PROTON DRIPLINE FOR ISOTONE N = 18, 20, AND 22 USING MODIFIED RELATIVISTIC MEAN FIELD (MRMF) MODEL

Determining the position of one- and two-proton dripline for isotone of N = 18, 20, and 22 has been studied through Modified Relativistic Mean Field (MRMF). The model exemplifies three impacts, namely isovector-isoscalar coupling, tensors, and electromagnetic exchange through five parameter set variations. The position of one- and two-proton dripline for the isotones is predicted by applying two methods, which are two-proton separation energy, and Fermi energy. The research shows that the prediction of one- and two-proton dripline for isotone of N = 18, and N = 20 is positioned at Z = 22 and Z = 26 consecutively. Then, the prediction of one- and two-proton dripline for isotone of N = 22 has two positions, Z = 26 and Z = 28. The calculation result indicates that the position prediction for isotone of N = 18, N = 20, and N = 22 is following the research result conducted by Nazarewicz with RMF+NLSH model [1]. Meanwhile, isovector-isoscalar coupling, tensors, and electromagnetic exchange do not affect massively for the position prediction of two-proton dripline. However, the three methods affect one-proton dripline.

New investigations on the 32S(3He,d)33Cl reaction at 9.6 MeV bombarding energy

The 32S(3He,d)33Cl one-proton transfer reaction is a powerful tool to investigate the spectroscopy of low-lying states in the proton-rich 33Cl nucleus. However, the extraction of firm differential cross-section data at various angles to benchmark and constrain theoretical models is made challenging by the presence of competitive reactions on target contaminants. In this paper we report on arecent measurement using a new generation hodoscope of silicon detectors, capable to detect and identify emitted deuterons down to energies of the order of 2 MeV. The high angular segmentation of our hodoscope combined with a suitable target to control possible contaminants, allowed to unambiguously disentangle the contribution of various states in 33Cl, in particular the 2.352 MeV state lying just few tens of keV above the proton separation energy.

Systematics of (n,p) reaction cross-sections for light element target nuclei at 14.5MeV neutrons

The systematics of neutron-induced reactions at 14.5[Formula: see text]MeV are of great importance to describe the excitation of nuclei for the [Formula: see text] reactions. In this study, a new empirical formula is obtained by introducing the proton separation energy to the principal empirical formula for estimating the [Formula: see text] reaction cross-sections for 77 nuclei in the light element mass number range [Formula: see text] at the incident neutron energy of 14.5[Formula: see text]MeV. The calculated results are compared with the evaluated data declared by the TENDL nuclear data library. The predictions of our formula reveal better agreement with the experimental data than the results obtained from the previous suggested formulae.

STUDY OF TWO-PROTON RADIOACTIVITY WITHIN THE RELATIVISTIC MEAN-FIELD PLUS BCS APPROACH

Inspired by recent experimental studies of two-proton radioactivity in the light-medium mass region, we have employed relativistic mean-field plus state-dependent BCS approach (RMF+BCS) to study the ground state properties of selected even-Z nuclei in the region 20 ≤ Z ≤ 40. It is found that the effective potential barrier provided by the Coulomb interaction and that due to centrifugal force may cause a long delay in the decay of some of the nuclei even with small negative proton separation energy. This may cause the existence of proton-rich nuclei beyond the proton drip-line. Nuclei 38 Ti , 42 Cr , 45 Fe , 48 Ni , 55 Zn , 60 Ge , 63, 64 Se , 68 Kr , 72 Sr and 76 Zr are found to be the potential candidates for exhibiting two-proton radioactivity in the region 20 ≤ Z ≤ 40. The reliability of these predictions is further strengthened by the agreement of the calculated results for the ground state properties such as binding energy, one- and two-proton separation energy, proton and neutron radii, and deformation with the available experimental data for the entire chain of the isotopes of the nuclei in the region 20 ≤ Z ≤ 40.

PARTICLE-NUMBER PROJECTED TWO-PROTON SEPARATION ENERGY OF THE PROTON-RICH EVEN–EVEN RARE-EARTH NUCLEI USING AN ISOVECTOR PAIRING APPROACH

The two-proton separation energy (S2P) has been studied by describing the pairing correlations using four various approaches: in the pairing between like-particles case with (SBCS) and without (BCS) inclusion of the particle-number projection, as well as in the isovector pairing case with (NP-PROJ) and without (NP) inclusion of the particle-number projection. It has been numerically evaluated for the even–even rare-earth proton-rich nuclei such as Δnp ≠ 0. Among the four used methods, NP-PROJ is the one that provides the results that are closest to the experimental data when available. On the other hand, it has been shown that the S2P values deduced from the four approaches join, for almost all the considered elements, for the highest values of (N - Z). The fact that the BCS and NP (respectively, SBCS and NP-PROJ) values join may be explained by the fact that Δnp decreases with increasing values of (N - Z). It has also been shown that the BCS and SBCS (respectively, NP and NP-PROJ) values of S2P are very close because the discrepancy between the projected and unprojected energy values is quasi-constant as a function of the deformation. Finally, the four used methods lead to the same prediction of the two-proton drip-line position except for the Dysprosium and the Tungsten.

Proton Separation Energies for Some Rare Earth Isotopes

Reaction Q values for the (3He,d) and (α,t) single proton transfer reactions on targets of Gd, Dy, Er, and Yb have been measured with a magnetic spectrograph. Proton separation energies, Sp, are presented for 156,157,158,159,161Tb, 161,162,163,164,165Ho, 165,167,168,169,171Tm, and 171,172,173,174,175,177Lu. Although the uncertainties of the absolute Q values are approximately 15 keV, the use of isotopically mixed and natural targets resulted in probable errors of only 1–3 keV for the differences in Q values of the isotopes identified in each target. As the proton separation energy was previously known to within 1–3 keV for one isotope of each element studied, it is now possible to present SP values with errors of a few keV for ail the nuclides listed above.