Neutron halo nuclei

1996 ◽  
Vol 22 (2) ◽  
pp. 157-198 ◽  
Author(s):  
Isao Tanihata
Keyword(s):  
Author(s):  
R.K. Biju ◽  
K. Prathapan ◽  
K.P. Anjali

The possibility for the existence of 1-neutron and 2-neutron halo nuclei through the decay of even-even nuclei 270-316116, 272-318118 and 278-320120 in the super-heavy region is studied within the frame work of the Coulomb and Proximity Potential Model (CPPM). Halo structure in neutron rich nuclei with Z<=20  is identified by calculating the neutron separation energies and on the basis of potential energy considerations. The 1n + core configuration of proposed 1-neutron halo nuclei between z=10  and Z=20 is found shifted to 2n + core configuration in higher angular momentum states. The calculation of half-life of decay is performed by considering the proposed halo nuclei as spherical cluster and as deformed nuclei with a rms radius. Except for 15C, the half-life of decay is found decreased when the rms radius is considered. Only the 1-neutron halo nuclei 26F and 55Ca showed half-lives of decay which are less than the experimental limit. None of the proposed 2-neutron halo nuclei have shown a half-life of decay lower than the experimental limit. Also, the probability for the emission of neutron halo nuclei is found to be less in super-heavy region when compared with the clusters of same isotope family. Further, neutron shell closure at neutron numbers 150, 164 and 184 is identified form the plot of  log10 T1/2 verses the neutron number of parents. The plots of Q-1/2 verses log10 T1/2 and -ln P verses log10 T1/2 for various halo nuclei emitted from the super-heavy elements are found to be linear showing that Geiger-Nuttall law is applicable to the emission of neutron halo also.


2021 ◽  
Vol 57 (5) ◽  
Author(s):  
N. Keeley ◽  
K. W. Kemper ◽  
K. Rusek

AbstractA recent comparison of the average fusion cross section, $$\left\langle \sigma _\mathrm {F}\right\rangle $$ σ F , for energies just above the Coulomb barrier for the $$^{12-15}$$ 12 - 15 C + $$^{12}$$ 12 C systems found that the behaviour as a function of projectile neutron excess could not be satisfactorily explained by static barrier penetration model calculations and suggested that the neutron dynamics plays an important rôle. In this work we demonstrate that the ($$^{15}$$ 15 C,$$^{14}$$ 14 C) single neutron transfer has a significant influence on the above barrier $$^{15}$$ 15 C + $$^{12}$$ 12 C total fusion, although not quite in the way expected since it leads to a reduction in the cross section, contrary to the trend in the measured $$\left\langle \sigma _\mathrm {F}\right\rangle $$ σ F . However, this result underlines the danger of ignoring the effect of neutron transfer reactions on fusion in systems involving neutron halo nuclei.


TCP 2010 ◽  
2011 ◽  
pp. 167-173
Author(s):  
M. Brodeur ◽  
T. Brunner ◽  
S. Ettenauer ◽  
A. T. Gallant ◽  
V. V. Simon ◽  
...  

2020 ◽  
Vol 56 (12) ◽  
Author(s):  
Pierre Capel ◽  
Ronald C. Johnson ◽  
Filomena M. Nunes

AbstractFor one-neutron halo nuclei, the cross sections for elastic scattering and breakup at intermediate energy exhibit similar angular dependences. The Recoil Excitation and Breakup (REB) model of reactions elegantly explains this feature. It also leads to the idea of a new reaction observable to study the structure of loosely-bound nuclear systems: the Ratio. This observable consists of the ratio of angular distributions for different reaction channels, viz. elastic scattering and breakup, which cancels most of the dependence on the reaction mechanism; in particular it is insensitive to the choice of optical potentials that simulate the projectile-target interaction. This new observable is very sensitive to the structure of the projectile. In this article, we review a series of previous papers, which have introduced the Ratio Method and its extension to low beam energies and proton-halo nuclei.


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