Fission resonances observed in the Np-237(d, pf) reaction and the fission barrier topology of Np-238

Csige, Lorant; Csatlos, Margit; Faestermann, Thomas; Habs, Dieter; Hunyadi, Matyas; Krasznahorkay, Attila J.; Thirolf, Peter G.; Tornyi, Tamas G. und Wirth, Hans-F (2022): Fission resonances observed in the Np-237(d, pf) reaction and the fission barrier topology of Np-238. In: European Physical Journal A : Hadrons and Nuclei, Bd. 58, Nr. 2, 14

Abstract

The fission probability of Np-238 was measured as a function of the excitation energy in the energy range of E* = 5.4 - 6.2 MeV in order to search for transmission fission resonances. A radioactive Np-237 target was bombarded with deuterons of Ed = 12 MeV, whereas the energy of the protons was analyzed with a superior resolution of Delta E = 8 keV. The experiment was performed at the Tandem accelerator of the Maier-Leibnitz Laboratory in Garching employing the Np-237(d,pf) reaction. A group of fission resonances has been observed at excitation energies between E* = 5.5 - 5.8 MeV, which could be ordered into three (superdeformed) rotational bands with a rotational parameter of (h) over bar (2)/2(Theta) = 3.507 keV, and identified as the first direct observation of transition states composing rotational bands in an odd-odd nucleus as they appear above the top of the outer fission barrier. Nuclear reaction code (TALYS1.95) calculations were also performed to extract the multi-humped fission barrier parameters of Np-238 by fitting them to the experimental data of the present (d,pf) and previous (n,f) experiments. The extracted barrier parameters also support the above interpretation of the observed resonances.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Physik
• Themengebiete: 500 Naturwissenschaften und Mathematik > 530 Physik
• ISSN: 1434-6001
• Sprache: Englisch