Evaporation-residue cross sections: role of the entrance channel

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.

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Significant role of fissility in evaporation residue cross sections as a probe of presaddle nuclear dissipation

Physical Review C ◽

10.1103/physrevc.81.011603 ◽

2010 ◽

Vol 81 (1) ◽

Cited By ~ 20

Author(s):

W. Ye

Keyword(s):

Significant Role ◽

Cross Sections ◽

Evaporation Residue ◽

Nuclear Dissipation

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Fragment mass identification and related aspects in the decay of 40Ca* and 39K* nuclei

International Journal of Modern Physics E ◽

10.1142/s0218301314500633 ◽

2014 ◽

Vol 23 (10) ◽

pp. 1450063 ◽

Cited By ~ 4

Author(s):

Gurvinder Kaur ◽

Manoj K. Sharma

Keyword(s):

Cross Sections ◽

Entrance Channel ◽

Cluster Decay ◽

Channel Effects ◽

Nice Agreement ◽

The Cross ◽

Fragmentation Potential ◽

First Time ◽

Mass Identification

The dynamics involved in the decay of light mass nuclei formed in asymmetric channels 12 C + 28 Si , 11 B + 28 Si and 12 C + 27 Al have been investigated using the dynamical cluster-decay model (DCM). In reference to the experimentally measured charge particle cross-sections, the fragment masses contributing towards the decay of 40 Ca * and 39 K * nuclei have been identified using spherical choice of fragmentation. Also, the role of entrance channel has been investigated by studying the decay of 39 K * nuclear system formed in two different reactions at same excitation energy. The behavior of fragmentation potential, preformation probability, penetrability and emission time, is analyzed to figure out the favorable mass fragments, their relative emergence and the entrance channel effects observed in the decay of light mass nuclei. In addition to this, the cross-sections for the light particles (LPs) and heavier charge fragments have been estimated for the compound nucleus (CN) decay. Besides this, one of the noncompound nucleus (nCN) process, deep inelastic collision (DIC) has been addressed in context of DCM approach for the first time. The cross-sections obtained in framework of DCM for both CN and nCN processes are found to have nice agreement with the available experimental data.

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INFLUENCE OF ENTRANCE-CHANNEL SHELL EFFECTS ON FUSION HINDRANCE

International Journal of Modern Physics E ◽

10.1142/s0218301308009513 ◽

2008 ◽

Vol 17 (01) ◽

pp. 23-30

Author(s):

J. BŁOCKI ◽

J. WILCZYŃSKI

Keyword(s):

Diffusion Model ◽

Cross Sections ◽

Evaporation Residue ◽

Entrance Channel ◽

Dynamical Model ◽

Striking Difference ◽

Injection Point ◽

Shell Effects ◽

Diffusion Stage

A study is presented to what extent a striking difference in the evaporation-residue cross sections for two reactions, 86 Kr + 130 Xe and 86 Kr + 136 Xe , originates from different shell effects in 130 Xe and 136 Xe nuclei. A classical dynamical model with one-body dissipation was used to calculate the injection point to the "diffusion" stage of the Fusion-by-Diffusion model of Światecki, Siwek-Wilczyńska and Wilczyński. Only a factor of 6 in the ratio of the fusion hindrance factors in these two reactions can be associated with the entrance-channel shell effects.

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Oxygen K near edge structures studied with multiple scattering calculations

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100104583 ◽

1988 ◽

Vol 46 ◽

pp. 504-505

Author(s):

Xudong Weng ◽

Peter Rez

Keyword(s):

Cross Section ◽

Cross Sections ◽

Partial Cross Section ◽

Energy Window ◽

Edge Structure ◽

Fine Structures ◽

Hydrogenic Model ◽

Electron Energy Loss ◽

Quantitative Chemical

In electron energy loss spectroscopy, quantitative chemical microanalysis is performed by comparison of the intensity under a specific inner shell edge with the corresponding partial cross section. There are two commonly used models for calculations of atomic partial cross sections, the hydrogenic model and the Hartree-Slater model. Partial cross sections could also be measured from standards of known compositions. These partial cross sections are complicated by variations in the edge shapes, such as the near edge structure (ELNES) and extended fine structures (ELEXFS). The role of these solid state effects in the partial cross sections, and the transferability of the partial cross sections from material to material, has yet to be fully explored. In this work, we consider the oxygen K edge in several oxides as oxygen is present in many materials. Since the energy window of interest is in the range of 20-100 eV, we limit ourselves to the near edge structures.

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An Study of Influence of Imperfections on the Delamination of Diamond-Like Carbon Films

MRS Proceedings ◽

10.1557/proc-719-f8.36 ◽

2002 ◽

Vol 719 ◽

Author(s):

Myoung-Woon Moon ◽

Kyang-Ryel Lee ◽

Jin-Won Chung ◽

Kyu Hwan Oh

Keyword(s):

Cross Sections ◽

Focused Ion Beam ◽

Imaging System ◽

Ion Beam ◽

Carbon Films ◽

Diamond Like Carbon ◽

Glass Substrates ◽

Atomic Force ◽

Initiation And Propagation

AbstractThe role of imperfections on the initiation and propagation of interface delaminations in compressed thin films has been analyzed using experiments with diamond-like carbon (DLC) films deposited onto glass substrates. The surface topologies and interface separations have been characterized by using the Atomic Force Microscope (AFM) and the Focused Ion Beam (FIB) imaging system. The lengths and amplitudes of numerous imperfections have been measured by AFM and the interface separations characterized on cross sections made with the FIB. Chemical analysis of several sites, performed using Auger Electron Spectroscopy (AES), has revealed the origin of the imperfections. The incidence of buckles has been correlated with the imperfection length.

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CONVEX VALLEY CROSS-SECTIONS OF MOUNT RAINER RIVERS AND THE ROLE OF FORESTS AND LOGJAMS AS LIMITATIONS TO CHANNEL MIGRATION

10.1130/abs/2017am-307970 ◽

2017 ◽

Author(s):

Tim Abbe ◽

Keyword(s):

Cross Sections ◽

Channel Migration

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Role of α-Cluster Transfer in the Formation of 20Ne + 16O Cross-Sections at Backward Angles

Brazilian Journal of Physics ◽

10.1007/s13538-021-00900-z ◽

2021 ◽

Vol 51 (3) ◽

pp. 780-787

Author(s):

Sh. Hamada ◽

Nourhan M. Elmedalaa ◽

I. Bondouk ◽

N. Darwish ◽

Awad A. Ibraheem

Keyword(s):

Cross Sections ◽

Cluster Transfer

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Few Body Effects in the Electron and Positron Impact Ionization of Atoms

Atoms ◽

10.3390/atoms9020033 ◽

2021 ◽

Vol 9 (2) ◽

pp. 33

Author(s):

R.I. Campeanu ◽

Colm T. Whelan

Keyword(s):

Electron Impact ◽

Cross Sections ◽

Differential Cross ◽

Impact Ionization ◽

Inert Gas ◽

Interference Effects ◽

Positron Impact ◽

Competing Interactions ◽

Energy Sharing

Triple differential cross sections (TDCS) are presented for the electron and positron impact ionization of inert gas atoms in a range of energy sharing geometries where a number of significant few body effects compete to define the shape of the TDCS. Using both positrons and electrons as projectiles has opened up the possibility of performing complementary studies which could effectively isolate competing interactions that cannot be separately detected in an experiment with a single projectile. Results will be presented in kinematics where the electron impact ionization appears to be well understood and using the same kinematics positron cross sections will be presented. The kinematics are then varied in order to focus on the role of distortion, post collision interaction (pci), and interference effects.

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