Development of actinide target system for GARIS-II and its application

• Project/Area Number: 15K05116
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Particle/Nuclear/Cosmic ray/Astro physics
• Research Institution: Institute of Physical and Chemical Research
• Principal Investigator: KAJI DAIYA 国立研究開発法人理化学研究所, 仁科加速器研究センター, 仁科センター研究員 (00391912)
• Research Collaborator: MORIMOTO Kouji 国立研究開発法人理化学研究所, 仁科加速器研究センター, チームリーダー (00332247)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Project Status: Completed (Fiscal Year 2017)
• Budget Amount: ¥4,940,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥1,140,000); Fiscal Year 2017: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000); Fiscal Year 2016: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000); Fiscal Year 2015: ¥3,250,000 (Direct Cost: ¥2,500,000、Indirect Cost: ¥750,000)
• Keywords: 超重元素 / 標的 / 薄膜 / アクチノイド

Outline of Final Research Achievements

We developed gas-cooled rotating actinide-target system for gas-filled recoil ion separator GARIS-II. We developed a new sputtering system, which was installed magnetron source with 1-inch size, for preparing thick 238U metallic target. And also, we tried to optimize the conditions for preparing actinide-target using electro-deposition method. The 238U target was utilized for studying on production and decay properties of Cn (Z=112) isotopes via the reaction 48Ca+238U→286Cn* using a new gas-filled recoil ion separator GARIS-II.
A double-layered target system and an identification method (target ID) for individual targets mounted on a rotating wheel using correlation with evaporation residues were newly developed for the study of superheavy elements (SHE). The target ID method can be utilized for masking a target, measuring an excitation function without changing the beam energy from the accelerator, and searching for SHE nuclides using multiple targets during a single irradiation.

Research Products

• [Journal Article] First Direct Mass Measurements of Nuclides around Z=100 with a Multireflection Time-of-Flight Mass Spectrograph (2018)
  • Author(s): Ito Y.、Schury P.、Wada M.、Arai F.、Haba H.、Hirayama Y.、Ishizawa S.、Kaji D.、Kimura S.、Koura H.、MacCormick M.、Miyatake H.、Moon J.?Y.、Morimoto K.、Morita K.、Mukai M.、Murray I.、Niwase T.、Okada K.、Ozawa A.、Rosenbusch M.、Takamine A.、Tanaka T.、Watanabe Y.?X.、Wollnik H.、Yamaki S.
  • Journal Title: Physical Review Letters Volume: 120 Issue: 15 Pages: 152501-152501
  • DOI: 10.1103/physrevlett.120.152501
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Decay Measurement of 283Cn Produced in the 238U(48Ca,3n) Reaction Using GARIS-II (2017)
  • Author(s): Kaji Daiya、Morimoto Kouji、Haba Hiromitsu、Wakabayashi Yasuo、Takeyama Mirei、Yamaki Sayaka、Komori Yukiko、Yanou Shinya、Goto Shin-ichi、Morita Kosuke
  • Journal Title: Journal of the Physical Society of Japan Volume: 86 Issue: 8 Pages: 085001-085001
  • DOI: 10.7566/jpsj.86.085001
  • Peer Reviewed
• [Journal Article] First online multi reflection time-of-flight mass measurements of isobaric chains produced by fusion-evaporation reactions: Toward identification of superheavy elements via mass spectroscopy (2017)
  • Author(s): P.Schury, M.Wada, Y.Ito, D.Kaji, F.Arai, M.MacCormick, I.Murray, H.Haba, S.Jeong, S.Kimura, H.Koura, H.Miyatake, K.Morimoto, K.Morita, A.Ozawa, M. Reponen, P-A.Soederstroem, A.Takamine, T.Tanaka, H.Wollnik
  • Journal Title: Physical Review C Volume: 95 Issue: 1 Pages: 011305-011305
  • DOI: 10.1103/physrevc.95.011305
  • NAID: 120006502093
  • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] Study of the reaction 48Ca + 248Cm → 296Lv* at RIKEN-GARIS (2017)
  • Author(s): D. Kaji, K. Morita, K. Morimoto, H. Haba, M. Asai, K. Fujita, Z. Gan, H. Geissel, H. Hasebe, S. Hofmann, M. Huang, Y. Komori, L. Ma, J. Maurer, M. Murakami, M. Takeyama, F. Tokanai, T. Tanaka, Y. Wakabayashi, T. Yamaguchi, S. Yamaki, and A. Yoshida
  • Journal Title: J. Phys. Soc. Jpn. Volume: 86 Issue: 3 Pages: 034201-034201
  • DOI: 10.7566/jpsj.86.034201
  • NAID: 210000134293
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Decay Properties of New Isotopes 234Bk and 230Am, and Even-Even Nuclides 234Cm and 230Pu (2016)
  • Author(s): D. Kaji et al
  • Journal Title: J. Phys. Soc. of Jpn. Volume: 85 Issue: 1 Pages: 0150021-2
  • DOI: 10.7566/jpsj.85.015002
  • NAID: 210000133812
  • Peer Reviewed
• [Journal Article] Detector Calibration to Spontaneous Fission for the Study of Superheavy Elements Using Gas-Filled Recoil Ion Separator (2016)
  • Author(s): M. Takeyama, D. Kaji et al.
  • Journal Title: JPS Conf. Proc. Volume: 11 Pages: 0300041-6
  • DOI: 10.7566/jpscp.11.030004
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Double-layered target and identification method of individual target correlated with evaporation residues (2015)
  • Author(s): D. Kaji and K. Morimoto
  • Journal Title: Nuclear Instruments and Methods in Physics Research Section A 792, p.11 (2015). Volume: 792 Pages: 11-14
  • DOI: 10.1016/j.nima.2015.04.042
  • Peer Reviewed / Open Access / Acknowledgement Compliant
• [Presentation] Hot fusion study using a new separator GARIS-II (2017)
  • Author(s): D. Kaji
  • Organizer: SHE2017
  • Int'l Joint Research
• [Presentation] スパッタ法による厚い金属ウラン標的の調整と照射試験 (2017)
  • Author(s): 加治大哉
  • Organizer: 第60回放射化学討論会
• [Presentation] GARIS-II を用いたホットフュージョン反48Ca+238U→286Cn*に関する研究 (2016)
  • Author(s): 加治大哉
  • Organizer: 第60回放射化学討論会
  • Place of Presentation: 新潟大学（新潟県新潟市）
  • Year and Date: 2016-09-10
• [Presentation] GARIS を用いた超重元素研究の最前線 ―新元素認定までの道のり、周期表の拡張を目指した挑戦― (2016)
  • Author(s): 加治大哉
  • Organizer: 第60回放射化学討論会
  • Place of Presentation: 新潟大学（新潟県新潟市）
  • Year and Date: 2016-09-10
  • Invited
• [Presentation] Heavy element study using a new separator GARIS-II (2015)
  • Author(s): D. Kaji
  • Organizer: Pacifichem 2015
  • Place of Presentation: Honolulu, Hawaii, USA
  • Year and Date: 2015-12-15
  • Int'l Joint Research
• [Presentation] GARIS-II: New Gas-filled Recoil Ion Separator at RIKEN (2015)
  • Author(s): D. Kaji
  • Organizer: The 5th International Conference on the Chemistry and Physics of the Trasactinide Elements
  • Place of Presentation: Urabandai Royal hotel, Fukushima, Japan
  • Year and Date: 2015-05-25
  • Int'l Joint Research
• [Remarks] 新元素探索へ向けて気体充填型反跳分離器GARIS-Ⅱが本格始動
  • URL: http://www.riken.jp/pr/press/2017/20170721_2/
• [Remarks] 新元素探索へ向けて気体充填型反跳分離器GARIS-Ⅱが本格始動
  • URL: http://www.nishina.riken.go.jp/news/2017/20170721.html
• [Remarks] メンデレビウム同位体を始め6個の超ウラン元素同位体の直接質量測定に初めて成功
  • URL: https://www.kek.jp/ja/newsroom/2018/03/29/1000/
• [Remarks] メンデレビウム同位体を始め6個の超ウラン元素同位体の直接質量測定に初めて成功
  • URL: http://www.riken.jp/pr/press/2018/20180329_1/