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Kreinder, B.; Cox, I.*; Grzywacz, R.*; 西尾 勝久; 他24名*
Nuclear Instruments and Methods in Physics Research A, 1085, p.171298_1 - 171298_7, 2026/05
被引用回数：0 パーセンタイル：0.00(Instruments & Instrumentation)In recent experiments, inorganic scintillators have been used to study the decays of exotic nuclei, providing an alternative to silicon detectors and enabling measurements that were previously impossible. However, proper use of these materials requires us to understand and quantify the scintillation process, specifically in response to very heavy nuclei. In this work, we show a simplified method based on the models of Birks (1951) and Meyer and Murray (1962) to parametrize the light output of inorganic scintillators in response to beams of energetic heavy ions over a broad range of energies. We test the accuracy of our parametrization approach by calculating light output and quenching factors for various ions and comparing them with experimental data from Lutetium Yttrium Orthosilicate (LYSO:Ce), a common inorganic scintillator. The Meyer-Murray model suggests that, for sufficiently heavy ions at high energies, the majority of the light output is associated with the creation of delta electrons, which are induced by the passage of the beam through the material. These delta electrons dramatically impact the response of detection systems when subject to ions with velocities typical of beams in modern fragmentation facilities. To illustrate this, we also present a qualitative estimate of the effects of delta rays on overall light output using the Birks-Meyer-Murray parametrization. The approach presented herein will serve as a basic framework for further, more rigorous studies of scintillator response to heavy ions. This work is a crucial first step in planning future experiments where energetic exotic nuclei are interacting with scintillator detectors.
Lu-DOTATATE therapy in Japan宮司 典明*; 三輪 建太*; 佐藤 達彦; 他25名*
Radiological Physics and Technology, 19(1), p.165 - 175, 2026/03
This study evaluated inter-institutional variability in kidney dosimetry using common Lu-SPECT/CT datasets from the SNMMI Dosimetry Challenge. Ten Japanese centers calculated kidney volumes and absorbed doses with various organ- and voxel-based software. Manual VOI contouring caused large variability (CV up to 16.9%), reduced to 7.4% using common VOIs. Voxel-based dosimetry yielded higher doses but reduced variability, highlighting the need for algorithm standardization to ensure reliable Lu-DOTATATE kidney dosimetry in Japan.
RhZhang, J. Z.*; Chen, Z. Q.*; Qu, T.*; Wang, Y. K.*; Li, Z. H.*; Orlandi, R.; 他62名*
Physics Letters B, 873, p.140144_1 - 140144_9, 2026/02
被引用回数：0 パーセンタイル：0.00(Astronomy & Astrophysics)At the RIKEN, 
-delayed 
-ray spectroscopy studies were conducted on 
Rh and 
Rh, resulting in the world's first successful identification of a 1/2
isomer in these isotope, extending the energy difference between the 9/2
and 1/2 states up to neutron number 
=74. Comparison of the new results with state-of-the-art calculations suggests that triaxial deformation plays a significant role in the evolution of the energy difference, indicating a shape transition from axially symmetric to triaxial deformation within the Rh isotopic series. These findings provide new insights into the structure of neutron-rich nuclei in the atomic number 
region, elucidating the interplay between triaxial deformation and shell evolution.
Gu, Y.*; 吉川 貴史; Bisogni, V.*; 他12名*
Nature, 645(8082), p.900 - 905, 2025/09
被引用回数：4 パーセンタイル：82.19(Multidisciplinary Sciences)Controlling spin currents, i.e., the flow of spin angular momentum, in small magnetic devices is the principal objective of spin electronics, a main contender for future energy efficient information technologies. Surprisingly, a pure spin current has never been measured directly since the associated electric stray fields and/or shifts in the non-equilibrium spin-dependent distribution functions are too small for conventional experimental detection methods optimized for charge transport. Here we report that resonant inelastic X-ray scattering (RIXS) can bridge this gap by measuring the spin current carried by magnons - the quanta of the spin wave excitations of the magnetic order - in the presence of temperature gradients across a magnetic insulator. This is possible due to the sensitivity of the momentum- and energy-resolved RIXS intensity to minute changes in the magnon distribution under non-equilibrium conditions. We use the Boltzmann equation in the relaxation time approximation to extract transport parameters, such as the magnon lifetime at finite momentum, essential for the realization of magnon spintronics.
Fe; Extending the shears mechanism to the 
shell orbitalBasu, S.*; Mukherjee, G.*; 宇都野 穣; 他32名*
Physics Letters B, 868, p.139642_1 - 139642_5, 2025/09
被引用回数：1 パーセンタイル：59.26(Astronomy & Astrophysics)インドのVariable Energy Cyclotron CentreにてFeの高スピン励起状態を生成し、そこからの脱励起ガンマ線を観測した。3136keVの
状態の上に
までの
のバンドが存在し、その
値が大きいこともわかった。そこから磁気回転バンドの存在が確かめられた。殻をバレンス殻にとった殻模型計算を行った結果、この磁気回転バンドは出現しないことがわかり、そこから得られた磁気回転バンドは
軌道へ2個励起した状態が主であると推測された。
mesons at finite density using a transport approach in 12 GeV pA reactions市川 真也; Gubler, P.; 成木 恵; KEK-PS E325 Collaboration*; 他25名*
Progress of Theoretical and Experimental Physics (Internet), 2025(9), p.093D01_1 - 093D01_21, 2025/08
被引用回数：1 パーセンタイル：48.62(Physics, Multidisciplinary)The hadron spectrum at finite density is an important observable for exploring the origin of hadron masses. In the KEK-PS E325 experiment, the di-electron decays of mesons inside and outside nuclei were measured using 12 GeV pA reactions. In the previous analysis, a significant excess was observed on the low-mass side of the meson peak in the data for slow-moving mesons (
= 
/
1.25) with the Cu target, and in-medium vector meson spectral modification was verified. We newly employed the PHSD transport approach to take into account the time evolution of spatial density distribution of the target nuclei. Consistent with the previous analysis, a significant excess was observed in the present analysis as well. It was found that incorporating momentum dependence into the spectral modification leads to better agreement with the experimental results. For the slow-moving mesons with the Cu target, the newly obtained modification parameters are consistent with those from the previous analysis within the uncertainties.
In, Sn, and 
Te measured with the HiCARI -ray spectrometer at RIBF at RIKENAcosta, J.*; Jungclaus, A.*; Armstrong, M.*; G
rska, M.*; Parry, T.*; Orlandi, R.; 他29名*
Physical Review C, 111(6), p.064316_1 - 064316_12, 2025/06
被引用回数：0 パーセンタイル：0.00(Physics, Nuclear)From 2020 to 2021, as part of the HiCARI project, high-resolution in-beam -ray spectroscopy experiments were conducted at the Radioactive Isotope Beam Factory. Using a collaboratively constructed array of 12 composite Ge detector systems, excitation state half-lives through Doppler-shifted spectroscopy were measured to investigate various physical phenomena. Specifically, we analyzed the Doppler-shifted line shapes of specific spin transitions and decays in In, Sn, and Te, characterizing the array and establishing reliable analytical methods. The obtained half-lifes were compared with existing experimental results and theoretical calculations.
experiment using a 
Cf calibration sourceLee, D. H.*; 百々 拓; 羽賀 勝洋; 原田 正英; 長谷川 勝一; 春日井 好己; 木下 秀孝; 増田 志歩; 明午 伸一郎; 酒井 健二; et al.
Nuclear Instruments and Methods in Physics Research A, 1072, p.170216_1 - 170216_6, 2025/03
被引用回数：2 パーセンタイル：80.51(Instruments & Instrumentation)JSNS investigates short-baseline neutrino oscillations using a 24-meter baseline and a 17-tonne Gd-loaded liquid scintillator target. Accurate event-reconstruction algorithms are crucial for analyzing experimental data. The algorithms undergo meticulous validation through calibration with a Cf source. This paper outlines the methodology and evaluates the reconstruction performance, focusing on neutrino interactions up to approximately 50 MeV for sterile neutrino searches. Both Cf and Michel electron events are studied to evaluate reconstruction accuracy. The analysis concludes that the uncertainty of the fiducial volume, with an appropriate correction, is much less than the requirement of JSNS requirement (10%). Furthermore, the energy resolution is measured to be 3.3 
0.1% for the Michel electron endpoint and 4.3 0.1% for the n-Gd peak in the central region.
佐藤 哲也*; 松尾 衛; 他2名*
Physical Review Letters, 134(10), p.106702_1 - 106702_7, 2025/03
被引用回数：2 パーセンタイル：69.59(Physics, Multidisciplinary)We theoretically investigate nonequilibrium spin fluctuations in a ferromagnet induced by a light pulse.
excited state and shape coexistence in 
Kr through 
Kr(d,p)Kr reactionWalter, D.*; Smallcombe, J.; 他25名*
Physics Letters B, 862, p.139352_1 - 139352_6, 2025/03
被引用回数：0 パーセンタイル：0.00(Astronomy & Astrophysics)A measurement of the excitation spectrum of Kr via one-neutron transfer to the ground state of Kr using the Kr(d,p)Kr reaction at 8A MeV, observing the outgoing protons, performed with the IRIS facility at TRIUMF is reported. Two states in Kr, at 1.500.14 MeV and 2.200.14 MeV, were observed. An adiabatic-wave approximation analysis of the differential cross sections leads us to identify the lower energy state as being populated with neutron transfer to the 3 orbital. This leads to the first observation of the lowest excited state in Kr, hence signaling shape co-existence. Theoretical calculations performed within the in-medium similarity renormalization group framework are presented that also show the existence of a low-energy state, aligning qualitatively with the observation.
Sanfilippo, A.*; 安邊 啓明; 他27名*
Nature Communications (Internet), 16, p.2016_1 - 2016_11, 2025/02
被引用回数：6 パーセンタイル：94.35(Multidisciplinary Sciences)Mantle processes control plate tectonics and exert an influence on biogeochemical cycles. However, the proportion of the mantle accessible to sampling is minimal, and a significant portion of our knowledge is derived from xenoliths, orogenic peridotite massifs exposed on land, and abyssal peridotites. Sampling of in-situ sections of the mantle is extremely challenging because they are buried beneath a magmatic crust with its sedimentary cover. In this study, we report the lithological characteristics of two mantle sections from an embryonic, very young, (~3 Ma) oceanic basin drilled by the International Ocean Discovery Program (IODP) in the central Tyrrhenian Sea. In contrast to observations made in drilled mantle sections from Mid Ocean Ridges (MORs) and hyperextended passive margins such as those in Iberia and Newfoundland, our findings revealed an exceptionally heterogeneous and generally fertile mantle. This represents a snapshot of young oceanic basement in a continental rifting environment characterised by general igneous starvation. The lithological heterogeneity ranges from fertile lherzolites to depleted harzburgites and dunites, variably interlayered with pyroxenites. Plagioclase- and clinopyroxene-rich layers, hydrous potassic magmatic veins, and gabbroic intrusions in these peridotites indicate substantial mantle re-fertilization and delayed inception of magmatic crust. The diverse lithological recovery indicates that magma-poor rifts do not necessarily require a chemically depleted mantle, too refractory to melt. Instead, we propose that deep lithospheric processes such as mantle refertilisation and prolonged lithospheric thinning hinder melt focusing and the formation of a steady-state spreading centre.
Marzec, E.*; 百々 拓; 羽賀 勝洋; 原田 正英; 長谷川 勝一; 春日井 好己; 木下 秀孝; 増田 志歩; 明午 伸一郎; 酒井 健二; et al.
Physical Review Letters, 134(8), p.081801_1 - 081801_9, 2025/02
被引用回数：5 パーセンタイル：89.75(Physics, Multidisciplinary)We present the first measurement of the missing energy due to nuclear effects in monoenergetic, muon neutrino charged-current interactions on carbon, originating from 
decay at rest (
), performed with the J-PARC Sterile Neutrino Search at the J-PARC Spallation Neutron Source liquid scintillator based experiment. Toward characterizing the neutrino interaction, ostensibly 
or 
C 
N, we define the missing energy as the energy transferred to the nucleus (
) minus the kinetic energy of the outgoing proton(s), 
, and relate this to visible energy in the detector, ![$$E_m = E_{nu_{mu}} (235.5 MeV) - m_{mu}(105.7 MeV) + [m_n - m_p(1.3 MeV)] - E_{vis}$$](/search/images/ERCV41JAHUQEKX11LRXHKX11LRWXK5L3EAUDEMZVFY0SATLFKYUSALJANVPXWXDNOV4SQMJQGUXDOICNMVLCSIBLEBNW0X1OEAWSA1K5OAUDCLRTEBGWKVRJLUQC0ICFL33XM0LTPUSA.gif)
. The missing energy, which is naively expected to be zero in the absence of nuclear effects (e.g., nucleon separation energy, Fermi momenta, and final-state interactions), is uniquely sensitive to many aspects of the interaction, and has previously been inaccessible with neutrinos. The shape-only, differential cross section measurement reported, based on a 
pure double-coincidence kaon decay-at-rest signal (621 total events), provides detailed insight into neutrino-nucleus interactions, allowing even the nuclear orbital shell of the struck nucleon to be inferred. The measurement provides an important benchmark for models and event generators at hundreds of MeV neutrino energies, characterized by the difficult-to-model transition region between neutrino-nucleus and neutrino-nucleon scattering, and relevant for applications in nuclear physics, neutrino oscillation measurements, and Type-II supernova studies.
7/2 low-spin states in 
Fr populated in the electron capture of the 1/2 ground state of RaClisu, C.*; Andreyev, A. N.; Nita, C. R.*; 他42名*
Physical Review C, 110(6), p.064315_1 - 064315_15, 2024/12
被引用回数：2 パーセンタイル：46.59(Physics, Nuclear)A level scheme of Fr, following the EC/
decay of its parent, was constructed at CERN's ISOLDE Decay Station. The decay strength suggests direct population of low-spin (
=7/2) excited states. Analysis of -single and 
coincidences identified new -ray transitions and states up to 
3.6 MeV. Spins and parities of these levels, beyond the known (7/2) state, were assigned based on =126 isotone systematics and compared to shell-model calculations. A new isomer with a half-life of 26(3)~ns was also found.
meson mass through 
decays佐甲 博之; 市川 真也; 成木 恵; 坂口 貴男; 佐藤 進; 他12名*
Journal of Subatomic Particles and Cosmology (Internet), 1-2, p.100012_1 - 100012_7, 2024/11
Experimental evidence for the mass and the chiral condensate of hadrons is still poor. To challenge this situation we aim to measure meson mass inside the nucleus through decays in proton-nucleus collisions at J-PARC. In this presentation we will show the experimental proposal (E88), and the status of preparation.
Rochman, D.*; 湊 太志; 渡邉 友章; 他52名*
EPJ Nuclear Sciences & Technologies (Internet), 10, p.9_1 - 9_83, 2024/10
This paper summarized the efforts performed to understand decay heat estimation from existing spent nuclear fuel (SNF), under the auspices of the Working Party on Nuclear Criticality Safety (WPNCS) of the OECD Nuclear Energy Agency. Needs for precise estimations are related to safety, cost, and optimization of SNF handling, storage, and repository. The physical origins of decay heat (a more correct denomination would be decay power) are then introduced, to identify its main contributors (fission products and actinides) and time-dependent evolution. Due to limited absolute prediction capabilities, experimental information is crucial; measurement facilities and methods are then presented, highlighting both their relevance and our need for maintaining the unique current full-scale facility and developing new ones. The third part of this report is dedicated to the computational aspect of the decay heat estimation: calculation methods, codes, and validation. Different approaches and implementations currently exist for these three aspects, directly impacting our capabilities to predict decay heat and to inform decision-makers. Finally, recommendations from the expert community are proposed, potentially guiding future experimental and computational developments.
C
reaction at 1.8 GeV/
with the Superconducting Kaon spectrometer市川 裕大; 藤田 真奈美; 長谷川 勝一; 今井 憲一*; 七村 拓野; 成木 恵; 佐藤 進; 佐甲 博之; 田村 裕和; 谷田 聖; et al.
Progress of Theoretical and Experimental Physics (Internet), 2024(9), p.091D01_1 - 091D01_13, 2024/09
被引用回数：3 パーセンタイル：50.77(Physics, Multidisciplinary)We conducted a measurement of the inclusive missing-mass spectrum in the C
reaction at an incident beam momentum of 1.8 GeV/. This measurement was carried out utilizing the Superconducting Kaon Spectrometer (SKS) and the K1.8 beamline spectrometer at the Hadron Experimental Hall in J-PARC. Remarkably, our experimental setup yielded an exceptionaly good energy resolution of 8.2 MeV (FWHM), enabling us to observe significant enhancements in the vicinity of the 
Be threshold region. In order to estimate the spectrum information, we employed several fitting parameters assumptions. The best agreement with the spectrum shape was obtained with combining quasi-free (QF) component and two-Gaussian functions, with the experimental resolution 
being held constant. The peak positions were obtained to be 
(stat.) 
(syst.) MeV and 
(stat.) 
(syst.) MeV. Another model assumption, utilizing quasi-free (QF) and one Breit-Wigner function with 
(stat.) 
(syst.) MeV and 
(stat.) 
(syst.) MeV, also yielded a similar 
value.
長江 大輔*; 阿部 康志*; 山口 由高*; 洲嵜 ふみ; 他27名*
Physical Review C, 110(1), p.014310_1 - 014310_13, 2024/07
被引用回数：9 パーセンタイル：90.84(Physics, Nuclear)A dedicated isochronous storage ring, named the Rare-RI Ring, was constructed at the RI Beam Factory of RIKEN, aiming at precision mass measurements of nuclei located in uncharted territories of the nuclear chart. The Rare-RI Ring employs the isochronous mass spectrometry technique with the goal to achieve a relative mass precision of 10
within a measurement time of less than 1 ms. The performance of the facility was demonstrated through mass measurements of neutron-rich nuclei with well-known masses. Velocity or magnetic rigidity is measured for every particle prior to its injection into the ring, wherein its revolution time is accurately determined. The latter quantity is used to determine the mass of the particle, while the former one is needed for nonisochronicity corrections. Mass precisions on the order of 10
were achieved in the first commissioning, which demonstrates that the Rare-RI Ring is a powerful tool for mass spectrometry of short-lived nuclei.
Jung, H.*; 松村 大樹; 他12名*
ACS Energy Letters (Internet), 9(5), p.2162 - 2172, 2024/04
被引用回数：23 パーセンタイル：91.43(Chemistry, Physical)A strategic approach has been proposed for designing robust, high-performing oxygen evolution reaction (OER) catalysts tailored for saline water splitting. By employing a density functional theory (DFT)-based computational screening process, a set of promising dopants were identified from a range of 26 3d to 5d transition metals, with the aim of enhancing the activity and saline water resilience of the catalysts. The screening methodology was 3-fold, encompassing evaluations of OER energetics, chlorine evolution reaction (ClER) energetics, and chloride-corrosion energetics. The screening led to the selection of Sc as a promising dopant, which substantially elevated the performance of the NiFeOOH catalysts. This improvement was validated by an 87 mV decrease in OER overpotential at 100 mA/cm
and a 100 h stability test under 1 M KOH + 0.5 M NaCl conditions. This study contributes to the understanding of the alkaline ClER and chloride-corrosion mechanisms, providing insights into catalyst behavior under saline conditions.
丸山 遥香*; 齊藤 英治; 他2名*
AIP Advances (Internet), 14(3), p.035217_1 - 035217_8, 2024/03
被引用回数：0 パーセンタイル：0.00(Nanoscience & Nanotechnology)We developed a radio frequency discharge apparatus for He gas to investigate the spin states of metastable helium (He
) interacting with solid-state surfaces. Our apparatus consisted of a stainless steel vacuum chamber, in which a coil produced He by discharging introduced He gas. The spin states of the He were detected using optical pumping and probing techniques. The chamber was designed to accommodate various solid-state samples. We measured the He polarization produced at a dielectric prism surface by total internal reflection of the circularly polarized pumping light. Our apparatus can be used to investigate possible spin transfer from various solid surfaces to He atoms.
-rays from slow neutron-induced fission of 
U with STEFFWright, T.*; 原田 秀郎; 木村 敦; 他121名*
European Physical Journal A, 60(3), p.70_1 - 70_11, 2024/03
被引用回数：0 パーセンタイル：0.00(Physics, Nuclear)The average energy and multiplicity of prompt -rays from slow neutron-induced fission of U have been measured using the STEFF spectrometer at the neutron time-of-flight facility n_TOF. The individual responses from 11 NaI scintillators were corrected for multiple -ray interactions, prompt fission neutrons and background counts before being deconvolved to estimate the emitted spectrum of prompt fission -rays. The results give an average -ray energy 
of 1.71(5) MeV and multiplicity 
of 2.66(18) considering -rays emitted within the energy range from 0.8 to 6.8 MeV. The n_TOF data has a slightly larger and smaller than other recent measurements, however the product of the two is in agreement within the quoted uncertainties.
