Measurement of the 232Th(n,f) cross section with quasi-monoenergetic neutron beams in the energy range 2-18 MeV

The fission cross section of Th-232 has been measured at fast neutron energies, using a setup based on Micromegas detectors. The experiment was performed at the 5.5 MV Van de Graaff Tandem accelerator in the neutron beam facility of the National Centre for Scientific Research Demokritos. The quasi-monoenergetic neutron beams were produced via the H-3(p,n), H-2(d,n) and H-3(d,n) reactions, while the U-238(n,f) and U-235(n,f) reactions were used as references, in order to acquire cross-section data points in the energy range 2-18 MeV. The characterization of the actinide samples was performed via alpha-spectroscopy with a Silicon Surface Barrier (SSB) detector, while Monte Carlo simulations with the FLUKA code were used to achieve the deconvolution of the Th-232 alpha peak from the alpha background of its daughter nuclei present in the spectrum. Special attention was given to the study of the parasitic neutrons present in the experimental area, produced via charged particle reactions induced by the particle beam and from neutron scattering. Details on the data analysis and results are presented.

Automated summary

The fission cross section of Th-232 at fast neutron energies was measured using Micromegas detectors. Quasi-monoenergetic neutron beams were generated via specific reactions, with U-238(n,f) and U-235(n,f) as references. Actinide samples were characterized using alpha-spectroscopy with a SSB detector, and Monte Carlo simulations were utilized for data analysis.