掲載種別：研究論文（学術雑誌）   出版者・発行元：Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms  

Silicon-insulated gate bipolar transistors (Si-IGBTs) are widely used for power control. In this study, we measured the energy deposited inside a commercial device with neutrons irradiation from 252Cf. We irradiated the device from the sealing and heat sink sides to evaluate the directional characteristics. A radiation simulation analysis was performed to understand the measurement results. The experiment and simulation showed that energy deposition in the device occurs through elastic scattering of neutrons and nuclear reactions. In particular, protons were generated by elastic scattering in the sealing material when the device was irradiated from the sealing side. Thus, the effect of neutrons on commercial Si-IGBTs is due to not only reactions inside the device but also secondary particles from the sealing material. When irradiated with high-energy neutrons, the knocked-out protons from sealing possibly cause single-event burnout (SEB). Therefore, the probability of SEB may depend on the direction of neutron incidence.

DOI： 10.1016/j.nimb.2024.165374

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： https://doi.org/10.1016/j.nima.2023.168984

リポジトリ公開URL： https://hdl.handle.net/2324/7174411

掲載種別：研究論文（学術雑誌）   出版者・発行元：Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment  

In recent years, particle discrimination methods based on digital waveform analysis techniques for neutron-transmutation-doped silicon (nTD-Si) detectors have become widely used for the identification of low-energy charged particles. Although the particle discrimination capability of this method has been well demonstrated for small incident angles, the particle discrimination performance may be affected by changes in the detector response when the detector is moved closer to the charged particle source and the incident position distribution and incident angle distribution to the detector become wide. In this study, we performed a beam test for particle discrimination in light-charged (Z≤2) particles using the digital waveform analysis method with a pad-type nTD-Si detector and investigated the dependence of the performance of the particle discrimination on the incident position and incident angle. As the incident angle increased, a decrease in the maximum current was observed, which was sufficient to affect the performance of the particle discrimination. This decrease can be expressed as a function of the penetration depth of the charged particles into the detector, which varies for each nuclide.

DOI： 10.1016/j.nima.2023.168984

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics  

γ emission probabilities from unbound states in 78,80Se, populated by a neutron-transfer reaction (d,p) on 77,79Se nuclei in inverse kinematics, were measured by directly detecting reaction residues. Assuming the spin distribution at the respective excitation energy of the unbound state, the cross-sections of the 79Se(n,γ)80Se reaction were evaluated using the γ emission probabilities. The surrogate-ratio method with the experimental γ emission probabilities of 78,80Se was also employed to deduce the cross-sections of 79Se(n,γ) reaction by incorporating the theoretical evaluations of the neutron-capture reaction on the isomeric state in 77Se. Our two cross-sections are in good agreement with existing nuclear data compilations for the neutron-capture reaction on 79Se. The presented method contributes to the body of existing knowledge by providing approaches for determining the neutron capture cross-sections of radioactive nuclei at various neutron energies.

DOI： 10.1016/j.physletb.2024.138470

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：Progress of Theoretical and Experimental Physics  

Abstract

The deuteron is a loosely bound system which can easily break up into its constituent proton and neutron whilst in the presence of Coulomb and nuclear fields. Previous experimental studies have shown that this breakup process has a significant impact on residual nucleus production from deuteron bombardment in the high energy range of 50 – 210 MeV/nucleon. However, there remains a lack of cross-section data at energies below 50 MeV/nucleon. The current study determined 93Zr + d reaction cross sections under inverse kinematics at approximately 28 MeV/nucleon using the BigRIPS separator, OEDO beamline, and SHARAQ spectrometer. Cross sections from this research were compared with previous measurements and theoretical calculations. The experimental results show a large enhancement of the production cross sections of residual nuclei, especially those produced from a small number of particle emissions, compared to the proton-induced reaction data at similar bombarding energy. The DEURACS calculation, which quantitatively takes deuteron-breakup effects into account, reproduces the data well. As a long-lived fission product, 93Zr remains a challenge for nuclear waste disposal and treatment. This study’s low-energy data may assist future consideration of nuclear-waste treatment facilities, where 93Zr + d may feasibly transmute the waste into short-lived/stable nuclei.

DOI： 10.1093/ptep/ptad139

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Progress of Theoretical and Experimental Physics  

We have measured the differential cross section and analyzing power for (p, 2p) reactions that lead to discrete states of residual nuclei at an incident energy of 197 MeV for five kinds of target nuclei, 12C, 16O, 40,48Ca, and 90Zr. The data are compared with distorted-wave impulse approximation calculations using two kinds of global optical potentials. The spectroscopic factors obtained from these calculations agree with those determined in (e, e′p) studies within 20%, except for one orbital of the 90Zr nucleus where the distortion effect is much greater than that for the other orbitals of 90Zr and for other target nuclei. We also observed a clear and visibly distinct j-dependence in the analyzing power.

DOI： 10.1093/ptep/ptad116

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms  

We have launched a new research project named “ONOKORO” to elucidate the formation mechanism of clusters in atomic nuclei. The project comprehensively investigates clustering phenomena in the medium-to-heavy mass region with inverse-kinematics cluster-knockout reactions at the intermediate energy facilities. The new detector array named “TOGAXSI” is under construction for this purpose. It measures scattering angles and the energies of deuterons, tritons, 3He, and α particles emitted at forward angles from the cluster-knockout reactions. It also measures the recoil protons emitted from the scattering events at large angles. High-angular and high-energy resolutions with wide solid angles are required to achieve a good cluster separation energy resolution and a reasonably high yield. The designed telescope consists of silicon trackers and GAGG:Ce calorimeters. This paper shows the required conditions and design concepts of TOGAXSI.

DOI： 10.1016/j.nimb.2023.05.054

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms  

The cluster-knockout reaction project, ONOKORO, has been launched to elucidate the formation mechanism of clusters in atomic nuclei. For the inverse-kinetics cluster-knockout reaction experiments, a new detector array is under development to measure energies and angles of light ions emitted in the reactions. The silicon tracker tracks the particles with good angular and energy-loss resolutions. A performance test of the silicon strip detectors with a thickness of 100μm and a strip width of 100μm was performed using prototype silicon detectors. The mono-energetic proton and α-particle beams were irradiated on the silicon detectors. The energy-loss spectra in silicon detectors showed a good signal-to-noise ratio. The threshold level for signal detection is seven sigma of noise level. Their dynamic ranges were optimized wide enough to detect charge number Z= 1 and Z= 2 ions emitted in the cluster-knockout reactions.

DOI： 10.1016/j.nimb.2023.05.055

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Nature  

Subjecting a physical system to extreme conditions is one of the means often used to obtain a better understanding and deeper insight into its organization and structure. In the case of the atomic nucleus, one such approach is to investigate isotopes that have very different neutron-to-proton (N/Z) ratios than in stable nuclei. Light, neutron-rich isotopes exhibit the most asymmetric N/Z ratios and those lying beyond the limits of binding, which undergo spontaneous neutron emission and exist only as very short-lived resonances (about 10−21s), provide the most stringent tests of modern nuclear-structure theories. Here we report on the first observation of 28O and 27O through their decay into 24O and four and three neutrons, respectively. The 28O nucleus is of particular interest as, with the Z = 8 and N = 20 magic numbers1,2, it is expected in the standard shell-model picture of nuclear structure to be one of a relatively small number of so-called ‘doubly magic’ nuclei. Both 27O and 28O were found to exist as narrow, low-lying resonances and their decay energies are compared here to the results of sophisticated theoretical modelling, including a large-scale shell-model calculation and a newly developed statistical approach. In both cases, the underlying nuclear interactions were derived from effective field theories of quantum chromodynamics. Finally, it is shown that the cross-section for the production of 28O from a 29F beam is consistent with it not exhibiting a closed N = 20 shell structure.

DOI： 10.1038/s41586-023-06352-6

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その他リンク： https://www.nature.com/articles/s41586-023-06352-6

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics  

Detailed γ-ray spectroscopy of the exotic neon isotope 28Ne has been performed for the first time using the one-neutron removal reaction from 29Ne on a liquid hydrogen target at 240 MeV/nucleon. Based on an analysis of parallel momentum distributions, a level scheme with spin-parity assignments has been constructed for 28Ne and the negative-parity states are identified for the first time. The measured partial cross sections and momentum distributions reveal a significant intruder p-wave strength providing evidence of the breakdown of the N=20 and N=28 shell gaps. Only a weak, possible f-wave strength was observed to bound final states. Large-scale shell-model calculations with different effective interactions do not reproduce the large p-wave and small f-wave strength observed experimentally, indicating an ongoing challenge for a complete theoretical description of the transition into the island of inversion along the Ne isotopic chain.

DOI： 10.1016/j.physletb.2023.138038

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その他リンク： https://www.sciencedirect.com/science/article/pii/S0370269323003726

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： https://doi.org/10.1051/epjconf/202328401041

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Physical Review C  

The nucleus Ne29 is situated at the border of the island of inversion. Despite significant efforts, no bound low-lying intruder f7/2 state, which would place Ne29 firmly inside the island of inversion, has yet been observed. Here, the first investigation of unbound states of Ne29 is reported. The states were populated in Ne30(p,pn) and Na30(p,2p) reactions at a beam energy of around 230 MeV/nucleon, and analyzed in terms of their resonance properties, partial cross sections, and momentum distributions. The momentum distributions are compared to calculations using the eikonal, direct reaction model, allowing ℓ assignments for the observed states. The lowest-lying resonance at an excitation energy of 1.48(4) MeV shows clear signs of a significant ℓ=3 component, giving first evidence for f7/2 single particle strength in Ne29. The excitation energies and strengths of the observed states are compared to shell-model calculations using the sdpf-u-mix interaction.

DOI： 10.1103/PhysRevC.105.034301

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記述言語：その他   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.nima.2020.164687

記述言語：その他   掲載種別：研究論文（学術雑誌）  

DOI： 10.1103/physrevlett.125.122501

記述言語：その他   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.nimb.2019.06.006

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： https://doi.org/10.1038/s42005-019-0165-1

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1093/ptep/ptz007

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1093/ptep/ptz028

記述言語：その他   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.nima.2018.10.153

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1093/ptep/pty138

開催年月日： 2024年3月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：近畿大学東大阪キャンパス（大阪府東大阪市）   国名：日本国  

開催年月日： 2023年12月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：理化学研究所 和光キャンパス（埼玉県和光市）   国名：日本国  

開催年月日： 2023年11月

記述言語：日本語   会議種別：シンポジウム・ワークショップ パネル（公募）  

開催地：東海村産業・情報プラザ「アイヴィル(iVil)」（茨城県東海村）   国名：日本国  

その他リンク： https://conference-indico.kek.jp/event/238/contributions/4752/

開催年月日： 2023年11月

記述言語：日本語   会議種別：シンポジウム・ワークショップ パネル（公募）  

開催地：東海村産業・情報プラザ「アイヴィル(iVil)」（茨城県東海村）   国名：日本国  

その他リンク： https://conference-indico.kek.jp/event/238/contributions/4749/

開催年月日： 2023年9月

記述言語：日本語   会議種別：シンポジウム・ワークショップ パネル（公募）  

開催地：東北大学青葉山キャンパス   国名：日本国  

開催年月日： 2022年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：茨城大学日立キャンパス   国名：日本国  

近年、半導体デバイスの微細化によりミューオン起因のソフトエラーが注目されている。負ミューオン原子核捕獲反応 (μNC) により発生する二次軽荷電粒子がソフトエラーの原因になることが指摘されている。そこで、我々はミューオン起因ソフトエラー発生率の評価に必要なμNCで生成する二次軽荷電粒子のエネルギースペクトルを実測するため、荷電粒子測定系の開発を行っている。本測定系では、荷電粒子のエネルギーごとに粒子識別方法の異なる２種類のテレスコープを用いる。低エネルギー粒子はnTD-Si検出器によって検出し、波形解析法により粒子識別を行う。また、高エネルギー粒子はSi検出器とCsIシンチレータにより検出し、ΔE-E法により粒子識別を行う。本講演では、九州大学タンデム加速器施設で行った測定系の動作テストについて報告する。

開催年月日： 2022年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：茨城大学日立キャンパス   国名：日本国  

九州大学加速器・ビーム応用科学センターのタンデム加速器施設においてnTD-Si検出器を用いた波形解析法による軽荷電粒子の弁別性能評価実験を行った。nTD-Si検出器に入射する軽荷電粒子の位置および入射角度を変えた測定を行い、それらが波形解析法による粒子弁別能に与える影響を評価した。本講演では、性能評価実験の詳細および解析結果について報告する。

開催年月日： 2022年7月

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

その他リンク： https://indico.frib.msu.edu/event/52/

開催年月日： 2022年5月 - 2022年6月

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2022年3月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：大阪大学 吹田キャンパス   国名：日本国  

開催年月日： 2021年10月 - 2022年10月

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2021年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン   国名：日本国  

開催年月日： 2019年8月

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2019年5月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：Chine National Convention Center, Beijing   国名：中華人民共和国  

開催年月日： 2017年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：北海道大学   国名：日本国  

開催年月日： 2017年7月

記述言語：日本語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2017年5月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：東北大学   国名：日本国  

開催年月日： 2017年5月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：大阪市立大学   国名：日本国  

開催年月日： 2016年10月 - 2016年11月

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

その他リンク： http://www.crines.titech.ac.jp/ines5/

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種別：査読等 

外国語雑誌　査読論文数：2

日本語雑誌　査読論文数：0

国際会議録　査読論文数：0

国内会議録　査読論文数：0

種別：大会・シンポジウム等 

種別：査読等 

外国語雑誌　査読論文数：0

日本語雑誌　査読論文数：0

国際会議録　査読論文数：0

国内会議録　査読論文数：9

種別：大会・シンポジウム等 

参加者数：80