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Y. Yamanoi

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Papers by Y. Yamanoi

A superconducting spectrometer for the study of hypernuclei via (π, K+) reactions

Il Nuovo Cimento A, 1989

Summary A superconducting kaon spectrometer (INS-SKS) is under construction at Institute for Nuc... more Summary A superconducting kaon spectrometer (INS-SKS) is under construction at Institute for Nuclear Study, University of Tokyo. The spectrometer, with 1/1000 momentum resolution and 100 msr acceptance, has been designed for intensive study of hypernuclei via (π, K+) reactions. It is to be installed in a new experimental hall of the KEK 12 GeV proton synchrotron and is scheduled to be ready for experiments by the end of 1990.

Energy spectra and angular distribution of intermediate mass fragments emitted in reactions with Ep = 12 GeV (The first result of the KEK-12GeV-PS experiment; E288)

Nuclear Physics A, 1995

The latest results of the first nuclear multifragmentation experiment, E288 [1], at the KEK 12 Ge... more The latest results of the first nuclear multifragmentation experiment, E288 [1], at the KEK 12 GeV Proton Synchrotron (KEK-PS) are presented. The energy spectra of intermediate mass fragments (IMFs) were measured inclusively from 30 ° to 150 ° with 20 ° step in the lab. system. Coincidence measurements with one extra IMF emitted toward 90 ° direction in the opposite hemisphere were performed at the same time. Characteristic sideward flow of IMFs toward 70 ° direction was found with the usual isotropic component. This isotropic component was strongly suppressed in the coincidence measurement. These facts may indicate the formation of unusually shaped nuclear matter such as an expanding toroid.

Application of Bragg-curve counters to a target multifragmentation measurement

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1996

The T2K experiment

Nuclear Instruments & Methods in Physics Research Section A-Accelerators Spectrometers Detectors and Associated Equipment, 2011

The T2K experiment is a long-baseline neutrino oscillation experiment. Its main goal is to measur... more The T2K experiment is a long-baseline neutrino oscillation experiment. Its main goal is to measure the last unknown lepton sector mixing angle θ 13 by observing ν e appearance in a ν µ beam. It also aims to make a precision measurement of the known oscillation parameters, ∆m 2 23 and sin 2 2θ 23 , via ν µ disappearance studies. Other goals of the experiment include various neutrino cross section measurements and sterile neutrino searches. The experiment uses an intense proton beam generated by the J-PARC accelerator in Tokai, Japan, and is composed of a neutrino beamline, a near detector complex (ND280), and a far detector (Super-Kamiokande) located 295 km away from J-PARC. This paper provides a comprehensive review of the instrumentation aspect of the T2K experiment and a summary of the vital information for each subsystem.

Measurements of the T2K neutrino beam properties using the INGRID on-axis near detector

Nuclear Instruments & Methods in Physics Research Section A-Accelerators Spectrometers Detectors and Associated Equipment, 2012

Precise measurement of neutrino beam direction and intensity was achieved based on a new concept ... more Precise measurement of neutrino beam direction and intensity was achieved based on a new concept with modularized neutrino detectors. INGRID (Interactive Neutrino GRID) is an on-axis near detector for the T2K long baseline neutrino oscillation experiment. INGRID consists of 16 identical modules arranged in horizontal and vertical arrays around the beam center. The module has a sandwich structure of iron target plates and scintillator trackers. INGRID directly monitors the muon neutrino beam profile center and intensity using the number of observed neutrino events in each module. The neutrino beam direction is measured with accuracy better than 0.4 mrad from the measured profile center. The normalized event rate is measured with 4% precision.

Indication of Electron Neutrino Appearance from an Accelerator-Produced Off-Axis Muon Neutrino Beam

Physical Review Letters, 2011

The T2K experiment observes indications of ν µ → ν e appearance in data accumulated with 1.43 × 1... more The T2K experiment observes indications of ν µ → ν e appearance in data accumulated with 1.43 × 10 20 protons on target. Six events pass all selection criteria at the far detector. In a threeflavor neutrino oscillation scenario with |∆m 2 23 | = 2.4 × 10 -3 eV 2 , sin 2 2θ 23 = 1 and sin 2 2θ 13 = 0, the expected number of such events is 1.5±0.3(syst.). Under this hypothesis, the probability to observe six or more candidate events is 7×10 -3 , equivalent to 2.5σ significance. At 90% C.L., the data are consistent with 0.03(0.04)< sin 2 2θ 13 < 0.28(0.34) for δ CP = 0 and normal (inverted) hierarchy.

Measurement of neutrino oscillation by the K2K experiment

Physical Review D, 2006

We present measurements of νµ disappearance in K2K, the KEK to Kamioka long-baseline neutrino osc... more We present measurements of νµ disappearance in K2K, the KEK to Kamioka long-baseline neutrino oscillation experiment. One hundred and twelve beam-originated neutrino events are observed in the fiducial volume of Super-Kamiokande with an expectation of 158.1 +9.2 -8.6 events without oscillation. A distortion of the energy spectrum is also seen in 58 single-ring muon-like events with reconstructed energies. The probability that the observations are explained by the expectation for no neutrino oscillation is 0.0015% (4.3σ). In a two flavor oscillation scenario, the allowed ∆m 2 region at sin 2 2θ = 1 is between 1.9 and 3.5 × 10 -3 eV 2 at the 90 % C.L. with a best-fit value of 2.8 × 10 -3 eV 2 .

First muon-neutrino disappearance study with an off-axis beam

Physical Review D, 2012

We report a measurement of muon-neutrino disappearance in the T2K experiment. The 295-km muon-neu... more We report a measurement of muon-neutrino disappearance in the T2K experiment. The 295-km muon-neutrino beam from Tokai to Kamioka is the first implementation of the off-axis technique in a long-baseline neutrino oscillation experiment. With data corresponding to 1.43×10 20 protons on target, we observe 31 fully-contained single µ-like ring events in Super-Kamiokande, compared with an expectation of 104 ± 14 (syst) events without neutrino oscillations. The best-fit point for two-flavor νµ → ντ oscillations is sin 2 (2θ23) = 0.98 and |∆m 2 32 | = 2.65 × 10 -3 eV 2 . The boundary of the 90% confidence region includes the points (sin 2 (2θ23), |∆m 2 32 |) = (1.0, 3.1×10 -3 eV 2 ), (0.84, 2.65×10 -3 eV 2 ) and (1.0, 2.2×10 -3 eV 2 ).

Room-temperature immobilization of gold nanoparticles on Si(111) surface and their electron behaviour

Physical Chemistry Chemical Physics, 2008

Subthreshold antiproton production in pA, dA and αA reactions

Nuclear Physics A, 1998

ABSTRACT An enormous enhancement of antiproton production in deuteron- and α-induced reactions ha... more ABSTRACT An enormous enhancement of antiproton production in deuteron- and α-induced reactions has been observed in the subthreshold energy region between 2 and 5 GeV/nucleon. Antiprotons produced at 5.1° with a momentum range of between 1.0 and 2.5 GeV/c were measured by a beam-line spectrometer and identified by the time-of-flight method. The production cross sections in the deuteron- and α-induced reactions at an incident energy of 3.5 GeV/nucleon were 2 and 3 orders of magnitude larger than those in proton-induced reaction at the same energy. The enhancement in light-ion reactions could not be explained by the internal motion in the projectile and target nuclei. The target-mass dependence (C, Al, Cu and Pb) of the cross sections has also been studied. Further, the cross sections of π and K productions were measured.

Ionization chamber as a p, d and α beam intensity monitor

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1996

An ionization chamber was studied as a low-intensity beam monitor and worked well for p. d and (Y... more

Optical design of beam lines at the KEK-PS new experimental hall

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1995

Neutron beam line at the KEK 12-GeV PS

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1996

A tagged low-momentum kaon test-beam exposure with a 250L LAr TPC (J-PARC T32)

Journal of Physics: Conference Series, 2011

At the beginning of 2010, we presented at the J-PARC PAC an R&D program towards large (100 kton s... more At the beginning of 2010, we presented at the J-PARC PAC an R&D program towards large (100 kton scale) liquid argon TPCs, suitable to investigate, in conjunction with the J-PARC neutrino beam, the possibility of CP violation in the neutrino sector and to search for nucleon decay. As a first step we proposed a test experiment to identify and measure charged kaons, including their decays, in liquid argon. The detector, a 250L LAr TPC, is exposed to charged kaons, in a momentum range of 540 -800 MeV/c, in the K1.1BR beamline of the J-PARC slow extraction facility. This is especially important to estimate efficiency and background for nucleon decay searches in the charged kaon mode (p → νK + , etc.), where the kaon momentum is expected to be in the few hundred MeV/c range. A prototype setup has been exposed in the K1.1BR beamline in the fall of 2010. This paper describes the capabilities of the beamline, the construction and setting up of the detector prototype, along with some preliminary results.

GPS survey in long baseline neutrino-oscillation measurement

IEEE Transactions on Nuclear Science, 2004

... H. Noumi, M. Ieiri, Y. Katoh, E. Kusano, M. Minakawa, K. Nakamura, M. Sakuda, Y. Suzuki, M.Ta... more

Radiation-Resistant Magnets for the Neutrino Beamline at J-PARC

IEEE Transactions on Applied Superconductivity, 2012

The construction of the facility of the long baseline neutrino oscillation experiment using the J... more The construction of the facility of the long baseline neutrino oscillation experiment using the J-PARC&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s 50 GeV–0.75 MW proton beam was completed at the end of 2008. The number of radiation-resistant magnets we have prepared for the neutrino beamline of J-PARC were 15 with Polyimide resin Insulation(PI) against up to $10^{8}$ Gy, and 4 magnets with completely Mineral Insulation Cable

Radiation-Resistant Magnets for Hadron Experimental Hall of J-PARC

IEEE Transactions on Applied Superconductivity, 2010

More than 50 radiation-resistant electromagnets were constructed for the primary proton and the s... more More than 50 radiation-resistant electromagnets were constructed for the primary proton and the secondary particle beam lines of the Hadron Experimental Hall of Japan Proton Accelerator Research Complex (J-PARC). The main radiation-resistant technologies we employed were the Polyimide-resin Insulation conductor for magnets at the relatively low radiation exposure and the Mineral Insulation Cable for magnets at the seriously high radiation environment. The remote handling and maintenance scheme of radiation-resistant magnets for seriously high radiation environment was developed also based on the Chimney magnet technology and applied to magnets near the production target in the Hadron Hall. On January 27th 2009, the first proton beam was successfully introduced to the Hadron Hall from the main accelerator of J-PARC, i.e. 50 GeV Proton Synchrotron. On February 10th, the secondary particles were extracted to the experimental area of the Hadron Hall through the secondary particle beam line. No serious problem happened on magnets of both primary proton and the secondary particle beam lines until the end of the beam operation scheduled on February 26th.

Indirectly Cooled Radiation-Resistant Magnets for Hadron Target Station at J-PARC

IEEE Transactions on Applied Superconductivity, 2010

Shield Penetrating Water Cooled Bus Ducts for Radiation Resistant Magnets at J-PARC

IEEE Transactions on Applied Superconductivity, 2008

Development of radiation-resistant magnets for JHF project

IEEE Transactions on Appiled Superconductivity, 2002

As a part of the Japan Hadron Facility (JHF) Project, R&D on radiation-resistant magnets is being... more As a part of the Japan Hadron Facility (JHF) Project, R&D on radiation-resistant magnets is being carried out at the High Energy Accelerator Research Organization (KEK). JHF is the Japanese next-generation high-intensity accelerator project, which will provide 1-MW proton beams of 3 GeV and 50 GeV for various fields of science.