Formation mechanism of magic numbers in unstable nuclei

• Project/Area Number: 22740150
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Single-year Grants
• Research Field: Particle/Nuclear/Cosmic ray/Astro physics
• Research Institution: The University of Tokyo
• Principal Investigator: MICHIMASA Shin'ichiro 東京大学, 大学院・理学系研究科, 助教 (80392140)
• Project Period (FY): 2010 – 2012
• Project Status: Completed (Fiscal Year 2012)
• Budget Amount: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000); Fiscal Year 2012: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000); Fiscal Year 2011: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000); Fiscal Year 2010: ¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000)
• Keywords: 原子核(実験) / 不安定核ビーム / 魔法数 / 質量測定 / 飛行時間法 / 磁気分析装置 / 不安定核

Research Abstract

We developed the method to determine nuclear masses of radioactive ions (RI’s) by coincidence measurements of magnetic rigidity and flight time in a long flight path. Those RI’s were produced by intermediate-energy fragmentation reactions from intense heavy-ion beam. CVD diamond detectors were manufactured as the fundamental detector to measure flight time. The time resolution of its detector was achieved to be 30 ps in sigma for carbon ions at 300 MeV per nucleon. A correction method in measured particle momenta was also developed by using the experimentally-determined ion-optical transfer matrix of the beam line. We demonstrated to improve the momentum resolution of the beam line form 1/3000 to 1/8100 by adopting this correction method. By those improvements, this mass measurement method was evaluated to achieve a mass resolution of several hundreds keV for the nuclei around mass number 50.

Research Products

• [Journal Article] Identification of the β ⁺ isovector spin monopole resonance via the Pb208 and Zr90(t,He3) reactions at 300MeV/u (2012)
  • Author(s): K.Miki, S.Michimasa
  • Journal Title: Physical Review Letters Volume: 108 Issue: 26 Pages: 262503-262503
  • DOI: 10.1103/physrevlett.108.262503
  • URL: https://pure.teikyo.jp/en/publications/a0566280-4006-4483-9c69-cea64149cb11
  • Peer Reviewed
• [Journal Article] Well developed deformation in 42Si (2012)
  • Author(s): S.Takeuchi, S.Michimasa
  • Journal Title: Physical Review Letters Volume: 109 Pages: 182501-5
  • Peer Reviewed
• [Journal Article] Resonance states in 27P using Coulomb dissociation and their effect on the stellar reaction (2012)
  • Author(s): Y.Togano, S.Michimasa
  • Journal Title: Physical Review C Volume: 84(035808) Pages: 7-7
  • Peer Reviewed
• [Journal Article] Well Developed Deformation in ^<42>Si (2012)
  • Author(s): S .Takeuchi
  • Journal Title: Physical Review Letters Volume: 109 Issue: 18 Pages: 109-109
  • DOI: 10.1103/physrevlett.109.182501
  • Peer Reviewed
• [Journal Article] One- and two-neutron removal reactions from 19,20C with a proton target (2011)
  • Author(s): A.Ozawa,T.Nakamura et al.
  • Journal Title: Phys.Rev.C Volume: 064315 Issue: 6 Pages: 84-84
  • DOI: 10.1103/physrevc.84.064315
  • Peer Reviewed
• [Journal Article] Nuclear reactions of 19,20C on a liquid hydrogen target measured with the superconducting TOF spectrometer (2011)
  • Author(s): T.Yamaguchi,T.Nakamura et al.
  • Journal Title: Nucl.Phys.A Volume: 1-37 Issue: 1 Pages: 864-864
  • DOI: 10.1016/j.nuclphysa.2011.05.095
  • Peer Reviewed
• [Journal Article] Resonance states in 27P using Coulomb dissociation and their effect on the stellar reaction 26Si(p,γ)27P (2011)
  • Author(s): Y. Togano, S. Kubono, 他
  • Journal Title: Phys. Rev. C Volume: 84 Issue: 3 Pages: 35808-35808
  • DOI: 10.1103/physrevc.84.035808
  • URL: https://pure.teikyo.jp/en/publications/e00c4ab3-f3b1-4db9-8faa-5cdeb5b79d43
  • Peer Reviewed
• [Journal Article] Observation of a large reaction crosssection in the drip-line nucleus 22C (2010)
  • Author(s): K.Tanaka, S.Michimasa
  • Journal Title: Physical Review Letters Volume: 104 Issue: 6 Pages: 4-4
  • DOI: 10.1103/physrevlett.104.062701
  • Peer Reviewed
• [Journal Article] Study of astrophysically important states in26Si with the p(27Si,26Si*)d reaction and the p(25Al,p)25Al elastic scattering (2010)
  • Author(s): J.Chen, S.Michimasa
  • Journal Title: Nuclear Physics A Volume: 834 Issue: 1-4 Pages: 667-669
  • DOI: 10.1016/j.nuclphysa.2010.01.119
  • Peer Reviewed
• [Journal Article] Observation of a Large Reaction Cross Section in the Drip-Line nucleus ^<22>C (2010)
  • Author(s): K.Tanaka, S.Michimasa, (23番目), 他35名
  • Journal Title: Physical Review Letters Volume: 104 Pages: 62701-62701
  • Peer Reviewed
• [Journal Article] Study of astrophysically important states in 26Si with the p(^<27>Si, ^<26>Si*)d reaction and the p(^<25>Al, p)^<25>Al elastic scattering (2010)
  • Author(s): J.Chen, S.Michimasa, (20番目), 他21名
  • Journal Title: Nuclear Physics Volume: A834
  • Peer Reviewed
• [Presentation] SHARAQ spectrometer for high-resolution studies of RI-induced reactions (2012)
  • Author(s): S.Michimasa et al. (oral),
  • Organizer: 16th International Conference on Electromagnetic Isotope Separators andTechniques Related to their Applications (EMIS2012)
  • Place of Presentation: 島根県立産業交流会館(島根県)
• [Presentation] Development of CVD diamond detector for time-of-flight measurements (2012)
  • Author(s): S.Michimasa et al. (poster)
  • Organizer: 16th International Conference on Electromagnetic Isotope Separators and Techniques Related to their Applications (EMIS2012)
  • Place of Presentation: 島根県立産業交流会館(島根県)
• [Presentation] SHARAQ spectrometer for high-resolution studies of RI-induced reactions (2012)
  • Author(s): S. Michimasa
  • Organizer: 16th International Conference on Electromagnetic Isotope Sparators and Techniques Related to their Applications (EMIS2012)
  • Place of Presentation: 島根県立産業交流会館（島根県）
• [Presentation] Development of CVD diamond detector for time-of-flight measurements (2012)
  • Author(s): S. Michimasa
  • Organizer: 16th International Conference on Electromagnetic Isotope Sparators and Techniques Related to their Applications (EMIS2012)
  • Place of Presentation: 島根県立産業交流会館（島根県）
• [Presentation] Gamma-ray spectroscopy of neutron-rich Mg isotopes by using proton inelastic scattering (2011)
  • Author(s): S.Michimasa (oral)
  • Organizer: RIBF ULIC and CNSSymposium on Frontier of Gamma-ray Spectroscopy (GAMMA11)
  • Place of Presentation: 埼玉県
  • Year and Date: 2011-06-30
• [Presentation] γ-ray spectroscopy of neutron-rich Mg isotopes by using proton inelastic scattering (2011)
  • Author(s): S.Michimasa
  • Organizer: RIBF ULIC and CNS Symposium on Frontier of Gamma-ray Spectroscopy (Gamma11)
  • Place of Presentation: 理化学研究所(埼玉県)
  • Year and Date: 2011-06-30
• [Presentation] Development of diamond detector at CNS (2011)
  • Author(s): S.Michimasa (oral)
  • Organizer: Workshop on advanced detector technology for nuclear physics
  • Place of Presentation: 埼玉県
  • Year and Date: 2011-01-12
• [Presentation] Development of Diamond detector at CNS (2011)
  • Author(s): 道正新一郎
  • Organizer: Workshop on advanced detector technology for nuclear physics
  • Place of Presentation: 理化学研究所
  • Year and Date: 2011-01-12