Bonn 2020 – wissenschaftliches Programm
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HK 17.5: Vortrag
Dienstag, 31. März 2020, 18:15–18:30, J-HS E
Low-energy dipole response of the halo nuclei 6,8He — •Christopher Lehr1 and Thomas Aumann1,2 for the NeuLAND-SAMURAI collaboration — 1TU Darmstadt — 2GSI Helmholtzzentrum
The heaviest bound helium isotopes 6He and 8He are 2- and 4-neutron halo nuclei with a clear alpha plus 2n and 4n structure.
The multi-neutron decay of 6He and 8He after heavy-ion induced electromagnetic excitation reactions has been measured kinematically complete to study the dipole response of these nuclei. The combination of the neutron detectors NEBULA and NeuLAND at the SAMURAI setup and the high beam intensities available at the RIKEN Nishina Center in Japan made this measurement possible for the first time. The experimental method is based on the measurement of the differential cross section via the invariant-mass method, which allows to extract the dipole strength distribution dB(E1)/dE and the photo-absorption cross section.
The analysis of the data is nearly finished and the neutron reconstruction and cross talk analysis for the challenging 4-neutron channel, in which good statistics could still be achieved, has been performed. During the talk preliminary results focusing on the 6He and 8He excitation energy spectra and the dipole strength distributions will be presented and discussed.
This work is supported by the DFG through grant no. SFB 1245, the GSI-TU Darmstadt cooperation and the BMBF project 05P15RDFN1.