Oxford University PressActa Medica Okayama2050-3911202042020Gamma-ray spectra from thermal neutron capture on gadolinium-155 and natural gadolinium043D02ENTomoyukiTanakaDepartment of Physics, Okayama UniversityKaitoHagiwaraDepartment of Physics, Okayama UniversityEnricoGazzolaUniversitá di Padova and INFN, Dipartimento di FisicaAjmiAliDepartment of Physics, Okayama UniversityIwaOuDepartment of Physics, Okayama UniversityTakashiSudoDepartment of Physics, Okayama UniversityPretam KumarDasDepartment of Physics, Okayama UniversityMandeep SinghReenDepartment of Physics, Okayama UniversityRohitDhirDepartment of Physics, Okayama UniversityYusukeKoshioDepartment of Physics, Okayama UniversityMakotoSakudaDepartment of Physics, Okayama UniversityAtsushiKimuraJapan Atomic Energy AgencyShojiNakamuraJapan Atomic Energy AgencyNobuyukiIwamotoJapan Atomic Energy AgencyHideoHaradaJapan Atomic Energy AgencyGianmariaCollazuolUniversitá di Padova and INFN, Dipartimento di FisicaSebastianLorenzInstitut für Physik, Johannes Gutenberg-Universität MainzMichaelWurmInstitut für Physik, Johannes Gutenberg-Universität MainzWilliamFocillonDépartement de Physique, École PolytechniqueMichelGoninDépartement de Physique, École PolytechniqueTakatomiYanoKamioka Observatory, ICRR, University of TokyoNatural gadolinium is widely used for its excellent thermal neutron capture cross section, because of its two major isotopes: Gd-155 and Gd-157. We measured the gamma-ray spectra produced from the thermal neutron capture on targets comprising a natural gadolinium film and enriched Gd-155 (in Gd2O3 powder) in the energy range from 0.11 MeV to 8.0 MeV, using the ANNRI germanium spectrometer at MLF, J-PARC. The freshly analyzed data of the Gd-155(n,gamma) reaction are used to improve our previously developed model (ANNRI-Gd model) for the Gd-157(n,gamma) reaction [K. Hagiwara et al. [ANNRI-Gd Collaboration], Prog. Theor. Exp. Phys. 2019, 023D01 (2019)], and its performance confirmed with the independent data from the Gd-nat(n,gamma) reaction. This article completes the development of an efficient Monte Carlo model required to simulate and analyze particle interactions involving the thermal neutron captures on gadolinium in any relevant future experiments.No potential conflict of interest relevant to this article was reported.Acta Medica Okayama94142005Observation of the acceleration of a single bunch by using the induction device in the kek proton synchrotronENKenTakayamaKunioKosekiKotaTorikaiAkiraTokuchiEijiNakamuraYoshioArakidaYoshitoShimosakiMasayoshiWakeTadaakiKounoKazuhikoHoriokaSusumuIgarashiTaikiIwashitaAtsushiKawasakiJun-ichiKishiroMakotoSakudaHikaruSatoMakotoShihoMasashiShirakataTsuyoshiSuenoTakeshiToyamaMasaoWatanabeIsaoYamane<p>A single rf bunch in the KEK proton synchrotron was accelerated with an induction acceleration method from the injection energy of 500 MeV to 5 GeV.</p>No potential conflict of interest relevant to this article was reported.Acta Medica Okayama7252005Electron- and neutrino-nucleus scattering in the impulse approximation regimeENOmarBenherNicolaFarinaHirokiNakamuraMakotoSakudaRyoichiSeki<p>A quantitative understanding of the weak nuclear response is a prerequisite for the analyses of neutrino experiments such as K2K and MiniBOONE, which measure energy and angle of the muons produced in neutrino-nucleus interactions in the energy range 0.5-3 GeV and reconstruct the incident neutrino energy to determine neutrino oscillations. In this paper we discuss theoretical calculations of electron- and neutrino-nucleus scattering, carried out within the impulse approximation scheme using realistic nuclear spectral functions. Comparison between electron scattering data and the calculated inclusive cross section of oxygen, at beam energies ranging between 700 and 1200 MeV, show that the Fermi gas model, widely used in the analysis of neutrino oscillation experiments, fails to provide a satisfactory description of the measured cross sections, and inclusion of nuclear dynamics is needed.</p>No potential conflict of interest relevant to this article was reported.Oxford University PressActa Medica Okayama2050-391122019Gamma-ray spectrum from thermal neutron capture on gadolinium-157023D01ENKaitoHagiwaraDepartment of Physics, Okayama UniversityTakatomiYanoInstitute for Cosmic Ray Research, University of TokyoTomoyukiTanakaDepartment of Physics, Okayama UniversityMandeep SinghReenDepartment of Physics, Okayama UniversityPretam KumarDasDepartment of Physics, Okayama UniversitySebastianLorenzDepartment of Physics, Okayama UniversityIwaOuDepartment of Physics, Okayama UniversityTakashiSudoDepartment of Physics, Okayama UniversityYoshiyukiYamadaDepartment of Physics, Okayama UniversityTakaakiMoriDepartment of Physics, Okayama UniversityTsubasaKayanoDepartment of Physics, Okayama UniversityRohitDhirDepartment of Physics, Okayama UniversityYusukeKoshioDepartment of Physics, Okayama UniversityMakotoSakudaDepartment of Physics, Okayama UniversityAtsushiKimuraJapan Atomic Energy AgencyShojiNakamuraJapan Atomic Energy AgencyNobuyukiIwamotoJapan Atomic Energy AgencyHideoHaradaJapan Atomic Energy AgencyMichaelWurmInstitut für Physik, Johannes Gutenberg-Universität MainzWilliamFocillonDépartement de Physique, École PolytechniqueMichelGoninDépartement de Physique, École PolytechniqueAjmiAliDepartment of Physics, Okayama UniversityGianmariaCollazuolUniversitá di Padova and INFN, Dipartimento di FisicaWe have measured the -ray energy spectrum from the thermal neutron capture, Gd, on an enriched Gd target (GdO) in the energy range from 0.11 MeV up to about 8 MeV. The target was placed inside the germanium spectrometer of the ANNRI detector at J-PARC and exposed to a neutron beam from the Japan Spallation Neutron Source (JSNS). Radioactive sources (Co, Cs, and Eu) and the Cl(,) reaction were used to determine the spectrometers detection efficiency for rays at energies from 0.3 to 8.5 MeV. Using a Geant4-based Monte Carlo simulation of the detector and based on our data, we have developed a model to describe the -ray spectrum from the thermal Gd(,) reaction. While we include the strength information of 15 prominent peaks above 5 MeV and associated peaks below 1.6 MeV from our data directly into the model, we rely on the theoretical inputs of nuclear level density and the photon strength function of Gd to describe the continuum -ray spectrum from the Gd(,) reaction. Our model combines these two components. The results of the comparison between the observed -ray spectra from the reaction and the model are reported in detail.No potential conflict of interest relevant to this article was reported.Oxford University PressActa Medica Okayama2050-3911202312023Detection of the 4.4-MeV gamma rays from 16O(ν, ν′)16O(12.97 MeV, 2−) with a water Cherenkov detector in supernova neutrino bursts 013D02ENMakotoSakudaPhysics Department, Okayama UniversityToshioSuzukiDepartment of Physics, College of Humanities and Sciences, Nihon UniversityMandeep SinghReenDepartment of Physics, Akal UniversityKen'IchiroNakazatoFaculty of Arts and Science, Kyushu UniversityHideyukiSuzukiDepartment of Physics, Faculty of Science and Technology, Tokyo University of ScienceWe first discuss and determine the isospin mixing of the two 2− states (12.53 MeV and 12.97 MeV) of the16O nucleus using inelastic electron scattering data. We then evaluate the cross section of 4.4-MeV γ rays produced in the neutrino neutral-current (NC) reaction 16O(ν, ν′)16O(12.97 MeV, 2−) in a water Cherenkov detector at a low energy, below 100 MeV. The detection of γ rays for Eγ > 5 MeV from the NC reaction 16O(ν, ν′)16O(Ex > 16 MeV, T = 1) with a water Cherenkov detector in supernova neutrino bursts has been proposed and discussed by several authors previously. In this article, we discuss a new NC reaction channel from 16O(12.97 MeV, 2−) producing a 4.4-MeV γ ray, the cross section of which is more robust and even larger at low energy (Eν < 25 MeV) than the NC cross section from 16O(Ex > 16 MeV, T = 1). We also evaluate the number of such events induced by neutrinos from supernova explosion which can be observed by the Super-Kamiokande, an Earth-based 32-kton water Cherenkov detector.No potential conflict of interest relevant to this article was reported.Oxford University PressActa Medica Okayama2050-3911202362023Angular correlation of the two gamma rays produced in the thermal neutron capture on gadolinium-155 and gadolinium-157063H01ENPierreGouxDepartment of Physics, Okayama UniversityFranzGlessgenDepartment of Physics, Okayama UniversityEnricoGazzolaDepartment of Physics, Okayama UniversityMandeep SinghReenDepartment of Physics, Okayama UniversityWilliamFocillonDépartement de Physique, École Polytechnique, IN2P3/CNRSMichelGoninDépartement de Physique, École Polytechnique, IN2P3/CNRSTomoyukiTanakaDepartment of Physics, Okayama UniversityKaitoHagiwaraDepartment of Physics, Okayama UniversityAjmiAliDepartment of Physics, Okayama UniversityTakashiSudoDepartment of Physics, Okayama UniversityYusukeKoshioDepartment of Physics, Okayama UniversityMakotoSakudaDepartment of Physics, Okayama UniversityGianmariaCollazuolINFN Sezione di Padova and Università di Padova, Dipartimento di FisicaAtsushiKimuraJapan Atomic Energy AgencyShojiNakamuraJapan Atomic Energy AgencyNobuyukiIwamotoJapan Atomic Energy AgencyHideoHaradaJapan Atomic Energy AgencyMichaelWurmInstitut für Physik, Johannes Gutenberg-Universität MainzThe ANNRI-Gd collaboration studied in detail the single gamma-ray spectrum produced from the thermal neutron capture on Gd-155 and Gd-157 in our previous publications. Gadolinium targets were exposed to a neutron beam provided by the Japan Spallation Neutron Source (JSNS) in J-PARC, Japan. In the present analysis, one new additional coaxial germanium crystal was used in combination with the 14 germanium crystals in the cluster detectors to study the angular correlation of the two gamma rays emitted in the same neutron capture. We present for the first time angular correlation functions for two gamma rays produced during the electromagnetic cascade transitions in the (n, gamma) reactions on Gd-155 and Gd-157. As expected, we observe mild angular correlations for the strong, but rare transitions from the resonance state to the two energy levels of known spin-parities. Contrariwise, we observe negligibly small angular correlations for arbitrary pairs of two gamma rays produced in the majority of cascade transitions from the resonance state to the dense continuum states.No potential conflict of interest relevant to this article was reported.