THE FISSION BARRIERS OF HEAVY AND EXOTIC NUCLEI

2010 ◽  
Vol 19 (04) ◽  
pp. 514-520 ◽  
Author(s):  
FEDIR IVANYUK ◽  
KRZYSZTOF POMORSKI
Keyword(s):  
Liquid Drop ◽  
Optimal Shape ◽  
Exotic Nuclei ◽  
Fission Barrier ◽  
Heavy Nuclei ◽  
Accurate Approximation ◽  
Barrier Heights ◽  
A Value ◽  
Fission Barriers ◽  
Experimental Values

We have calculated the liquid drop fission barriers of medium and heavy nuclei within the Lublin-Strasbourg-Drop model. Exploiting in addition the topographical theorem by Myers and Światecki we propose a simple but quite accurate approximation of the fission barrier heights. When comparing the r.m.s. deviation of approximated versus experimental values of fission barrier heights for known nuclei with Z > 70 a value 1.1 MeV is obtained which is comparable with the experimental uncertainties. The Strutinsky optimal shape method is generalized to the left-right asymmetric shapes of nuclei in order to investigate the influence of this degree of freedom on the barrier heights.

scholarly journals FURTHER MICROSCOPIC STUDIES OF THE FISSION BARRIERS OF HEAVY NUCLEI

2012 ◽  
Vol 21 (05) ◽  
pp. 1250051 ◽  
Author(s):  
T. V. NHAN HAO ◽  
J. LE BLOAS ◽  
MENG-HOCK KOH ◽  
L. BONNEAU ◽  
P. QUENTIN
Keyword(s):  
Spontaneous Fission ◽  
The Self ◽  
Fission Barrier ◽  
Heavy Nuclei ◽  
Barrier Heights ◽  
Fission Barriers ◽  
Self Consistent ◽  
Microscopic Studies ◽  
Mean Fields ◽  
Approximate Treatment

Two systematic sources of error in most current microscopic evaluations of fission-barrier heights are studied. They are concerned with an approximate treatment of the Coulomb exchange terms (known as the Slater approximation) in the self-consistent mean-fields and the projection on good parity states (e.g., of positive parity for the spontaneous fission of an even–even nucleus) of left–right reflection asymmetric intrinsic solutions (e.g., around the second barrier). Approximate or unprojected solutions are shown to lead each to an underestimation of the barrier heights by a few hundred keV.

FISSION BARRIERS WITHIN THE LIQUID DROP MODEL WITH THE SURFACE-CURVATURE TERM

2004 ◽  
Vol 13 (01) ◽  
pp. 107-112 ◽  
Author(s):  
K. POMORSKI ◽  
J. DUDEK
Keyword(s):  
Liquid Drop ◽  
Surface Curvature ◽  
Fission Barrier ◽  
Macroscopic Model ◽  
Liquid Drop Model ◽  
Barrier Heights ◽  
Curvature Term ◽  
Fission Barriers ◽  
The Masses ◽  
Weak Influence

The recently revised liquid drop model (PRC 67(2003) 044316) containing the curvature term reproduces the masses of 2766 experimentally known isotopes having Z≥8 and N≥8 with the r.m.s. deviation equal to 0.698 MeV when the microscopic corrections of Moeller et al. is used. The influence of the congruence energy as well as the compression term on the barrier heights is discussed within this new macroscopic model. The r.m.s. deviation of the fission barrier heights of 40 isotopes with Z≥34 is 1.73 MeV only when deformation-dependent congruence energy is included. The effect of the compression term in the liquid drop energy has rather weak influence on the barrier heights.

scholarly journals Direct measurement of fission barrier height of unstable heavy nuclei at ISOL facilities

2019 ◽  
Vol 26 ◽  
pp. 51
Author(s):  
M. Veselský ◽  
J. Klimo ◽  
R. Raabe ◽  
A. N. Andreyev ◽  
M. Huyse ◽  
...  
Keyword(s):  
Barrier Height ◽  
Experimental Studies ◽  
Fission Barrier ◽  
Heavy Nuclei ◽  
Radioactive Beams ◽  
Active Target ◽  
Barrier Heights ◽  
Fission Barriers ◽  
New Generation ◽  
Stability Line

Fission barrier height is one of the least known nuclear parameters, with experimental data, acquired decades ago, existing only close to beta-stability line. Availability of heavy radioactive beams offers possibility to investigate fission of more exotic nuclei and using the state of the art detection technique such as the active target we can even probe their fission barriers heights with precision has not been reached so far. The present status of fission barrier measurement is going to be explained in this paper. We are going to discuss the possibilities to stage experimental studies of fission barrier heights at new generation of ISOL facilities such as HIE-ISOLDE and active target ACTAR TPC. As an example we select the experiment IS581, being prepared for execution at the HIE-ISOLDE facility (CERN).

scholarly journals Fusion and fission barrier heights and positions within the Generalized Liquid Drop Model

2021 ◽  
Vol 1010 ◽  
pp. 122191
Author(s):  
G. Royer ◽  
M. Guillot ◽  
J. Monard
Keyword(s):  
Liquid Drop ◽  
Fission Barrier ◽  
Liquid Drop Model ◽  
Barrier Heights

Fission-barrier heights in some newest liquid-drop models

2013 ◽  
Vol T154 ◽  
pp. 014023 ◽  
Author(s):  
Krzysztof Pomorski
Keyword(s):  
Liquid Drop ◽  
Fission Barrier ◽  
Barrier Heights

DESCRIPTION OF EXPERIMENTAL FISSION BARRIERS OF HEAVY NUCLEI

2009 ◽  
Vol 18 (04) ◽  
pp. 869-872 ◽  
Author(s):  
A. SOBICZEWSKI ◽  
M. KOWAL
Keyword(s):  
Heavy Nuclei ◽  
Fission Barriers ◽  
Experimental Values

The accuracy of the description of the experimental heights of the fission barriers of heavy nuclei is studied. Four theoretical descriptions are considered. It is found that the average discrepancy between theoretical and experimental values for 18 even-even nuclei is about 0.8 MeV, while the largest discrepancy is about 2 MeV.

IMPORTANCE OF MASS ASYMMETRY AND NONAXIALITY FOR THE DESCRIPTION OF FISSION BARRIERS

2006 ◽  
Vol 15 (02) ◽  
pp. 432-436 ◽  
Author(s):  
ARTUR DOBROWOLSKI ◽  
KRZYSZTOF POMORSKI ◽  
JOHANN BARTEL
Keyword(s):  
Substantial Effect ◽  
Fission Barrier ◽  
Microscopic Model ◽  
Mass Asymmetry ◽  
Barrier Heights ◽  
Fission Barriers

In the framework of the macroscopic-microscopic model fission barriers in the region of actinide nuclei are investigated. Taking left-right mass asymmetric and non-axial shapes into account is demonstrated to have a substantial effect on fission barrier heights.

ESTIMATION OF THE INACCURACY OF CALCULATED MASSES AND FISSION-BARRIER HEIGHTS OF HEAVY NUCLEI

2011 ◽  
Vol 20 (02) ◽  
pp. 325-332 ◽  
Author(s):  
A. SOBICZEWSKI ◽  
P. ROZMEJ
Keyword(s):  
Heavy Nucleus ◽  
Ground State ◽  
Interaction Strength ◽  
Fission Barrier ◽  
Heavy Nuclei ◽  
Pairing Interaction ◽  
Microscopic Approach ◽  
Barrier Heights ◽  
Pairing Strength ◽  
Microscopic Models

The inaccuracy of calculated masses M and (static) fission-barrier height [Formula: see text] of heaviest nuclei is estimated. The estimation is performed within a macroscopic-microscopic approach for two nuclei: a heavy nucleus 250 Cf and a superheavy one 294118. The source of the inaccuracy is the inaccuracy of calculated deformation of a nucleus and of calculated pairing-interaction strength. It is shown that the inaccuracy of the ground-state mass M, due to the inaccuracy of the calculated deformation is small, up to about 20 keV. The inaccuracy of M, due to the inaccuracy of the pairing strength is much larger, up to 310 keV. The inaccuracy of [Formula: see text], due to the inaccuracy of the deformation is up to about 70 keV, while this due to the inaccuracy of the pairing strength is up to 520 keV. For both studied nuclei, the calculated inaccuracy of [Formula: see text] is smaller than the discrepancy between the values of [Formula: see text] obtained recently within different macroscopic-microscopic models.

scholarly journals Fusion probability of massive nuclei in reactions leading to heavy composite nuclear systems

2019 ◽  
Vol 223 ◽  
pp. 01052
Author(s):  
Roman Sagaidak
Keyword(s):  
Statistical Model ◽  
Cross Sections ◽  
High Probability ◽  
Heavy Nuclei ◽  
Fission Barriers ◽  
Nuclear Systems ◽  
Fusion Probability ◽  
Experimental Values ◽  
Evaporation Residues ◽  
Bp Model

Reactions between massive nuclei show a considerable reduction in fusion-evaporation cross-sections at the Coulomb barrier according to the comparison of experimental values with those calculated by barrier passing (BP) and statistical model (SM) approximations. Reduced fusion cross-sections corresponding to fusion probability PCN<1 are accompanied by a high probability of deep-inelastic and quasi-fission processes arising on the way to fusion. At the same time, the excitation functions for evaporation residues (ERs) obtained in very mass-asymmetric projectile-target combinations are well described in the framework of the BP model (assuming PCN=1) and SM approximations. In the framework of SM, the survivability of produced heavy nuclei can be described with the use of adjusted macroscopic fission barriers. Fusion suppression appears in less asymmetric combinations, for which PCN values can be estimated using survivability obtained for very asymmetric ones leading to the same CN. An attempt was made to systemize the PCN data derived from different projectile-target combinations leading to ERs in the range from Pb to the most heavies, which are compared withPCN values obtained in fission experiments.

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