arXiv subjects

Norikazu Kinoshita

Publications and source records attributed to Norikazu Kinoshita.

5 recordsLinked to original sources

arXiv2026

Analysis of the energy and angular distributions of photoneutrons from natPb, 197Au, natSn, natCu, natFe, and natTi using resonance direct theory

Photoneutron double-differential cross sections in the giant dipole resonance (GDR) region were calculated to investigate the underlying nuclear reaction mechanisms, with particular emphasis on the role of the direct process. Contributions from direct, pre-equilibrium, and compound processes were all taken into account. Wilkinson's resonance direct (RD) theory, based on the independent particle model, was applied to describe high-energy neutron emission from the direct process. The angular distribution of neutrons emitted via the RD mechanism was formulated using the Agodi and Courant formalism, which was incorporated into the RD framework. Neutron emission from the pre-equilibrium and compound processes was calculated using the two-component exciton model and the Hauser-Feshbach formalism, respectively. The calculated results were compared with experimental data obtained at NewSUBARU using 16.6-MeV quasi-monochromatic linearly-polarized photon beams. Good agreement between calculations and measurements was observed for Pb, Au, and Sn, confirming the validity of the proposed model. Furthermore, the angular anisotropies of photoneutrons emitted from these elements were investigated, revealing considerable contributions from the RD process at high neutron energies. This study provides a deeper understanding of photoneutron emission mechanisms in the GDR energy region.

nucl-th↗

arXiv2024

Proton induced reaction on $^{108}$Cd for astrophysical p-process studies

The proton capture cross-section of the least abundant proton-rich stable isotope of cadmium, $^{108}$Cd (abundance 0.89\%), has been measured near the Gamow window corresponding to a temperature range of 3-4 GK. The measurement of the $^{108}$Cd(p,$γ$)$^{109}$In reaction was carried out using the activation technique. The cross-section at the lowest energy point of 3T$_9$, E$_p$$^{lab}$= 2.28 MeV, has been reported for the first time. The astrophysical S-factor was measured in the energy range relevant to the astrophysical p-process, between E$_p$$^{cm}$= 2.29 and 6.79 MeV. The experimental results have been compared with theoretical predictions of Hauser-Feshbach statistical model calculations using TALYS-1.96. A calculated proton-optical potential was implemented to achieve better fitting, with different combinations of available nuclear level densities (NLDs) and $γ$-ray strength functions in TALYS-1.96. The calculations provided satisfactory agreement with the experimental results. The reaction rate was calculated using the calculated potential in TALYS-1.96 and compared with the values provided in the REACLIB database.

nucl-ex↗

arXiv2016

The Link Between the Local Bubble and Radioisotopic Signatures on Earth

Traces of 2-3 Myr old 60Fe were recently discovered in a manganese crust and in lunar samples. We have found that this signal is extended in time and is present in globally distributed deep-sea archives. A second 6.5-8.7 Myr old signature was revealed in a manganese crust. The existence of the Local Bubble hints to a recent nearby supernova-activity starting 13 Myr ago. With analytical and numerical models generating the Local Bubble, we explain the younger 60Fe-signature and thus link the evolution of the solar neighborhood to terrestrial anomalies.

astro-ph.EP↗

arXiv2012

Shielding experiments by the JASMIN collaboration at Fermilab (II) - Radioactivity measurement induced by secondary particles from the anti-proton production target

The JASMIN Collaboration has performed an experiment to conduct measurements of nuclear reaction rates around the anti-proton production (Pbar) target at the Fermi National Accelerator Laboratory (FNAL). At the Pbar target station, the target, consisting an Inconel 600 cylinder, was irradiated by a 120 GeV/c proton beam from the FNAL Main Injector. The beam intensity was 3.6 x 10**12 protons per second. Samples of Al, Nb, Cu, and Au were placed near the target to investigate the spatial and energy distribution of secondary particles emitted from it. After irradiation, the induced activities of the samples were measured by studying their gamma ray spectra using HPGe detectors. The production rates of 30 nuclides induced in Al, Nb, Cu, Au samples were obtained. These rates increase for samples placed in a forward (small angle) position relative to the target. The angular dependence of these reaction rates becomes larger for increasing threshold energy. These experimental results are compared with Monte Carlo calculations. The calculated results generally agree with the experimental results to within a factor of 2 to 3.

physics.acc-ph↗

arXiv2012

JASMIN: Japanese-American study of muon interactions and neutron detection

Experimental studies of shielding and radiation effects at Fermi National Accelerator Laboratory (FNAL) have been carried out under collaboration between FNAL and Japan, aiming at benchmarking of simulation codes and study of irradiation effects for upgrade and design of new high-energy accelerator facilities. The purposes of this collaboration are (1) acquisition of shielding data in a proton beam energy domain above 100 GeV; (2) further evaluation of predictive accuracy of the PHITS and MARS codes; (3) modification of physics models and data in these codes if needed; (4) establishment of irradiation field for radiation effect tests; and (5) development of a code module for improved description of radiation effects. A series of experiments has been performed at the Pbar target station and NuMI facility, using irradiation of targets with 120 GeV protons for antiproton and neutrino production, as well as the M-test beam line (M-test) for measuring nuclear data and detector responses. Various nuclear and shielding data have been measured by activation methods with chemical separation techniques as well as by other detectors such as a Bonner ball counter. Analyses with the experimental data are in progress for benchmarking the PHITS and MARS15 codes. In this presentation recent activities and results are reviewed.

physics.acc-ph↗