06.06.2018

Nuclear and Accelerator-Based Physics Seminars

Suggestions for speakers are most welcome! Contact Tuomas Grahn or Anu Kankainen.

Upcoming Seminars

  • June  14, 2018 at 13:15 in FYS3. Boris Andel (Comenius University, Bratislava): Laser-assisted decay studies at ISOLDE: alpha decay of 180Tl and beta-delayed fission of 188Bi

    The ISOLDE facility [1] provides one of the most intense radioactive beams in the world. In the combination with high purity of the beams it gives great possibilities to study various properties of exotic isotopes. Apart from mass separators with high resolving power, a key feature is the option to use selective laser ionization – RILIS (Resonance Ionization Laser Ion Source) [2]. With the help of RILIS, we studied two different decay modes, alpha decay of 180Tl and beta-delayed fission of 188Bi. Alpha-decay measurement is an important source of information on nuclear structure of exotic isotopes, especially when coincident γ rays are registered as well. High statistics collected during the measurement of 180Tl allowed us to analyze α-γ and α-γ-γ coincidences. We identified many new excited states in the daughter nucleus 176Au and established an extended decay scheme. Reduced α- decay widths indicated that all decays of 180Tl are hindered, which leads us to conclusion that daughter states are of different character than the ground state in 180Tl [3].

    Beta-delayed fission (βDF) allows us to investigate the fission of isotopes, which do not fission from the ground state and for which induced fission would be extremely difficult or impossible to study with current experimental facilities [4]. Previously, βDF of 188Bi was studied in JINR Dubna [5] and at SHIP (GSI Darmstadt) [6], but without a possibility to assign the fission to specific isomer of the two present in 188Bi or to deduce the total kinetic energy (TKE). In part of our experiment, we used high resolution mode of RILIS to obtain pure isomeric beams of the two isomers and thus to evaluate partial half-lives of βDF for each of them separately. Preliminary results of these investigations will be presented.

    [1] E. Kugler, Hyperfine Interact. 129, 23 (2000).
    [2] V. N. Fedoseyev et al., Hyperfine Interact. 127, 409 (2000).
    [3] B. Andel, et al., Phys. Rev. C 96, 054327 (2017).
    [4] A. N. Andreyev, M. Huyse and P. Van Duppen, Rev. Mod. Phys. 85, 1541 (2013).[5] Yu. A. Lazarev et al., Inst. Phys. Conf. Ser 132, 739 (1993).
    [6] J. F. W. Lane et al., Phys. Rev. C 87, 014318 (2013).

Past Seminars

  • April 25, 2018 at 15:15 in FYS3. Xiaofei Yang (Peking University, China): Investigating nuclear structure of exotic isotopes by laser spectroscopy 
  • April 19, 2018 at 14:15 in FYS3. Stuart Szwec (University of Jyväskylä): Probing nuclear structure using transfer reactions
  • April 13, 2018, at 13:15 in FYS3. Luca Marmugi (University College London): Ultra-cold Nuclear Matter: From Nuclear Radiuses to Collective Isomeric Decays
  • February 1, 2018, at 15:15 in FYS3. Muneer Sakildien (iThemba Labs, South Africa): An overview of the iThemba LABS facilities