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.

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

MEASURING CAPTURE CROSS SECTIONS FOR HEAVY-ELEMENT PRODUCTION

2004 ◽  
Vol 13 (01) ◽  
pp. 293-300
Author(s):  
NEIL ROWLEY ◽  
NABILA GRAR
Keyword(s):  
Cross Section ◽  
Compound Nucleus ◽  
Cross Sections ◽  
Reaction Path ◽  
Superheavy Element ◽  
Evaporation Residue ◽  
Capture Cross ◽  
Total Capture ◽  
Capture Cross Sections

The creation of the nucleus of a superheavy element follows an extremely complex reaction path starting with the crossing of an external potential barrier (or distribution of barriers). This is followed by the evolution towards an equilibrated compound nucleus, which takes place in competition with pre-compound-nucleus fission (quasi-fission). Once formed the equilibrated compound nucleus must still survive against true fusion to yield a relatively long-lived evaporation residue. Much of this path is poorly understood, though recently, progress has been made on the role of the entrance-channel in quasi-fission. This will be briefly reported and a method proposed to measure the total capture cross section for such systems directly.

scholarly journals The role of e- capture in neutrino-nucleosynthesis

2019 ◽  
Vol 22 ◽  
pp. 84
Author(s):  
P. G. Giannaka ◽  
T. S. Kosmas
Keyword(s):  
Cross Sections ◽  
Random Phase Approximation ◽  
Random Phase ◽  
Capture Cross ◽  
Quasi Particle ◽  
Second Stage ◽  
Stellar Nucleosynthesis ◽  
Nuclear Method ◽  
Capture Cross Sections

In the first stage of this paper, we perform detailed calculations of the electron capture cross sections on nuclei under laboratory conditions. We use the nuclear method known as proton-neutron quasi-particle random phase approximation (pn-QRPA). In the second stage, we translate the above mentioned e--capture cross sections to the stellar environment. As a concrete nuclear target we use the 56Fe and the 66Zn isotopes, which belong to the iron group nuclei and play prominent role in stellar nucleosynthesis: i) in pre-supernova phase and ii) in supernova phase.

Simultaneous evaluation of fission and capture cross sections and their covariances for heavy nuclei

1986 ◽  
Vol 96 (1-4) ◽  
pp. 225-229 ◽  
Author(s):  
Yukinori Kanda ◽  
Yuji Uenohara ◽  
Toru Murata ◽  
Masayoshi Kawai ◽  
Hiroyuki Matsunobu ◽  
...  
Keyword(s):  
Cross Sections ◽  
Capture Cross ◽  
Heavy Nuclei ◽  
Simultaneous Evaluation ◽  
Capture Cross Sections

scholarly journals Capture cross sections for the synthesis of new heavy nuclei using radioactive beams

2018 ◽  
Vol 97 (2) ◽  
Author(s):  
A. Wakhle ◽  
K. Hammerton ◽  
Z. Kohley ◽  
D. J. Morrissey ◽  
K. Stiefel ◽  
...  
Keyword(s):  
Cross Sections ◽  
Capture Cross ◽  
Heavy Nuclei ◽  
Radioactive Beams ◽  
Capture Cross Sections

scholarly journals Phenomenological Description of Neutron Capture Cross Sections at 30 keV

2013 ◽  
Vol 2013 ◽  
pp. 1-8
Author(s):  
M. Kiss ◽  
Z. Trócsányi
Keyword(s):  
Cross Sections ◽  
Neutron Capture ◽  
Phenomenological Description ◽  
Capture Cross ◽  
Heavy Nuclei ◽  
Proton Number ◽  
The Cross ◽  
Capture Cross Sections

Studying the published values of Maxwellian-averaged neutron capture cross sections, we found simple phenomenological rules obeyed by the cross sections as a function of proton and neutron numbers. We use these rules to make predictions for cross sections of neutron capture on nuclei with proton number above 83, where very few MACS data are available. These predictions may be useful in certain models of nucleosynthesis of heavy nuclei in stars.

Thermal Quenching and Photo-Enhancement of μτ Products in a-Si:H - The Role of Dangling Bonds and Band Tails

1994 ◽  
Vol 336 ◽  
Author(s):  
E. Morgado
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Capture Cross Section ◽  
Thermal Quenching ◽  
Capture Cross ◽  
Dangling Bond ◽  
Temperature Dependences ◽  
Capture Cross Sections ◽  
Band Tails

ABSTRACTResults from numerical calculations with a recombination model involving one class of correlated dangling-bond states and exponential band tails, in a-Si:H, are reported. Fermi level, light intensity and temperature dependences of the μτ products are studied. The results are consistent with experimental data. It is found that photo-enhancement of (μτ)e, or superlinear photoconductivity, as well as thermal quenching, are associated with a capture cross section of the band tails smaller than the capture cross sections of the dangling-bond states.

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