18.12.2018

Nuclear and Accelerator-Based Physics Seminars

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

Upcoming Seminars

  • January 22, 2019 at 9:15 in FYS3. Sasha Zadvornaya (JYFL)
    title TBA
    abstract TBA 

Past Seminars

  • December 12, 2018 at 14:15 in FYS3. Ronald Fernando Garcia Ruiz (ISOLDE, CERN)
    Shedding light on quantum many-body problems
    Atomic and molecular structures can be sensitive to observables that are key for our understanding of the nuclear many-body problem, the study of fundamental symmetries, and the search of new physics. This seminar will present recent results from precision laser spectroscopy experiments of exotic atoms and molecules at ISOLDE-CERN. The relevance of these results and their connection with the recent advances in nuclear, atomic and quantum chemistry theory will be discussed.
  • December 10, 2018 at 14:15 in FYS3. Simon Giraud (GANIL and LPC Caen)
    Study of core-collapse supernovae: nuclear physics inputs for a new NSE modeling
    The nuclear equation of state (EoS) and the electron-capture rates are among the main nuclear physics inputs used in core-collapse supernovae modeling. For these inputs, it is essential to know as precise as possible the nuclear masses because the distribution of populated microstates strongly depends on them. In addition, the values of nuclear masses enter directly in the calculations of the electron-capture rates, that, in turn, impact the neutrino flux which carries out 99% of the energy of the explosion.
    A recent sensitivity study, carried out by Sullivan et al. [1], pointed out that the nuclei playing the most important role during the core-collapse phase are located around 78Ni and 128Pd, which are at the N=50 and N=82 shell closures. More recently, using a new perturbative treatment of the extended Nuclear Statistical Equilibrium (NSE) model, we have shown that, along the collapse trajectory, nuclei seem indeed to concentrate around magic numbers. To this aim, we have applied the new approach to the Lattimer and Swesty (LS) EoS, considering a fixed representative core-collapse trajectory [2].
    The knowledge of the gap values for this nuclei of interest is thus essential. However, they rely on model predictions that may differ substantially. An experiment, that aimed to measure new nuclear masses and to improve those known around 78Ni using the JYFLTRAP Penning trap mass spectrometer at the IGISOL facility has been performed last year. The results obtained show that, the HFB-24 mass model is the one which reproduces better the experimental mass data and the N=40,50 and Z=28 gaps evolution far from stability, compared to the widely used DZ10 model. Therefore, they confirm the validity of the HFB-24 mass model far from stability and allow us to put more constraints on the neutron (N=40,50) and proton (Z=28) gap energies. Besides, new isomeric states have been also measured which could be of great interest for nuclear structure studies. Comparison with results obtained from shell model calculations using recent interactions is ongoing. Implementing consistently the new NSE-based model described above into a collapse numerical simulation, we will be able to quantify the impact of the shell effects based on our recent experimental results on the nuclear composition of the collapsing core.
    [1] C. Sullivan et al., ApJ 816, 44 (2016)
    [2] G. Grams, S. Giraud, A. F. Fantina, F. Gulminelli, PRC 97, 035807 (2018)
     
  • November 28, 2018 at 9:15 in FYS3. Julia Even (KVI-CART, University of Groningen) 
    What is NEXT? - Neutron-rich EXotic nuclei produced in multinucleon Transfer reactions. 
    Multi-nucleon transfer reactions using actinide targets hold the potential for the discovery of new isotopes in the transfermium region. These will provide access to information on the evolution of nuclear shell structure and fission half-lives in the heavy element region. Due to the large angular distribution of the transfer products, sample preparation for mass measurements and decay spectroscopy studies remains challenging a. So far, no separator dedicated to the production of heavy elements with multi-nucleon transfer reaction has been build.
    In the NEXT project, a solenoid spectrometer will be combined with a Multi Reflection-Time of Flight Mass Spectrometer (MR-ToF MS) in order to overcome experimental limitations. The solenoid spectrometer provides a large angular acceptance for transfer products. With help of the MR-ToF MS masses in the region around mendelevium towards the subneutron shell closure N=162 will be accessible. Furthermore the evolution of fission half-lives will be studied.
    In my presentation, I will present my NEXT project for which I recently received an ERC starting grant. 
  • November 27, 2018 at 9:15 in FYS3. Olga Beliuskina (JYFL)
    On the synthesis of neutron-rich isotopes along the N=126 shell in multinucleon transfer reactions
    We performed experimental and theoretical studies of deep inelastic multinucleon transfer reactions in heavy-ion collisions at Coulomb barrier energies. The goal was to investigate if deep inelastic transfer is superior to fragmentation reactions for producing neutron-rich isotopes in the astrophysically interesting region along the closed neutron shell N = 126. The experiment was performed at the velocity filter SHIP at GSI Darmstadt. Several transfer products on the neutron-rich side were populated but new isotopes were not observed. A comparison of the measured transfer cross-sections and production yields with those from fragmentation reactions allowed for interesting conclusions.
  • November 22, 2018 at 9:15 in FYS3. Bahadir Sayği (Ege University), Pseudo-mirror nuclei in the mass regions varying from A ~ 100 to A ~ 200.
  • November 20, 2018 at 9:15 in FYS3. Alexander Karpov (JINR, Dubna), How to produce neutron-rich heavy nuclei?
  • October 16, 2018 at 14:15 in FYS3. Khuyagbaatar Jadambaa (GSI Helmholtzzentrum für Schwerionenforschung & Helmholtz-Institut Mainz), β(EC) delayed fission in the heaviest nuclei
  • October 10, 2018 at 13:15 in FYS3. Frank Wienholtz (CERN), Lessons learned from the success of ISOLTRAP’s MR-TOF and a possible future 30-kV ISOLDE device
  • 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
  • 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