arXiv subjects

Kunio Inoue

Publications and source records attributed to Kunio Inoue.

6 recordsLinked to original sources

arXiv2026

Towards imaging Earth's large-scale structures by directional geoneutrino detection with Ocean Bottom Detector

Geoneutrinos, electron antineutrinos produced by radioactive decays of heat-producing elements (HPEs) within the Earth, provide unique insights into Earth's interior and heat budget since their first detection in 2005 by KamLAND. Conventional geoneutrino detectors currently provide integrated global information and lack the capability to spatially resolve structures deep within the Earth. Here, we evaluate the ability of angular-sensitive geoneutrino detectors to distinguish between homogeneous and heterogeneous mantle models, focusing on Large Low Shear Velocity Provinces (LLSVPs). Our results show that LLSVPs enriched in Th and U yield a distinct flux of geoneutrinos with distinctive angular patterns. An oceanic site above the Pacific LLSVP is considered a particularly favorable detector location. The Ocean Bottom Detector (OBD) project aims to leverage this spatial resolving advantage by deploying a kiloton-scale liquid scintillator detector directly on the ocean floor, enabling unprecedented sensitivity for mantle geoneutrino detection. These findings demonstrate the critical role of combining geophysical and geochemical data to guide detector site selection, ultimately improving constraints on Earth's internal heat and the HPE distribution.

physics.geo-ph↗

arXiv2024

Combined Pre-Supernova Alert System with Kamland and Super-Kamiokande

Preceding a core-collapse supernova, various processes produce an increasing amount of neutrinos of all flavors characterized by mounting energies from the interior of massive stars. Among them, the electron antineutrinos are potentially detectable by terrestrial neutrino experiments such as KamLAND and Super-Kamiokande via inverse beta decay interactions. Once these pre-supernova neutrinos are observed, an early warning of the upcoming core-collapse supernova can be provided. In light of this, KamLAND and Super-Kamiokande, both located in the Kamioka mine in Japan, have been monitoring pre-supernova neutrinos since 2015 and 2021, respectively. Recently, we performed a joint study between KamLAND and Super-Kamiokande on pre-supernova neutrino detection. A pre-supernova alert system combining the KamLAND detector and the Super-Kamiokande detector was developed and put into operation, which can provide a supernova alert to the astrophysics community. Fully leveraging the complementary properties of these two detectors, the combined alert is expected to resolve a pre-supernova neutrino signal from a 15 M$_{\odot}$ star within 510 pc of the Earth, at a significance level corresponding to a false alarm rate of no more than 1 per century. For a Betelgeuse-like model with optimistic parameters, it can provide early warnings up to 12 hours in advance.

hep-ex↗

arXiv2021

Status and Perspectives of Neutrino Physics

This review demonstrates the unique role of the neutrino by discussing in detail the physics of and with neutrinos. We deal with neutrino sources, neutrino oscillations, absolute masses, interactions, the possible existence of sterile neutrinos, and theoretical implications. In addition, synergies of neutrino physics with other research fields are found, and requirements to continue successful neutrino physics in the future, in terms of technological developments and adequate infrastructures, are stressed.

hep-ph↗

arXiv2021

Geoneutrinos and geoscience: an intriguing joint-venture

The review is conceived to help the reader to interpret present geoneutrino results in the framework of Earth's energetics and composition. Starting from the comprehension of antineutrino production, propagation, and detection, the status of the geoneutrino field is presented through the description of the experimental and technological features of the Borexino and KamLAND ongoing experiments. The current understanding of the energetical, geophysical and geochemical traits of our planet is examined in a critical analysis of the currently available models. By combining theoretical models and experimental results, the mantle geoneutrino signal extracted from the results of the two experiments demonstrates the effectiveness in investigating deep earth radioactivity through geoneutrinos from different sites. The obtained results are discussed and framed in the puzzle of the diverse classes of formulated Bulk Silicate Earth models, analyzing their implications on planetary heat budget and composition. As a final remark, we present the engaging technological challenges and the future experiments envisaged for the next decade in the geoneutrino field.

physics.geo-ph↗

arXiv2016

High purity NaI(Tl) scintillator to search for dark matter

A high purity and large volume NaI(Tl) scintillator was developed to search for cosmic dark matter. The required densities of radioactive impurities (RIs) such as U-chain, Th-chain are less than a few ppt to establish high sensitivity to dark matter. The impurity of RIs were effectively reduced by selecting raw materials of crucible and by performing chemical reduction of lead ion in NaI raw powder. The impurity of $^{226}$Ra was reduced less than 100 $μ$Bq/kg in NaI(Tl) crystal. It should be remarked that the impurity of $^{210}$Pb, which is difficult to reduce, is effectively reduced by chemical processing of NaI raw powder down to less than 30 $μ$Bq/kg. The expected sensitivity to cosmic dark matter by using 250 kg of the high purity and large volume NaI(Tl) scintillator (PICO-LON; Pure Inorganic Crystal Observatory for LOw-background Neutr(al)ino) is 7$\times$10$^{-45}$ cm$^{2}$ for 50 GeV$/c^{2}$ WIMPs.

astro-ph.IM↗

arXiv2006

Neutrino Physics around MeV Energies

We present a brief informative overview of a broad ranges of subjects, the solar, the reactor, the geo and the supernova neutrinos (but without excluding possible biases), the topics which consist of the session ``Neutrino Physics around MeV Energies'' in NOW2006. Contrary to the naive expectation, the field is found to be very active in improving the performance of existing detectors, and in preparation for the development coming in the near future. The former includes excellent performance of SNO 3He detector, successful reconstruction of SK III, and KamLAND's new ``4pi'' calibration. The next data release from these experiments will be very exciting. The latter includes effort for lowering threshold in SK III, KamLAND's purification by which geo-neutrino observation becomes much cleaner, and the forthcoming 7Be neutrino measurement by BOREXINO and KamLAND. Possible detection of relic supernova neutrinos and non-zero effect of theta_{13} would bring us great excitement. Furthermore, improved new measurement of heavy element abundance in the solar atmosphere resulted in a solar model with much lower CNO νflux and with disagreement with helioseismology, thereby bringing us a new solar puzzle.

hep-ph↗