A shielding integral experiment with different thickness of slab 9Be samples based on Deuterium-Tritium neutron source

摘要: Beryllium (9Be) serves as a crucial neutron multiplier and reflection material, being extensively employed in the nuclear industry. The evaluated nuclear data are utilized in the design of the nuclear devices. Following the interaction between neutrons and 9Be, all neutrons generated stem from the 9Be(n, 2n)8Be reaction chan nel, except for the elastic scattering reaction channel. Nevertheless, the data of the outgoing neutron double differential cross section of the reaction channel provided by the latest internationally evaluated libraries still exhibit considerable discrepancies. A shielding integral experiment based on slab 9Be samples with measure ments of neutron spectra leaked from different angles is an effective approach to verify the double differential cross section data. Hence, in this study, a shielding integral experiment of 9Be samples of different thicknesses was conducted using a nanosecond pulsed deuterium-tritium neutron source established by the China Institute of Atomic Energy. Theneutron time-of-flight spectra of three thicknesses (4.4 cm, 8.8 cm, and 13.2 cm) and six an gles (47◦, 58◦, 73◦, 107◦, 122◦, and 133◦) were measured by the neutron time-of-flight method, and 18 sets of experimental data were obtained. Additionally, the MCNP-4C program was used to obtain the simulated results of the leakage neutron spectra using the evaluated nuclear data of 9Be from the CENDL-3.2, ENDF/B-VIII.0, JENDL-5, and JEFF-3.3 libraries. The simulated results of the leakage neutron spectra were compared with the experimental results, and the results showed that in the elastic scattering energy region, the simulated results from the CENDL-3.2, ENDF/B-VIII.0, and JENDL-5 libraries were slightly higher at small angles and slightly lower at large angles. In the (n, 2n) energy region, the simulated results from the CENDL-3.2 library were significantly different from the experimental results in terms of spectral shape, and the simulated results from the ENDF/B-VIII.0 and the JENDL-5 libraries were in good agreement with the experimental results at small angles but low at large angles. The simulated results from the JEFF-3.3 library showed serious underestimation at all angles.