Differential and angle-integrated cross sections for the 10B(n, α)7Li, 10B(n, α0) 7Li and 10B(n, α1) 7Li* reactions have been measured at CSNS Back-n white neutron source. Two enriched (90%) 10B samples 5.0 cm in diameter and ~85.0 μg/cm2 in thickness each with an aluminum backing were prepared, and back-to-back mounted at the sample holder. The charged particles were detected using the silicon-detector array of the Light-charged Particle Detector Array (LPDA) system. The neutron energy En was determined by TOF (time-of-flight) method, and the valid α events were extracted from the En-Amplitude two-dimensional spectrum. With 15 silicon detectors, the differential cross sections of α-particles were measured from 19.2° to 160.8°. Fitted with the Legendre polynomial series, the (n, α) cross sections were obtained through integration. The absolute cross sections were normalized using the standard cross sections of the 10B(n, α)7Li reaction in the 0.3 − 0.5 MeV neutron energy region. The measurement neutron energy range for the 10B(n, α)7Li reaction is 1.0 eV≤En < 2.5 MeV (67 energy points), and for the 10B(n, α0) 7Li and 10B(n, α1) 7Li* reactions is 1.0 eV ≤ En < 1.0 MeV (59 energy points). The present results have been analyzed by the resonance reaction mechanism and the level structure of the 11B compound system, and compared with existing measurements and evaluations.
Considering the cosmological constant as the pressure, we mainly study the laws of thermodynamics and weak cosmic censorship conjecture in the Reissner-Nordström-AdS black hole surrounded by quintessence dark energy under charged particle absorbtion. The first law of thermodynamics is found to be valid as a particle is absorbed by the black hole. The second law however is found to be violated for the extremal and near-extremal black holes since the entropy of these black hole decrease. Moreover, we find that the extremal black hole do not change it configuration in the extended phase space, implying that the weak cosmic censorship conjecture is valid. Remarkably, the near-extremal black hole can be overcharged beyond the extremal condition under charged particle absorption. That is, the cosmic censorship conjecture could be violated for the near-extremal black hole in the extended phase space. To make a comparison, we also discuss the first law, second law as well as the weak cosmic censorship conjecture in the normal phase space, and find that all of them are valid in this case.
All existing experimental evidence of the bound state nature of the
In this work, we focused on the structure study of neutron-rich calcium isotopes, by shell model with realistic interactions. CD-Bonn and Kuo-Brown (KB) interactions are used. As they lack three-body forces, the direct use of them leads to poor calculation results. We have tested whether or not the adjustments of single particle energies (SPEs) according to single particle states would be enough to include three-body correlations empirically. It turns out that CD-Bonn interaction after the SPE-adjustment can give good agreements with data of energies and spectroscopy. For KB interaction, both SPEs and monopole terms require adjustments. Thus, the monopole problem is less serious for modern realistic interactions which include higher-order perturbations till the third order. We also test the effect of non-central force on shell structure. It is found that the effect of tensor force in CD-Bonn interaction is weaker than that in KB interaction.
In this work, we compared the effect of the isospin asymmetry of proton and neutron density distributions corresponding to the Neutron skin-type (NST) case and Hartree-Fock formalism (HF) on the half-life of alpha emitters with the atomic number in the range of
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