NUCLEAR LEVEL DENSITY AT FINITE TEMPERATURES

2006 ◽  
Vol 15 (02) ◽  
pp. 478-483 ◽  
Author(s):  
J. BARTEL ◽  
K. POMORSKI ◽  
B. NERLO-POMORSKA

Selfconsistent mean-field calculations have been performed with the SkM* Skyrme force for 140 spherical even-even nuclei at temperatures 0≤T≤4 MeV . Single-particle level densities for this sample of nuclei are determined for various temperatures. The average dependence of the single-particle level density on mass number A and isospin is given and compared with previous estimates obtained using the relativistic mean-field and different semiclassical approaches.

2004 ◽  
Vol 13 (06) ◽  
pp. 1147-1155 ◽  
Author(s):  
BOŻENA NERLO-POMORSKA ◽  
KRZYSZTOF POMORSKI ◽  
JOANNA SYKUT ◽  
JOHAN BARTEL

A new set of relativistic mean-field theory (RMFT) parameters, NL4, ensuring a better description of the average nuclear energy as given by the new Lublin–Strasbourg mass formula, is used in a self-consistent description of 171 spherical even-even nuclei at temperatures 0≤T≤4 MeV. Single-particle level densities for this sample of nuclei are determined by analyzing the data obtained for various temperatures. The average dependence of the single-particle level density on mass number A and isospin is given and compared with previous estimates obtained using the RMFT-NL3, Thomas–Fermi and semiclassical Skyrme SkM* approaches.


2005 ◽  
Vol 14 (03) ◽  
pp. 505-511 ◽  
Author(s):  
B. NERLO-POMORSKA ◽  
K. POMORSKI ◽  
J. SYKUT ◽  
J. BARTEL

Self-consistent relativistic mean-field (RMF) calculations with the NL3 parameter set were performed for 171 spherical even-even nuclei with 16≤A≤224 at temperatures in the range 0≤T≤4 MeV . For this sample of nuclei single-particle level densities are determined by analyzing the data obtained for various temperatures. A new shell-correction method is used to evaluate shell effects at all temperatures. The single-particle level density is expressed as function of mass number A and relative isospin I and compared with previous estimates.


2016 ◽  
Vol 31 (37) ◽  
pp. 1650211
Author(s):  
S. A. Alavi ◽  
V. Dehghani

By using semiclassical method and considering deformed Woods–Saxon mean field potential, single-particle level density g, level density parameter a, and nuclear level density have been calculated for some deformed nuclei with deformation parameters ([Formula: see text], [Formula: see text]). Significant difference between deformed and spherical level density parameter and nuclear level density were observed. The effect of [Formula: see text] on level density parameter was notable. A simple formula for single-particle level density has been introduced.


2014 ◽  
Vol 29 (03) ◽  
pp. 1450017 ◽  
Author(s):  
M. R. PAHLAVANI ◽  
S. A. ALAVI ◽  
E. FARHADI

The nuclear level density parameters of back shift Fermi gas model, including single-particle level density parameter a and excitation energy shift E1, for some heavy nuclei have been calculated in the framework of semiclassical approach. The single-particle level density have been obtained for mean-field Woods–Saxon potential. By using the obtained values of single-particle level density parameter and excitation energy shift, the spin cut-off factor has been calculated at the neutron binding energy.


2007 ◽  
Vol 16 (02) ◽  
pp. 566-569 ◽  
Author(s):  
KRZYSZTOF POMORSKI ◽  
BOŻENA NERLO-POMORSKA ◽  
JOHANN BARTEL

The average dependence of the single-particle level-density parameter on mass number A, isospin and deformation is determined using the Yukawa folded mean-field potential for spherical and deformed nuclei at temperatures 0 ≤ T ≤ 5 MeV and elongations ranging from oblate shapes to the scission configuration of fissioning nuclei. The results are compared with similar estimates obtained previously using the relativistic mean-field theory, the Skyrme Hartree-Fock and the Thomas-Fermi approach.


2009 ◽  
Vol 24 (2) ◽  
pp. 82-85 ◽  
Author(s):  
Aziz Behkami ◽  
Rohallah Razavi ◽  
Tayeb Kakavand

The excited states of 73As have been investigated via the 73Ge(p, n?)73As reaction with the proton beam energies from 2.5-4.3 MeV. The parameters of the nuclear level density formula have been determined from the extensive and complete level scheme for 73As. The Bethe formula for the back-shifted Fermi gas model and the constant temperature model are compared with the experimental level densities.


1979 ◽  
Vol 26 (16) ◽  
pp. 519-524 ◽  
Author(s):  
H. Majumdar ◽  
A. Chatteejee

Author(s):  
C. Kokila ◽  
C. Karthika ◽  
M. Balasubramaniam

Ternary decay is comparatively a rare phenomenon. The yield distribution for the thermal neutroninduced fission of 236U was investigated within the Temperature-dependent Relativistic Mean Field (TRMF) approach and statistical theory. Binding energy obtained from TRMF for the ground state and at a specific temperature is used to evaluate the fragment excitation energy, which is needed to calculate the nuclear level density. Using the ternary convolution, the yield for α-accompanied fission of 236U* is calculated. Initial results are presented which shows a maximum yield for the fragment pair Tc + Ag +α. Further, the ternary pre-existence probability for the spontaneous fission of 236U was studied considering fixed third fragments of α,10Be and 14C using the area of the overlapping region. No significant change in the yield distribution was observed when fragment deformations are considered. However, the heavy group for the probable pair remains as 132Sn with a change in mass number of the lighter fragment. 


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