Understanding of the r-process environment through the precise nuclear spectroscopic works of the unknown nuclei in the vicinity of neutron magic number N=126

• Project/Area Number: 17H01132
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Particle/Nuclear/Cosmic ray/Astro physics
• Research Institution: High Energy Accelerator Research Organization
• Principal Investigator: HIRAYAMA Yoshikazu 大学共同利用機関法人高エネルギー加速器研究機構, 素粒子原子核研究所, 研究機関講師 (30391733)
• Co-Investigator(Kenkyū-buntansha): 宮武 宇也 大学共同利用機関法人高エネルギー加速器研究機構, 素粒子原子核研究所, 教授 (50190799) ; 渡邉 裕 大学共同利用機関法人高エネルギー加速器研究機構, 素粒子原子核研究所, 准教授 (50353363)
• Project Period (FY): 2017-04-01 – 2021-03-31
• Project Status: Completed (Fiscal Year 2020)
• Budget Amount: ¥45,240,000 (Direct Cost: ¥34,800,000、Indirect Cost: ¥10,440,000); Fiscal Year 2020: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2019: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2018: ¥20,280,000 (Direct Cost: ¥15,600,000、Indirect Cost: ¥4,680,000); Fiscal Year 2017: ¥22,230,000 (Direct Cost: ¥17,100,000、Indirect Cost: ¥5,130,000)
• Keywords: 元素合成 / レーザー共鳴イオン化 / 質量測定 / 国際情報交換 / ベルギー / レーザー共鳴イオン化核分光 / 実験核物理

Outline of Final Research Achievements

In order to study the properties of heavy short-lived nuclei more precisely, we have successfully developed the following three items; (1) laser system and related equipment for the precise laser resonance ionization spectroscopy of the short-lived nuclei which are in the gas-jet with good directivity, (2) 3 dimensional-tracking-type multi-segmented proportional gas counter with high detection efficiency and low background rate to detect the electrons emitted from rare short-lived nuclei for the precise nuclear decay spectroscopy, (3) install and operation of multi-reflection time of flight mass-spectrograph in order to measure the nuclear mass with one millionth precision. By using the equipment, we could successfully measure the nuclear half-lives and masses of rare heavy nuclei produced at the KISS (KEK isotope separation system) facility.

Academic Significance and Societal Importance of the Research Achievements

精密な短寿命核の性質（崩壊寿命や質量）を測定可能な実験装置を開発し、これらを駆使して187Ta、198Irなど約２０種類程の希少短寿命核の性質を研究した。これらの希少短寿命核は非常に高温（10億度）で高い中性子密度の星の中で生成されたと考えられている。その性質を研究することは、金や白金といった身の回りに存在する重い安定な元素が誕生した天体環境の謎を解き明かす上で不可欠であり、学術的意義は非常に高い。

Research Products

• [Int'l Joint Research] KU Leuven(ベルギー)
• [Int'l Joint Research] Institute of Basic Science(韓国)
• [Int'l Joint Research] 北京航空航天大学(中国)
• [Int'l Joint Research] Surrey University(英国)
• [Int'l Joint Research] KU Leuven(ベルギー)
• [Int'l Joint Research] Surrey University(英国)
• [Int'l Joint Research] IBS RISP(韓国)
• [Int'l Joint Research] 北京航空航天大学(中国)
• [Int'l Joint Research] KU Leuven(ベルギー)
• [Int'l Joint Research] IBS(韓国)
• [Int'l Joint Research] IBS(韓国)
• [Int'l Joint Research] University of Surrey/Univ. Brighton(英国)
• [Int'l Joint Research] Argonne Nat. Lab.(米国)
• [Int'l Joint Research] Australian Nat. Univ.(オーストラリア)
• [Int'l Joint Research] GSI(ドイツ)
• [Int'l Joint Research]
• [Journal Article] Three-dimensional tracking multi-segmented proportional gas counter for β-decay spectroscopy of unstable nuclei (2021)
  • Author(s): Hirayama Y.、Schury P.、Mukai M.、Choi H.、Iimura S.、Watanabe Y.X.、Wada M.、Watanabe H.、Miyatake H.
  • Journal Title: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment Volume: 997 Pages: 165152-165152
  • DOI: 10.1016/j.nima.2021.165152
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Beta decay of the axially asymmetric ground state of 192Re (2021)
  • Author(s): Watanabe H.、Watanabe Y.X.、Hirayama Y.、Andreyev A.N.、Hashimoto T.、Kondev F.G.、Lane G.J.、Litvinov Yu.A.、Liu J.J.、Miyatake H.、Moon J.Y.、Morales A.I.、Mukai M.、Nishimura S.、Niwase T.、Rosenbusch M.、Schury P.、Shi Y.、Wada M.、Walker P.M.
  • Journal Title: Physics Letters B Volume: 814 Pages: 136088-136088
  • DOI: 10.1016/j.physletb.2021.136088
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Nuclear spectroscopy of r-process nuclei using KEK Isotope Separation System (2020)
  • Author(s): Hirayama Y.、Watanabe Y.X.、Mukai M.、Ahmed M.、Ishiyama H.、Jeong S.C.、Kakiguchi Y.、Kimura S.、Moon J.Y.、Oyaizu M.、Park J.H.、Schury P.、Wada M.、Miyatake H.
  • Journal Title: Journal of Physics: Conference Series Volume: 1643 Pages: 012138-012138
  • DOI: 10.1088/1742-6596/1643/1/012138
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Properties of Ta187 Revealed through Isomeric Decay (2020)
  • Author(s): Walker P.M.、Hirayama Y.、Lane G.J.、Watanabe H.、Dracoulis G.D.、Ahmed M.、Brunet M.、Hashimoto T.、Ishizawa S.、Kondev F.G.、Litvinov Yu.A.、Miyatake H.、Moon J.Y.、Mukai M.、Niwase T.、Park J.H.、Podolyk Zs.、Rosenbusch M.、Schury P.、Wada M.、Watanabe X.Y.、Liang W.Y.、Xu F.R.
  • Journal Title: Physical Review Letter Volume: 125 Pages: 192505-192505
  • DOI: 10.1103/physrevlett.125.192505
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] In-gas-cell laser resonance ionization spectroscopy of Ir196,197,198 (2020)
  • Author(s): Mukai M.、Hirayama Y.、Watanabe Y. X.、Schiffmann S.、Ekman J.、Godefroid M.、Schury P.、Kakiguchi Y.、Oyaizu M.、Wada M.、Jeong S. C.、Moon J. Y.、Park J. H.、Ishiyama H.、Kimura S.、Ueno H.、Ahmed M.、Ozawa A.、Watanabe H.、Kanaya S.、Miyatake H.
  • Journal Title: PHYSICAL REVIEW C Volume: 102 Pages: 054307-054307
  • DOI: 10.1103/physrevc.102.054307
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] In-gas-cell laser ionization spectroscopy of Os194,196 isotopes by using a multireflection time-of-flight mass spectrograph (2020)
  • Author(s): Choi H.、Hirayama Y.、Choi S.、Hashimoto T.、Jeong S. C.、Miyatake H.、Moon J. Y.、Mukai M.、Niwase T.、Oyaizu M.、Rosenbusch M.、Schury P.、Taniguchi A.、Watanabe Y. X.、Wada M.
  • Journal Title: PHYSICAL REVIEW C Volume: 102 Pages: 034309-034309
  • DOI: 10.1103/physrevc.102.034309
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Deexcitation γ-ray transitions from the long-lived Iπ=13/2+ metastable state in Os195 (2020)
  • Author(s): Watanabe Y. X.、Ahmed M.、Hirayama Y.、Mukai M.、Park J. H.、Schury P.、Kakiguchi Y.、Kimura S.、Ozawa A.、Oyaizu M.、Wada M.、Miyatake H.
  • Journal Title: PHYSICAL REVIEW C Volume: 101 Pages: 041305-041305
  • DOI: 10.1103/physrevc.101.041305
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Nuclear spectroscopy of r-process nuclei using KEK Isotope Separation System (2020)
  • Author(s): Y. Hirayama, Y.X. Watanabe, M. Mukai, P. Schury, M. Ahmed, H. Ishiyama, S.C. Jeong, Y. Kakiguchi, S. Kimura, J.Y. Moon, M. Oyaizu, J.H. Park, M. Wada, H. Miyatake
  • Journal Title: Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms Volume: 463 Pages: 425-430
  • DOI: 10.1016/j.nimb.2019.04.035
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Development of a multi-segmented proportional gas counter for β-decay spectroscopy at KISS (2020)
  • Author(s): M. Mukai, Y. Hirayama, P. Schury, Y.X. Watanabe, M. Ahmed, H. Haba, H. Ishiyama, S.C. Jeong , Y. Kakiguchi, S. Kimura, J.Y. Moon, M. Oyaizu, A. Ozawa, J.H. Park, H. Ueno, M. Wada, H. Miyatake
  • Journal Title: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms Volume: 463 Pages: 421-424
  • DOI: 10.1016/j.nimb.2019.04.036
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Efficient two-color two-step laser ionization schemes of λ1 ~250 nm and λ2 = 307.9 nm for heavy refractory elements-Measurements of ionization cross-sections and hyperfine spectra of tantalum and tungsten (2019)
  • Author(s): Y. Hirayama, M. Mukai, Y. X. Watanabe, M. Oyaizu, S. C. Jeong, Y. Kakiguchi, P. Schury, M. Wada, and H. Miyatake
  • Journal Title: Review of Scientific Instruments Volume: 90 Pages: 115104-115104
  • DOI: 10.1063/1.5124444
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] KEK Isotope Separation System (KISS) (2018)
  • Author(s): Y. Watanabe, Y. Hirayama, H. Miyatake
  • Journal Title: Nuclear Physics News Volume: 28 Pages: 25-28
  • DOI: 10.1080/10619127.2018.1529984
  • Peer Reviewed / Open Access
• [Journal Article] β- and γ-decay spectroscopy of 197,198Os (2018)
  • Author(s): Y. Hirayama, Y. X. Watanabe, M. Mukai, M. Ahmed, S. C. Jeong, Y. Kakiguchi, S. Kimura, M. Oyaizu, J. H. Park, P. Schury, M. Wada, H. Watanabe, and H. Miyatake
  • Journal Title: Phys. Rev. C Volume: 98
  • DOI: 10.1103/physrevc.98.014321
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Present status of the KISS project (2018)
  • Author(s): H. Miyatake, M. Wada, X. Y. Watanabe, Y. Hirayama, P. Schury, M. Ahmed3, H. Ishiyama, S. C. Jeong, Y. Kakiguchi, S. Kimura, J. Y. Moon, M. Mukai, M. Oyaizu, and J. H. Park
  • Journal Title: AIP Conf. Proc. Volume: 1947
  • DOI: 10.1063/1.5030822
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] High-efficiency and low-background multi-segmented proportional gas counter for β-decay spectroscopy (2018)
  • Author(s): Mukai M.、Hirayama Y.、Watanabe Y.X.、Schury P.、Jung H.S.、Ahmed M.、Haba H.、Ishiyama H.、Jeong S.C.、Kakiguchi Y.、Kimura S.、Moon J.Y.、Oyaizu M.、Ozawa A.、Park J.H.、Ueno H.、Wada M.、Miyatake H.
  • Journal Title: Nucl. Instrum. Methods A Volume: 884 Pages: 1-10
  • DOI: 10.1016/j.nima.2017.12.013
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Doughnut-shaped gas cell for KEK Isotope Separation System (2017)
  • Author(s): Hirayama Y.、Watanabe Y.X.、Mukai M.、Oyaizu M.、Ahmed M.、Ishiyama H.、Jeong S.C.、Kakiguchi Y.、Kimura S.、Moon J.Y.、Park J.H.、Schury P.、Wada M.、Miyatake H.
  • Journal Title: Nucl. Instrum. Methods B Volume: 412 Pages: 11-18
  • DOI: 10.1016/j.nimb.2017.08.037
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Ionization cross section, pressure shift and isotope shift measurements of osmium (2017)
  • Author(s): Hirayama Yoshikazu、Mukai Momo、Watanabe Yutaka、Oyaizu Michihiro、Ahmed Murad、Kakiguchi Yutaka、Kimura Sota、Miyatake Hiroari、Schury Peter、Wada Michiharu、Jeong Sun-Chan
  • Journal Title: J. of Phys. B Volume: 50 Pages: 215203-215203
  • DOI: 10.1088/1361-6455/aa8b50
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] In-gas-cell laser spectroscopy of the magnetic dipole moment of the N~126 isotope 199Pt (2017)
  • Author(s): Y. Hirayama, M. Mukai, Y. X. Watanabe, M. Ahmed, S. C. Jeong, H. S. Jung, Y. Kakiguchi, S. Kanaya, S. Kimura, J. Y. Moon, T. Nakatsukasa, M. Oyaizu, J. H. Park, P. Schury, A. Taniguchi, M. Wada, K. Washiyama, H. Watanabe, and H. Miyatake
  • Journal Title: Phys. Rev. C Volume: 96 Pages: 014307-014307
  • DOI: 10.1103/physrevc.96.014307
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Presentation] KISS、MRTOFを用いた核分光実験の現状 (2021)
  • Author(s): 渡辺 裕
  • Organizer: 令和2年度専門研究会「短寿命RIを用いた核分光と核物性研究Ⅶ」
  • Invited
• [Presentation] Nuclear spectroscopy at KISS (2020)
  • Author(s): 平山 賀一
  • Organizer: Symposium on Nuclear Data 2020
  • Invited
• [Presentation] Study of nuclear structure in the vicinity of N=126 at KISS (2020)
  • Author(s): Yoshikazu Hirayama
  • Organizer: Vth Topical Workshop on Modern Aspects in Nuclear Structure, Bormio, Italy, Feb. 4-9, 2020
  • Int'l Joint Research / Invited
• [Presentation] KISSでの核分光研究 (2020)
  • Author(s): Hiroari Miyatake
  • Organizer: 令和元年度KUR専門研究会「短寿命RIを用いた核分光と核物性研究Ⅵ」 兼「第11回停止・低速RIビームを用いた核分光研究会」、京大複合原子力科学研、1/ 16-17, 2020
• [Presentation] KISS Project (2019)
  • Author(s): Hiroari Miyatake
  • Organizer: 14th Asia-Pacific Physics Conference, Borneo, Nov. 17-22, 2019
  • Int'l Joint Research / Invited
• [Presentation] KISSでのガスジェット内レーザー共鳴イオン化核分光 (2019)
  • Author(s): 平山 賀一
  • Organizer: 日本物理学会2019年秋季大会、山形大学、9/17-20, 2019
• [Presentation] 第7周期元素科学：超重元素の物理と化学 (2019)
  • Author(s): Hiroari Miyatake
  • Organizer: 日本物理学会2019年秋季大会、山形大学、9/17, 2019
  • Invited
• [Presentation] Nuclear physics by multi-reflection time-of-flight mass spectrograph at WNSC (2019)
  • Author(s): Peter Schury
  • Organizer: INPC 2019 Glasgow, Jul. 29-Aug. 2, 2019
  • Int'l Joint Research / Invited
• [Presentation] Nuclear spectroscopy of r-process nuclei in the vicinity of N=126 by using KISS (2019)
  • Author(s): Yoshikazu Hirayama
  • Organizer: INPC 2019 Glasgow, Jul. 29-Aug. 2, 2019
  • Int'l Joint Research
• [Presentation] Present status and future plans for slow and stopped beams in RIKEN (2019)
  • Author(s): Peter Schury
  • Organizer: SMI-2019 Montreal, Jul. 16-19, 2019
  • Int'l Joint Research / Invited
• [Presentation] Recent experimental results of KEK Isotope Separation System (KISS) (2019)
  • Author(s): Yutaka Watanabe
  • Organizer: SMI-2019 Montreal, Jul. 16-19, 2019
• [Presentation] Nuclear spectroscopy of r-process nuclei in the vicinity of N=126 at KISS (2019)
  • Author(s): Yoshikazu Hirayama
  • Organizer: Physics between lead and uranium: in preparation of new experimental campaigns at ISOLDE, Leuven, Apr. 16-18, 2019
  • Int'l Joint Research / Invited
• [Presentation] Production of N=126 nuclei and beyond using multinucleon transfer reactions (2019)
  • Author(s): Yutaka Watanabe
  • Organizer: Physics between lead and uranium: in preparation of new experimental campaigns at ISOLDE, Leuven, Apr. 16-18, 2019
  • Int'l Joint Research / Invited
• [Presentation] Nuclear spectroscopy of r-process nuclei in the vicinity of N = 126 at KISS (2019)
  • Author(s): Yoshikazu Hirayama
  • Organizer: 日本物理学会第74回年次大会
  • Invited
• [Presentation] KISS/MRTOFの現状 (2018)
  • Author(s): Hiroari Miyatake
  • Organizer: 平成30年度KUR専門研究会「短寿命RIを用いた核分光と核物性研究Ⅴ」
• [Presentation] β-γ spectroscopy of neutron-rich nucleus 195Os (2018)
  • Author(s): MD. Murad Ahmed
  • Organizer: 13th International Conference on Nucleus-Nucleus Collisions (NN2018)
  • Int'l Joint Research
• [Presentation] KISS and MRTOF Projects of KEK (2018)
  • Author(s): Peter Schury
  • Organizer: The 10th China-Japan Joint Nuclear Physics Symposium (CJNP 2018)
  • Int'l Joint Research / Invited
• [Presentation] RNB project on the astrophysical element synthesis (2018)
  • Author(s): Hiroari Miyatake
  • Organizer: Tsukuba Global Science Week 2018 (TGSW2018)@Tsukuba International Congress Center
  • Int'l Joint Research
• [Presentation] Nuclear production by multinucleon transfer reactions (2018)
  • Author(s): Yutaka Watanabe
  • Organizer: 0th Northeastern Asian Symposium on “Nuclear Physics in the 21st Century”
  • Int'l Joint Research / Invited
• [Presentation] Nuclear spectroscopy of r-process nuclei using KEK Isotope Separation System (2018)
  • Author(s): Yoshikazu Hirayama
  • Organizer: The XVIII International Conference on Electromagnetic Isotope Separators and Related Topics (EMIS2018)
  • Int'l Joint Research
• [Presentation] Development of a multi-segmented proportional gas counter for b-decay spectroscopy at KISS (2018)
  • Author(s): Momo Mukai
  • Organizer: The XVIII International Conference on Electromagnetic Isotope Separators and Related Topics (EMIS2018)
  • Int'l Joint Research
• [Presentation] Production of neutron-rich nuclei by multinucleon transfer reactions at KISS project (2018)
  • Author(s): Yutaka Watanabe
  • Organizer: IX International Symposium on Exotic Nuclei
  • Int'l Joint Research / Invited
• [Presentation] Present status of KISS (2018)
  • Author(s): Yoshikazu Hirayama
  • Organizer: RIBF Users Meeting
  • Int'l Joint Research / Invited
• [Presentation] Beta-ray detector in KISS (2018)
  • Author(s): Momo Mukai
  • Organizer: The inaugural symposium of the Tomonaga Center of the History of the Universe, University of Tsukuba, Mar. 26-27, 2018
  • Int'l Joint Research / Invited
• [Presentation] KISS I : 199Ptのレーザー共鳴イオン化核分光 (2017)
  • Author(s): 平山 賀一
  • Organizer: 日本物理学会 秋季大会、宇都宮大学、2017年9月12-15日
• [Presentation] Nuclear spectroscopy of r-process nuclei around N=126 by using KISS (2017)
  • Author(s): Y. Hirayama
  • Organizer: International symposium of RI beam physics in the 21th century: 10th anniversary of RIBF, RIKEN, 4-5th December, 2017
  • Int'l Joint Research / Invited
• [Presentation] Nuclear spectroscopy of r-process nuclei around N=126 by using KISS (2017)
  • Author(s): Y. Hirayama
  • Organizer: KEK-TRIUMF Scientific Symposium, TRIUMF, 14-15th December, 2017
  • Invited
• [Presentation] Present status of the KISS project (2017)
  • Author(s): 宮武 宇也
  • Organizer: nt. WS on "Impact of Exotic Nuclear Structure on Explosive Nucleosynthesis”, Beijing Univ., Beijin China, 23-24, Nov., 2017
  • Int'l Joint Research / Invited
• [Presentation] KISS、超微細構造測定と質量測定の現状 (2017)
  • Author(s): 宮武宇也
  • Organizer: 平成29年度KUR専門研究会 「短寿命RIを用いた核分光と核物性研究」、京大原子炉実験所、１２/２０－２１
• [Presentation] Present status of the KISS project (2017)
  • Author(s): H. Miyatake
  • Organizer: International Workshop on “Physics Opportunities using CAGRA and RCNP tracking Ge detector” (CAGRA17), 10-12, Oct., Toyonaka Osaka-U.
  • Int'l Joint Research / Invited
• [Presentation] Present status of the KISS project (2017)
  • Author(s): H. Miyatake
  • Organizer: OMEG 2017, International Symposium on Origin of Matter and Evolution of Galaxies, 27-30th, June, Daejeon Korea
  • Int'l Joint Research
• [Presentation] Recent progress of the KISS project at KEK-WNSC (2017)
  • Author(s): H. Miyatake
  • Organizer: China-Japan collaboration workshop on “Nuclear mass and life for unravelling mysteries of r-process”, 26-28th, June, Univ. Tsukuba
  • Int'l Joint Research / Invited
• [Presentation] Recent KISS activities and future’s plan (2017)
  • Author(s): H. Miyatake
  • Organizer: Workshop for Einsteinium Campaign, 7-8th, Nov., 2017, Tokai, JAEA
  • Int'l Joint Research / Invited
• [Presentation] KISS II : 196-198Irのレーザー共鳴イオン化核分光 (2017)
  • Author(s): 向井 もも
  • Organizer: 日本物理学会 秋季大会、宇都宮大学、2017年9月12-15日
• [Presentation] Production of neutron-rich nuclei by multinucleon transfer reactions at KISS Project (2017)
  • Author(s): Y.X. Watanabe
  • Organizer: 3rd International Symposium on Super-Heavy Elements (SHE 2017), Kazimierz Dolny, Sep. 10-14, 2017
  • Int'l Joint Research / Invited
• [Presentation] Production of N = 126 Nuclei and Beyond Using Multinucleon Transfer Reactions for KISS Project (2017)
  • Author(s): Y.X. Watanabe
  • Organizer: ARIS2017, Keystone, May 28 - June 2, 2017
  • Int'l Joint Research
• [Presentation] Laser resonance ionization spectroscopy of 196-198Ir (2017)
  • Author(s): Momo Mukai
  • Organizer: KEK Student Day 2017, High Energy Accelerator Research Organization, Oct. 24, 2017
• [Remarks] KEK 和光原子核科学センターのホームページ
  • URL: http://research.kek.jp/group/wnsc/
• [Remarks] KEK 和光原子核科学センターのホームページ
  • URL: http://research.kek.jp/group/wnsc/
• [Remarks] KEK 和光原子核科学センター
  • URL: http://research.kek.jp/group/wnsc/