JAEA
  • help
  • PC | SP
  • JP | EN
          
検索対象：     
報告書番号：
※ 半角英数字
 年 ～ 
 年
全てクリア
検索結果：　200 件中 1件目～20件目を表示

発表形式

Initialising ...

選択項目を絞り込む

掲載資料名

Initialising ...

発表会議名

Initialising ...

筆頭著者名

Initialising ...

キーワード

Initialising ...

発表言語

Initialising ...

発行年

Initialising ...

開催年

Initialising ...

選択した検索結果をダウンロード

論文

Probing the nuclear interaction radius with single-proton transfer reactions

Liu, R.*; Yan, S.*; 西尾 勝久; 牧井 宏之; Orlandi, R.; 他17名*

Chinese Physics C, 50(9), p.094004_1 - 094004_6, 2026/09

https://doi.org/10.1088/1674-1137/ae7ff6

In this work, the measurements of $$^{56,58}Fe$$($$^{18}$$O, $$^{17}$$N)$$^{57,59}$$Co transfer reactions were carried out and Distorted Wave Born Approximation calculations were employed to reproduce the experimental data with the systematic heavy ion optical potential to investigate the interaction radius. The Coulomb barrier radii $$r_{rm B}$$ were determined to be 9.58$$pm$$0.35 fm and 9.83$$pm$$0.37 fm for $$^{18}$$O+$$^{56}$$Fe and $$^{18}$$O+$$^{58}$$Fe, respectively. The maximum distances between two nuclei surfaces were calculated to be 0.68$$pm$$0.35 fm for $$^{18}$$O+$$^{56}$$Fe and 0.85$$pm$$0.37 fm for $$^{18}$$O + $$^{58}$$Fe in this work, which provide a clear physical picture of the distance between two nuclei surfaces in single-nucleon transfer reactions.

論文

Deformation and magicity in heavy actinides; First observation of the ground-state rotational band of $$^{252}$$Fm

Orlandi, R.; 浅井 雅人; 牧井 宏之; 西尾 勝久; 廣瀬 健太郎; 塚田 和明; 佐藤 哲也; 伊藤 由太; 洲嵜 ふみ; 永目 諭一郎*; et al.

Physical Review Letters, 137(8), p.082501_1 - 082501_6, 2026/08

https://doi.org/10.1103/7gzt-ldn5

The ground-state rotational band of $$^{252}$$Fm ($$Z$$ = 100, $$N$$ = 152) was investigated using two different experimental setups at the JAEA Tandem Accelerator Laboratory. The first five $$gamma$$-ray transitions of the ground-state rotational band were observed for the first time. The new data revealed that $$^{252}$$Fm possesses the lowest first excited $$2^+$$ state energy, 41.88(16) keV, and the largest kinematic moment of inertia compared to neighboring isotopes in this region. These unique properties provide strong evidence for deformed shell gaps at $$Z$$ = 100 and $$N$$ = 152, revealing that $$^{252}$$Fm is a deformed doubly magic nucleus.

論文

Evolution of the nuclear structure in neutron-rich Cu isotopes; First spectroscopy of odd-odd $$^{74}$$Cu and $$^{76}$$Cu

Pedersen, L. G.*; Sahin, E.*; Orlandi, R.; 他64名*

European Physical Journal A, 62(6), p.114_1 - 114_18, 2026/06

https://doi.org/10.1140/epja/s10050-026-01873-w
 被引用回数：0 パーセンタイル：0.00(Physics, Nuclear)

This study reports the first spectroscopic observation of excited states in odd-odd isotopes $$^{74}$$Cu and $$^{76}$$Cu, following Ni $$beta$$ decay. Performed at RIKEN, the experiment analyzed $$gamma$$-ray coincidences to construct level schemes for these nuclei. The findings interpret the low-lying states as spin multiplets resulting from the coupling of specific single-particle orbitals (protons and neutrons). The results provide crucial data on how single-particle orbitals evolve in neutron-rich Cu isotopes and characterize the proton-neutron interaction near $$^{78}$$Ni. Furthermore, they constitute key benchmarks for nuclear structure theory, detailing orbital evolution in neutron-rich Cu. Most significantly, the non-observation of a predicted isomer, combined with observed decays, definitively assigns the spin-parity ($$pi = 1/2^+$$ vs $$pi = 3/2^-$$), resolving long-standing ambiguities for advanced shell-model calculations.

論文

Shape evolution in neutron-rich Rh isotopes; First measurement of negative-parity isomers in $$^{117,119}$$Rh

Zhang, 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

https://doi.org/10.1016/j.physletb.2025.140144
 被引用回数：0 パーセンタイル：0.00(Astronomy & Astrophysics)

At the RIKEN, $$beta$$-delayed $$gamma$$-ray spectroscopy studies were conducted on $$^{117}$$Rh and $$^{119}$$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 $$N$$=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 $$A sim 110$$ region, elucidating the interplay between triaxial deformation and shell evolution.

論文

Investigating the $$^{13}$$N($$alpha$$,$$p$$)$$^{16}$$O reaction rates via the $$^{19}$$F($$p$$,$$t$$)$$^{17}$$F reaction

Kim, S. H.*; Chae, K. Y.*; 浅井 雅人; 廣瀬 健太郎; 佐藤 哲也; 牧井 宏之; 西尾 勝久; Orlandi, R.; Smallcombe, J.; 洲嵜 ふみ; et al.

Journal of the Korean Physical Society, 6 Pages, 2026/00

https://doi.org/10.1007/s40042-026-01643-3
 被引用回数：0 パーセンタイル：0.00(Physics, Multidisciplinary)

コア崩壊超新星爆発(CCSNe)の元素合成シミュレーションにおいて、$$^{13}$$N($$alpha$$,$$p$$)$$^{16}$$O反応速度の不確実性が課題となっていた。本研究では、この反応を制約するため、JAEAタンデム加速器で$$^{19}$$F($$p$$,$$t$$)$$^{17}$$F遷移反応実験を実施した。得られたトリトンスペクトルと角度分布から、関連する$$^{17}$$F共鳴の崩壊特性(部分幅)を詳細に測定し、その結果を用いて反応速度パラメータを精密化した。これにより、CCSNe核合成モデルの信頼性向上が期待できる。

論文

Experimental determination of the resonance width and the branching ratio $$Gamma_{p1}$$/$$Gamma_{p0}$$ for the 19.40-MeV state in $$^{8}$$Be for studying the $$^{7}$$Be($$n$$,$$p1$$)$$^{7}$$Li$$^{*}$$ reaction relevant to the cosmological lithium problem

岩佐 直仁*; 西尾 勝久; 廣瀬 健太郎; 牧井 宏之; Orlandi, R.; 洲嵜 ふみ; Smallcombe, J.; 他7名*

Physical Review C, 112(3), p.035801_1 - 035801_6, 2025/09

https://doi.org/10.1103/jhgx-cht5
 被引用回数：2 パーセンタイル：70.29(Physics, Nuclear)

The $$^{7}$$Li($$^{3}$$He,$$d$$)$$^{8}$$Be$$^{*}$$($$p$$)$$^{7}$$Li reaction was measured at $$E_{lab}$$($$^{3}$$He) = 28 MeV for studying the $$^{7}$$Be($$n$$,$$p1$$)$$^{7}$$Li$$^{*}$$ reaction, which is a $$^{7}$$Be destruction reaction in the big bang nucleosynthesis. Resonant states at 18.9$$-$$20.1 MeV in $$^{8}$$Be were populated by the $$^{7}$$Li($$^{3}$$He,$$d$$)$$^{8}$$Be$$^{*}$$ reaction and decay protons to the ground ($$p0$$) and first-excited states ($$p1$$) in $$^{7}$$Li were well separated and measured. The resonance width $$Gamma$$ and branching ratio $$Gamma_{p1}$$/$$Gamma_{p0}$$ for the 19.40-MeV state in $$^{8}$$Be were deduced to be 342$$pm$$112 keV and 11.2 $$pm$$ 3.5 $$pm$$ 5.0 (syst.)%, respectively. The $$7$$Be($$n$$,$$p1$$)$$^{7}$$Li$$^{*}$$ reaction cross section was deduced.

論文

Excited-state lifetimes in $$^{131}$$In, $$^{131}$$Sn, and $$^{136}$$Te measured with the HiCARI $$gamma$$-ray spectrometer at RIBF at RIKEN

Acosta, J.*; Jungclaus, A.*; Armstrong, M.*; G$'o$rska, M.*; Parry, T.*; Orlandi, R.; 他29名*

Physical Review C, 111(6), p.064316_1 - 064316_12, 2025/06

https://doi.org/10.1103/mysq-byyv
 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 $$gamma$$-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 $$^{131}$$In, $$^{131}$$Sn, and $$^{136}$$Te, characterizing the array and establishing reliable analytical methods. The obtained half-lifes were compared with existing experimental results and theoretical calculations.

論文

Seniority structure in neutron-rich nucleus $$^{128}$$Ag; Evidence for robustness of $$N$$=82 shell closure in silver isotopes

Luo, D. W.*; Zhang, J. Z.*; Li, Z. H.*; Orlandi, R.; 他64名*

Physical Review Letters, 134(23), p.232502_1 - 232502_7, 2025/06

https://doi.org/10.1103/wq9m-trj8
 被引用回数：4 パーセンタイル：79.04(Physics, Multidisciplinary)

The first spectroscopic study of the neutron-rich $$^{128}$$Ag isotope at RIBF-RIKEN revealed a new 1.60(7) $$mu$$s seniority isomer with a proposed 16$$^{-}$$ spin-parity. Shell model calculations accurately describe its level structure, consistent with seniority schemes in nearby odd-odd nuclei. Level inversions between $$^{128}$$Ag and $$^{130}$$In's lowest states are linked to seniority-nonconserving interactions. The structure above 10$$^{-}$$ shows similarities to seniority structures in $$^{128}$$Pd and $$^{130}$$Cd, confirming the robustness of the $$N$$=82 shell closure in silver isotopes.

論文

Competition between mass-symmetric and asymmetric fission modes in $$^{258}$$Md produced in the $$^{4}$$He + $$^{254}$$Es reaction

西尾 勝久; 廣瀬 健太郎; 牧井 宏之; Orlandi, R.; Kean, K. R.*; 塚田 和明; 豊嶋 厚史*; 浅井 雅人; 佐藤 哲也; Chiera, N. M.*; et al.

Physical Review C, 111(4), p.044609_1 - 044609_12, 2025/04

https://doi.org/10.1103/PhysRevC.111.044609
 被引用回数：1 パーセンタイル：47.92(Physics, Nuclear)

In spontaneous fission (SF) it is found that the mass-asymmetric fission of well-known actinides suddenly changes to the symmetric fission when nucleus has a mass number $$A_{c}$$ larger than 257. We have measured for the first time fission-fragment mass and total-kinetic-energy (TKE) distributions of the excited compound nucleus $$^{258}$$Md, populated in the reaction $$^{4}$$He+$$^{254}$$Es, using the rare isotope $$^{254}$$Es with a short half-life, $$T_{1/2}$$=276 days. The fission of $$^{258}$$Md can be interpreted as involving 3 fission modes: an mass-asymmetric mode and two modes of mass-asymmetric fissions, the latter two are manifested by different TKE values. Predominantly symmetric fission was obtained at the excitation energy of 15.0 MeV. By increasing the energy to 18.0 MeV, the asymmetric fission mode dominates. Both such a strong change of fission modes within a small increase of excitation energy and the enhancement of asymmetric split are new phenomena in fission.

論文

Spectroscopic study of $$^{97}$$Mo, $$^{99}$$Mo, and $$^{101}$$Mo

Kumar, V.*; Chapman, R.*; Ollier, J.*; Orlandi, R.; Smith, J. F.*; Spohr, K.-M.*; Torres, D. A.*; Wady, P.*; 他10名*

Physical Review C, 110(4), p.044308_1 - 044308_18, 2024/10

https://doi.org/10.1103/PhysRevC.110.044308
 被引用回数：4 パーセンタイル：64.34(Physics, Nuclear)

Excited states of the molybdenum isotopes $$^{97,99,101}$$Mo were populated in two experiments which used fusion-fission and binary grazing reactions. In the first experiment, the GASP array of Ge detectors was used to detect $$gamma$$ rays from fusion-fission products from the $$^{36}$$S + $$^{176}$$Yb reaction at 230 MeV. In the multinucleon transfer experiment, a 530-MeV beam of $$^{96}$$Zr ions was incident on a thin $$^{124}$$Sn target; projectile-like ejectiles were detected and identified using the PRISMA magnetic spectrometer and their associated $$gamma$$ rays detected using the CLARA array of Clover detectors. Previously known bands were extended in all isotopes, and a new g$$_{7/2}$$ band was established in $$^{101}$$Mo. The observed level schemes were compared with shell-model calculations, which reproduce the general features of the energy spectrum of excited states of $$^{97}$$Mo, $$^{99}$$Mo, and $$^{101}$$Mo, although not in detail. For the h$$_{11/2}$$ negative-parity decay sequences of the three isotopes studied, evidence is presented for nuclear shape changes with increasing neutron number.

論文

Excited-state half-lives in $$^{130}$$Cd and the isospin dependence of effective charges

Jungclaus, A.*; G$'o$rska, M.*; Mikolajczuk, M.*; Acosta, J.*; Taprogge, J.*; 西村 俊二*; Doornenbal, P.*; Orlandi, R.; 他55名*

Physical Review Letters, 132(22), p.222501_1 - 222501_7, 2024/05

https://doi.org/10.1103/PhysRevLett.132.222501
 被引用回数：8 パーセンタイル：76.19(Physics, Multidisciplinary)

At the RIBF facility in RIKEN, the half-lives of the 6$$^+$$ and 8$$^+$$ excited states of semi-magic nucleus $$^{130}$$Cd were measured, and the B(E2) transition matrix elements of the corresponding transitions were deduced. This information was used to determine the effective proton charges in $$^{130}$$Cd. By comparing these new results with the effective charges deduced from a previous measurement of $$^{98}$$Cd, the effective charges near doubly magic $$^{100}$$Sn and $$^{132}$$Sn could be compared for the first time. This revealed an unexpected large decrease of the isovector effective charges due to the increasing number of neutrons. This information is very important for state-of-the-art large scale shell model calculations.

論文

Spectroscopy of neutron-rich Fe isotopes populated in the $$^{70}$$Zn+$$^{238}$$U reaction

Benito, J.*; Lenzi, S. M.*; Recchia, F.*; Axiotis, M.*; Aydin, S.*; Bazzacco, D.*; Benzoni, G.*; Orlandi, R.; 他37名*

Acta Physica Polonica B; Proceedings Supplement, 17(3), p.3-A4_1 - 3-A4_7, 2024/04

https://doi.org/10.5506/APhysPolBSupp.17.3-A4
 被引用回数：0 パーセンタイル：0.00(Physics, Multidisciplinary)

Excited states of neutron-rich $$^{64,66,68}$$Fe isotopes have been studied through a multinucleon transfer reaction of a $$^{70}$$Zn beam on a $$^{238}$$U target at the National Laboratories of Legnaro, Italy. The magnetic spectrometer PRISMA was used to identified the isotopes produced in the reaction, and the CLARA array of Clover Ge detectors to detect their gamma rays. The obtained level scheme were compared with new, state-of-the-art large scale shell model calculations. The large model space used in the calculation, which included the 2d$$_{5/2}$$ orbital, revealed that this orbit is key in order to obtain excellent agreement between the calculations and the experimental data.

論文

Search for the 6$$alpha$$ condensed state in $$^{24}$$Mg using the $$^{12}$$C+$$^{12}$$C scattering

Fujikawa, Y.*; Kawabata, T.*; Adachi, S.*; 廣瀬 健太郎; 牧井 宏之; 西尾 勝久; Orlandi, R.; 洲嵜 ふみ; 他13名*

Physics Letters B, 848, p.138384_1 - 138384_6, 2024/01

https://doi.org/10.1016/j.physletb.2023.138384
 被引用回数：12 パーセンタイル：82.31(Astronomy & Astrophysics)

We searched for the 6$$alpha$$-condensed state in $$^{24}$$Mg by measuring the $$^{12}$$C+$$^{12}$$C scattering with the SAKRA Si detector array. By using the invariant-mass method for the detected 3$$alpha$$ particles, the inclusive cross sections for the $$^{12}$$C+$$^{12}$$C $$rightarrow$$ $$^{12}$$C(0$$^{+}_{2}$$) + X and $$^{12}$$C(3$$^{-}_{1}$$) + X reactions were determined. In both the inclusive $$^{12}$$C(0$$^{+}_{2}$$) + X channel and the exclusive $$^{12}$$C(0$$^{+}_{2}$$) + $$^{12}$$C(0$$^{+}_{1}$$) channel, the cross section peaked at E$$_{cm}$$ = 19.4 MeV, which correspond to the excitation energy of E$$_{x}$$ = 33.3 MeV in $$^{24}$$Mg. This 19.4-MeV state is a candidate for the 6$$alpha$$-condensed state

論文

Evolution of nuclear structure in the neutron-rich $$^{96,97,99}$$Nb isotopes; Evidence for shape coexistence in $$N$$=58 $$^{99}$$Nb

Kumar, V.*; Chapman, R.*; O'Donnell, D.*; Ollier, J.*; Orlandi, R.; Smith, J. F.*; Spohr, K.-M.*; Torres, D. A.*; 他13名*

Physical Review C, 108(4), p.044313_1 - 044313_19, 2023/10

https://doi.org/10.1103/PhysRevC.108.044313
 被引用回数：5 パーセンタイル：58.11(Physics, Nuclear)

The nuclear structure of neutron-rich niobium isotopes $$^{96,97,98}$$Nb were studied at the Legnaro National Laboratories using $$gamma$$-ray spectroscopy. The isotopes were produced in two different experiments, either using multi-nucleon transfer reactions of $$^{96}$$Zr 530-MeV beam onto a $$^{124}$$Sn target, or via fusion-fission of $$^{36}$$S on $$^{176}$$Yb. The level schemes of these isotopes were extended respectively up to excitation energies of 4545, 5409, and 3814 keV. The structure of the low-lying states in these isotopes was interpreted and discussed in the context of shell-model calculations. In particular, for the $$^{99}$$Nb isotope ($$Z$$=41, $$N$$=58), the results indicate the presence of shape-coexistence at low-energies, which was observed for the first time in this isotope.

論文

Experimental level scheme of $$^{78}$$Cu

Pedersen, L. G.*; Sahin, E.*; G$"o$rgen, A.*; Bello Garrote, F. L.*; Orlandi, R.; 他61名*

Acta Physica Polonica B; Proceedings Supplement, 16(4), p.4-A14_1 - 4-A14_6, 2023/08

https://doi.org/10.5506/APhysPolBSupp.16.4-A14
 被引用回数：0 パーセンタイル：0.00(Physics, Multidisciplinary)

Excited states in $$^{78}$$Cu were observed for the first time following the $$beta$$ decay of $$^{78}$$Ni created by in-flight fission of $$^{238}$$U. Based on the coincidences with the observed $$gamma$$-ray transitions, a level scheme comprising eight excited states was constructed, with tentative spin assignments for 5 of them. In addition to the $$gamma$$-decaying states, an isomeric state with a lifetime of 3.8(4) ms was also found to decay by internal conversion.

論文

Measurement of double-differential neutron yields for iron, lead, and bismuth induced by 107-MeV protons for research and development of accelerator-driven systems

岩元 大樹; 中野 敬太; 明午 伸一郎; 佐藤 大樹; 岩元 洋介; 杉原 健太*; 西尾 勝久; 石 禎浩*; 上杉 智教*; 栗山 靖敏*; et al.

EPJ Web of Conferences, 284, p.01023_1 - 01023_4, 2023/05

https://doi.org/10.1051/epjconf/202328401023
 被引用回数：0 パーセンタイル：0.00(Nuclear Science & Technology)

加速器駆動システム(ADS)の核特性予測精度の向上と京都大学臨界集合体実験装置(KUCA)におけるADS炉物理実験で用いる中性子源情報の取得を目的として、京都大学の固定磁場強集束(FFAG)加速器を用いた核データ測定実験プログラムを開始した。このプログラムの一環として、鉄,鉛及びビスマスに対する陽子入射二重微分中性子収量(TTNY)及び断面積(DDX)を測定した。測定では、真空チェンバ内に設置された標的試料に107MeVの陽子ビームを照射し、核反応によって標的から発生した粒子の信号を、小型の中性子検出器を用いて検出した。検出信号とFFAGキッカー電磁石の信号の時間差から飛行時間(TOF)を求め、ガンマ線の事象を波形弁別法によって除去して中性子事象をカウントすることで中性子のTOFスペクトルを求めた。得られた中性子のTOFスペクトルから、相対論的運動学によりTTNY及びDDXを求めた。実験で得られたTTNY及びDDXを、モンテカルロ輸送計算コードPHITSによる計算と比較し、PHITSに組み込まれた核反応モデル及び評価済み核データライブラリJENDL-4.0/HEの妥当性を検証するとともに、PHITSによる計算の予測精度を評価した。

論文

Measurement of 107-MeV proton-induced double-differential thick target neutron yields for Fe, Pb, and Bi using a fixed-field alternating gradient accelerator at Kyoto University

岩元 大樹; 中野 敬太; 明午 伸一郎; 佐藤 大樹; 岩元 洋介; 杉原 健太; 西尾 勝久; 石 禎浩*; 上杉 智教*; 栗山 靖敏*; et al.

Journal of Nuclear Science and Technology, 60(4), p.435 - 449, 2023/04

https://doi.org/10.1080/00223131.2022.2115423
 被引用回数：4 パーセンタイル：39.28(Nuclear Science & Technology)

加速器駆動核変換システム(ADS)の研究開発及び京都大学臨界実験装置(KUCA)におけるADS未臨界炉物理の基礎研究を目的として、固定磁場強収束(FFAG)加速器を用いて107MeV陽子による鉄、鉛及びビスマス標的に対する二重微分中性子収量(TTNY)を測定した。TTNYは8個の中性子検出器(各検出器は小型のNE213液体有機シンチレータと光電子増倍管より構成される)からなる中性子検出器システムを用いて飛行時間法により得られたものである。測定で得られたTTNYを、粒子・重イオン輸送コードシステム(PHITS)に組み込まれたモンテカルロ法に基づく核破砕反応モデル(INCL4.6/GEM, Bertini/GEM, JQMD/GEM, JQMD/SMM/GEM)及び評価済み高エネルギー核データライブラリ(JENDL-4.0/HE)による計算結果と比較した。JENDL-4.0/HEを含む比較対象のモデルは、検出器角度5度における高エネルギーピークを再現しないなどの特徴的な不一致が見られた。測定で得られたTTNYとPHITSによって評価した20MeV以下のエネルギー及び角度積分中性子収率を比較した結果、INCL4.6/GEMがKUCAにおけるADS炉物理実験のモンテカルロ輸送シミュレーションに適していることが示された。

論文

First spectroscopic study of odd-odd $$^{78}$$Cu

Pedersen, L. G.*; Sahin, E.*; G$"o$rgen, A.*; Bello Garrote, F. L.*; 角田 佑介*; 大塚 孝治*; 新倉 潤*; Orlandi, R.; 他59名*

Physical Review C, 107(4), p.044301_1 - 044301_10, 2023/04

https://doi.org/10.1103/PhysRevC.107.044301
 被引用回数：4 パーセンタイル：50.66(Physics, Nuclear)

Nuclei in the vicinity of $$^{78}$$Ni ($$Z$$=28, $$N$$=50) are important benchmarks to study the evolution of shell structure far from stability. Excited states in $$^{78}$$Cu were observed for the first time following the $$beta$$-decay of $$^{78}$$Ni, which was produced by in-flight fission of $$^{238}$$U. Using $$gamma$$-ray coincidences, a level scheme comprising eight excited states was built. Using the observed $$beta$$ feeding and the $$gamma$$-decay properties of the excited states, spin was tentatively assigned to 5 new states. In addition to the $$gamma$$-decaying states, an isomeric state with a lifetime of 3.8(4) ms was found to decay by internal conversion. By comparing the results with large scale shell model calculations, quantitative information about the proton-neutron interaction outside the doubly magic $$^{78}$$Ni core was obtained.

論文

京都大学FFAG加速器を用いた加速器駆動型核変換システム(ADS)用核データの実験的研究

岩元 大樹; 明午 伸一郎; 中野 敬太*; 佐藤 大樹; 岩元 洋介; 杉原 健太*; 石 禎浩*; 上杉 智教*; 栗山 靖敏*; 八島 浩*; et al.

Proceedings of 19th Annual Meeting of Particle Accelerator Society of Japan (インターネット), p.404 - 409, 2023/01

https://www.pasj.jp/web_publish/pasj2022/proceedings/PDF/TUP0/TUP040.pdf

加速器駆動核変換システム(ADS)の研究開発に資するため、固定磁場強収束(FFAG)加速器を用い、核データを取得する実験的研究プログラムを開始した。ADSの核設計及び京都大学臨界集合体実験装置(KUCA)における未臨界実験体系の解析で重要となる、鉛及びビスマスの陽子入射中性子収量及び核分裂に関する核データを対象とした。中性子の飛行時間(TOF)測定で要求される短パルスビームの技術開発を行い、その要求値となるビーム幅10ns以下を達成するとともに、107MeV陽子入射による厚い標的中性子収量TTNY及び中性子生成二重微分断面積DDXをTOF法により測定した。TTNY及びDDXの測定には、小型シンチレータと光電子増倍管から構成される中性子検出器を用いた。測定で得られた結果をADSの核設計で用いられるPHITSによる解析値と比較した。さらに、マイクロチャンネルプレート(MCP)と多芯線比例計数管(MWPC)を組み合わせにより、107MeV陽子入射の$$^{208}$$Pb核分裂反応から生成される核分裂片の質量数分布を測定した。本プログラムの最終年度となる令和4年度は、$$^{209}$$Biに対する核分裂片の質量数分布と核分裂で生じる核分裂中性子の測定を実施するとともに、$$^{237}$$Np核分裂計数管を用いて、陽子と標的との核反応で形成される中性子場の測定を実施する予定である。

論文

New $$K$$ isomers in $$^{248}$$Cf

Orlandi, R.; 牧井 宏之; 西尾 勝久; 廣瀬 健太郎; 浅井 雅人; 塚田 和明; 佐藤 哲也; 伊藤 由太; 洲嵜 ふみ; 永目 諭一郎*; et al.

Physical Review C, 106(6), p.064301_1 - 064301_11, 2022/12

https://doi.org/10.1103/PhysRevC.106.064301
 被引用回数：6 パーセンタイル：55.50(Physics, Nuclear)

The nuclear structure of $$^{248}$$Cf produced by the $$^{18}$$O+$$^{249}$$Cf multinucleon transfer reaction was investigated using $$gamma$$-ray spectroscopy. Analysis of the $$gamma$$-ray spectrum of $$^{248}$$Cf revealed the presence of multiple long-lived (isomeric) excited states at low excitation energies. The energies and half-lives of the isomers contain information on the proton and neutron orbits in the heavy-element region and the deformation of atomic nuclei, and are important data to predict the properties of nuclei in the "island of stability".

200 件中 1件目～20件目を表示