T. Nakadaira

Detectors and flux instrumentation for future neutrino facilities

This report summarises the conclusions from the detector group of the International Scoping Study of a future Neutrino Factory and Super-Beam neutrino facility. The baseline detector options for each possible neutrino beam are defined as follows: 1. A very massive (Megaton) water Cherenkov detector is the baseline option for a sub-GeV Beta Beam and Super Beam facility. 2. There are a number of possibilities for either a Beta Beam or Super Beam (SB) medium energy facility between 1-5 GeV. These include a totally active scintillating detector (TASD), a liquid argon TPC or a water Cherenkov detector. 3. A 100 kton magnetized iron neutrino detector (MIND) is the baseline to detect the wrong sign muon final states (golden channel) at a high energy (20-50 GeV) neutrino factory from muon decay. A 10 kton hybrid neutrino magnetic emulsion cloud chamber detector for wrong sign tau detection (silver channel) is a possible complement to MIND, if one needs to resolve degeneracies that appear in the δ-θ13 parameter space.

Development of Multi-Pixel Photon Counters

The multipixel photon counter (MPPC) is a newly developed photodetector with an excellent photon counting capability. It also has many attractive features such as small size, high gain, low operation voltage and power consumption, and capability of operating in magnetic fields and in room temperature. The basic performance of samples has been measured. A gain of ~106 is achieved with a noise rate less than 500 kHz with 1 p.e. threshold, and cross-talk probability of less than 40% at room temperature. The photon detection efficiency for green light is twice or more that of the photomultiplier tubes. It is found that the basic performance of the MPPC is satisfactory for use in real experiments.

Performance of multi-pixel photon counters for the T2K near detectors

We have developed a Multi-Pixel Photon Counter (MPPC) for the neutrino detectors of T2K experiment. About 64,000 MPPCs have been produced and tested in about a year. In order to characterize a large number of MPPCs, we have developed a system that simultaneously measures 64 MPPCs with various bias voltage and temperature. The performance of MPPCs are found to satisfy the requirement of T2K experiment. In this paper, we present the performance of 17,686 MPPCs measured at Kyoto University.

Search for Proton Decay via

We have searched for proton decay via p→νK+ using Super-Kamiokande data from April 1996 to February 2013, 260 kiloton•year exposure in total. No evidence for this proton decay mode is found. A lower limit of the proton lifetime is set to τ/B(p→νK+)>5.9×1033 years at 90% confidence level.

p \rightarrow \nu K^{+}

Following success of a prototype R&D, construction of a superconducting magnet system for J-PARC neutrino beam line has been carried out since 2005. A new conceptual beam line with the superconducting combined function magnets demonstrated the successful beam transport to the neutrino production target.

using 260 kiloton

A superconducting magnet system for the J-PARC neutrino beam line has been under construction since 2004. The system consists of 14 doublet cryostats; each contains 2 combined function magnets (SCFM). The SCFM uses two single layer left/right asymmetric coils that produce a dipole field of 2.6 T and quadrupole of 19 T/m. The SCFMs had been developed by 2004, mass-produced since 2005, and completed by summer 2008. The system is being installed since Feb. 2008 till the end of 2008. The paper summarizes the system overview including cryogenics and safety peripheries. The paper also reports the production and installation status.

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A new experiemntal program to study hadron production in hadron-nucleus and nucleus-nucleus collisions at the CERN SPS has been recently proposed by the NA49-future collaboration. The physics goals of the program are: -Search for the critical point of strongly interacting matter and a study of the properties of the onset of deconfinemnt in nucleus-nucleus collisions, -Measurements of correlations, fluctuations and hadron spectra at high pT in proton-nucleus collisions needed as for better understanding of nucleus-nucleus results, -Measurements of hadron production in hadron-nucleus interactions needed for neutrino (T2K) and cosmic-ray (Pierre Auger Observatory and KASCADE) expriments. The physics of the nucleus-nucleus program is reviewed in this presentation.

year data of Super-Kamiokande

This report summarises the conclusions from the detector group of the International Scoping Study of a future Neutrino Factory and Super-Beam neutrino facility. The baseline detector options for each possible neutrino beam are defined as follows: 1. A very massive (Megaton) water Cherenkov detector is the baseline option for a sub-GeV Beta Beam and Super Beam facility. 2. There are a number of possibilities for either a Beta Beam or Super Beam (SB) medium energy facility between 1-5 GeV. These include a totally active scintillating detector (TASD), a liquid argon TPC or a water Cherenkov detector. 3. A 100 kton magnetized iron neutrino detector (MIND) is the baseline to detect the wrong sign muon final states (golden channel) at a high energy (20-50 GeV) neutrino factory from muon decay. A 10 kton hybrid neutrino magnetic emulsion cloud chamber detector for wrong sign tau detection (silver channel) is a possible complement to MIND, if one needs to resolve degeneracies that appear in the δ-θ13 parameter space.

Construction of Superconducting Magnet System for the J-PARC Neutrino Beam Line

We have developed a special 1.3 × 1.3 mm type MPPC (667 pixels with 50 × 50 μm2 each) with Hamamatsu Photonics for the Tokai to Kamioka (T2K) long baseline neutrino experiment. 60,000 MPPCs will be used in the T2K neutrino detectors, which will be the first time that MPPCs have been used on such a large scale. We tested 17,000 MPPCs for the T2K near detectors. We report on the basic performance of the MPPCs.

Status of Superconducting Magnet System for the J-PARC Neutrino Beam Line

Long baseline neutrino experiments are designed to complete the knowledge on 3-flavor neutrino mixing by measuring the flavor change of accelerator-produced neutrinos. The current status of the measurement of the neutrino mixing angles by running experiments are reviewed. The recent progress in the θ13 measurements is reported. The future plans which will search the CP violation in the neutrino sector are also discussed.