Fusion-Evaporation Cross Sections in Reactions Leading to Production of Super-Heavy Nuclei

2006 ◽  
Author(s):  
K. Siwek-Wilczyńska
Keyword(s):  
Cross Sections ◽  
Heavy Nuclei ◽  
Super Heavy Nuclei

CALCULATIONS OF CROSS SECTIONS FOR THE SYNTHESIS OF SUPER-HEAVY NUCLEI IN COLD FUSION REACTIONS

2004 ◽  
Vol 13 (01) ◽  
pp. 261-267 ◽  
Author(s):  
W. J. ŚWIATECKI ◽  
K. SIWEK-WILCZYŃSKA ◽  
J. WILCZYŃSKI
Keyword(s):  
Cross Section ◽  
Compound Nucleus ◽  
Cross Sections ◽  
Free Parameter ◽  
Cold Fusion ◽  
One Dimension ◽  
Brownian Diffusion ◽  
Heavy Nuclei ◽  
Fusion Reactions ◽  
Super Heavy Nuclei

The fusion cross sections are considered to be given by the product of three factors: the cross section to overcome the Coulomb barrier, the probability for the resulting system to reach the compound nucleus configuration by diffusion, and the probability for the compound nucleus to survive fission. The first and third factors are treated by more or less conventional equations, and the second by Brownian diffusion in one dimension. Adjusting one free parameter in the theory one can reproduce the twelve measured cross sections to within a factor of two.

THE ISOTOPIC AND NUCLEAR ORIENTATION EFFECTS ON THE PRODUCTION OF SUPER-HEAVY ELEMENTS

2008 ◽  
Vol 17 (09) ◽  
pp. 1937-1944 ◽  
Author(s):  
E. G. ZHAO ◽  
N. WANG ◽  
Z. Q. FENG ◽  
J. Q. LI ◽  
S. G. ZHOU ◽  
...  
Keyword(s):  
Cross Sections ◽  
Nuclear Orientation ◽  
Neutron Number ◽  
Evaporation Residue ◽  
System Model ◽  
Heavy Nuclei ◽  
Nuclear System ◽  
Isotopic Dependence ◽  
Super Heavy Nuclei ◽  
Evaporation Residue Cross Section

Based on a modified di-nuclear system model in which the nucleon transfer is coupled with the dissipation of energy and angular momentum, the isotopic dependence and the orientation (between the target and the projectile) effects on the evaporation residue cross section for synthesizing super-heavy nuclei are investigated. The calculated results indicate that the cross sections shows an odd-even effect and does not change much with increasing neutron number of the target. The influences of deformation and relative orientation of the projectile and target are also discussed. Our results show that the waist to waist orientation is in favor of the formation of super-heavy compound nuclei.

scholarly journals The driving potential and cross sections for synthesizing super heavy nuclei with hot fusion

2008 ◽  
Vol 57 (3) ◽  
pp. 1569
Author(s):  
Huang Ming-Hui ◽  
Gan Zai-Guo ◽  
Fan Hong-Mei ◽  
Su Peng-Yuan ◽  
Ma Long ◽  
...  
Keyword(s):  
Cross Sections ◽  
Heavy Nuclei ◽  
Super Heavy Nuclei ◽  
Driving Potential

ROLE OF MASS ASYMMETRY IN FUSION OF SUPER-HEAVY NUCLEI

2007 ◽  
Vol 16 (02) ◽  
pp. 483-490 ◽  
Author(s):  
K. SIWEK-WILCZYŃSKA ◽  
I. SKWIRA-CHALOT ◽  
J. WILCZYŃSKI
Keyword(s):  
Simple Model ◽  
Diffusion Equation ◽  
Cross Sections ◽  
Fusion Reaction ◽  
Capture Cross ◽  
Heavy Nuclei ◽  
Mass Asymmetry ◽  
Super Heavy Nuclei ◽  
Capture Cross Sections

By using well tested standard statistical model for calculating survival probabilities of super-heavy compound nuclei, Psurv, and reliably predicted capture cross sections σcap, "empirical" values of the fusion hindrance Pfus = σsyn/(σcap · Psurv) have been determined from the formation cross sections σsyn for production of super-heavy nuclei of 102 ≤ Z ≤ 113 measured at GSI Darmstadt and RIKEN. So determined fusion hindrance can be well reproduced with a simple model based on the Smoluchowski diffusion equation applied to describe thermal shape fluctuations of the fusing system. An applicability of this model for a wider class of fusing systems could be verified on data from an interesting experiment on the synthesis of isotopes of Hs (Z = 108) in the 136 Xe + 136 Xe reaction, scheduled to be carried out in Dubna this year. Synthesis cross sections for 269-271 Hs isotopes, strongly reduced by the fusion hindrance effect in this symmetric fusion reaction, are predicted.

scholarly journals Eighty years of research on super-heavy nuclei

2018 ◽  
Vol 182 ◽  
pp. 02054 ◽  
Author(s):  
Sigurd Hofmann
Keyword(s):  
Cross Sections ◽  
Production Cross ◽  
Heavy Ion ◽  
Experimental Investigations ◽  
Heavy Nuclei ◽  
Open Questions ◽  
Fission Barriers ◽  
Nuclear Shell ◽  
Closed Shells ◽  
Super Heavy Nuclei

Professor Walter Greiner, our mentor, colleague, and friend, passed away in the age of eighty. During his lifetime, the search for elements beyond uranium started and elements up to the so far heaviest one with atomic number 118 were discovered. In this talk I will present a short history from early searches for ‘trans-uraniums’ up to the production and safe identification of shell-stabilized ‘Super-Heavy Nuclei’ (SHN). The nuclear shell model reveals that these nuclei should be located in a region with closed shells for the protons at Z = 114, 120 or 126 and for the neutrons at N = 184. The outstanding aim of experimental investigations is the exploration of this region of spherical SHN. Systematic studies of heavy ion reactions for the synthesis of SHN revealed production cross-sections which reached values down to one picobarn and even below for the heaviest species. The systematics of measured cross-sections can be understood only on the basis of relatively high fission barriers as predicted for nuclei in and around the island of SHN. A key role in answering some of the open questions plays the synthesis of isotopes of element 120. Attempts aiming for synthesizing this element at the velocity filter SHIP will be reported.

Formation of α clusters in dilute neutron-rich matter

Science ◽  
2021 ◽  
Vol 371 (6526) ◽  
pp. 260-264 ◽  
Author(s):  
Junki Tanaka ◽  
Zaihong Yang ◽  
Stefan Typel ◽  
Satoshi Adachi ◽  
Shiwei Bai ◽  
...  
Keyword(s):  
Cross Sections ◽  
Cluster Formation ◽  
Reaction Cross ◽  
Skin Thickness ◽  
Neutron Skin ◽  
Heavy Nuclei ◽  
Α Decay ◽  
Neutron Skin Thickness ◽  
Reaction Cross Sections ◽  
Α Particles

The surface of neutron-rich heavy nuclei, with a neutron skin created by excess neutrons, provides an important terrestrial model system to study dilute neutron-rich matter. By using quasi-free α cluster–knockout reactions, we obtained direct experimental evidence for the formation of α clusters at the surface of neutron-rich tin isotopes. The observed monotonous decrease of the reaction cross sections with increasing mass number, in excellent agreement with the theoretical prediction, implies a tight interplay between α-cluster formation and the neutron skin. This result, in turn, calls for a revision of the correlation between the neutron-skin thickness and the density dependence of the symmetry energy, which is essential for understanding neutron stars. Our result also provides a natural explanation for the origin of α particles in α decay.

Fission of medium and heavy nuclei induced by 40Ar from 160 to 300 MeV: Cross sections

1975 ◽  
Vol 252 (1) ◽  
pp. 187-207 ◽  
Author(s):  
B. Tamain ◽  
C. Ngô ◽  
J. Péter ◽  
F. Hanappe
Keyword(s):  
Cross Sections ◽  
Heavy Nuclei

Radiative capture cross sections in medium-weight and heavy nuclei

1968 ◽  
Vol 119 (3) ◽  
pp. 673-690 ◽  
Author(s):  
P.J. Daly ◽  
B.M. Seppelt ◽  
P.F.D. Shaw
Keyword(s):  
Cross Sections ◽  
Radiative Capture ◽  
Capture Cross ◽  
Heavy Nuclei ◽  
Medium Weight ◽  
Capture Cross Sections
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