction with the muon neutrino beam. The Tokai-to-Kamioka (T2K) neutrino experiment measures neutrino oscillations by using an almost pure muon neutrino beam produced at the J-PARC accelerator facility.