Evaporation residue cross sections and average neutron multiplicities in the 64Ni+92Zr and 12C+144Sm reactions leading to 156Er

A schematic model for the description of (p, xn) reactions in heavy elements is presented. Reactions are divided into two steps, a prompt multiple collision process, followed by an evaporation stage. The various prompt processes are given by the results of Monte Carlo calculations, while the evaporation processes are described by a simplified model assuming constant nuclear temperatures and only neutron evaporation. The resulting (p, xn), and to a minor degree (p, pxn), cross sections are compared with the experimental data of Bell and Skarsgard (1956) in the energy range up to 100 Mev. With an average neutron binding energy of around 7.3 Mev., a nuclear temperature of about 1.8 Mev., and a nuclear radius of 8.0 × 10−13 cm., a reasonable over-all fit can be made to the data for Pb206, Pb207, Pb208, and Bi209. Characteristic fluctuations in the experimental results for the (p, 2n), (p, 3n), and (p, 4n) reactions for all targets seem to be attributable to variations in the total reaction cross section, and are not reproduced by the present model.

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Investigation of the synthesis of the unknown superheavy nuclei 309,312126

International Journal of Modern Physics E ◽

10.1142/s0218301319500563 ◽

2019 ◽

Vol 28 (07) ◽

pp. 1950056 ◽

Cited By ~ 3

Author(s):

T. V. Nhan Hao ◽

N. N. Duy ◽

K. Y. Chae ◽

N. Quang Hung ◽

N. Nhu Le

Keyword(s):

Cross Section ◽

Cross Sections ◽

Charge Asymmetry ◽

Evaporation Residue ◽

Fission Process ◽

Dinuclear System ◽

Mass Asymmetry ◽

Interacting Systems ◽

First Time ◽

Text Element

In this paper, we applied the method developed by Santhosh and Safoora in [Phys. Rev. C 94 (2016) 024623; 95 (2017) 064611] to theoretically investigate the fusion, evaporation-residue (ER) and fission cross-sections of the synthesis of the unknown superheavy [Formula: see text]126 nuclei produced by using the [Formula: see text]Ni + [Formula: see text]Cf and [Formula: see text]Zn + [Formula: see text]Cm combinations. The charge asymmetry, mass asymmetry and fissility of the DiNuclear System (DNS) in the synthesis of the mentioned combinations are also estimated. The calculated results show that the ER cross-sections for the synthesis of the [Formula: see text]126 nuclei are predicted to be much less than 1.0[Formula: see text]fb. In particular, it has been found that there may exist a valley of the ER cross-sections in the synthesis of a superheavy [Formula: see text] element, which produces the [Formula: see text]126 isotope. Subsequently, a model for the mass dependence of the ER cross-section in the synthesis of the [Formula: see text]126 isotopes has been proposed for the first time. On the other hand, the quasi-fission process strongly dominates over the fusion in the two concerned interacting systems. The present results, together with those reported in the previous studies, indicate that the investigated projectile–target combinations are not capable for the synthesis of the [Formula: see text]126 isotopes due to tiny fusion cross-sections (about 2–3[Formula: see text]zb), which go beyond the limitations of available facilities. Further studies are thus recommended to search for alternative interacting systems. In conclusion, this work provides useful information for the synthesis of the gap isotopes [Formula: see text]126, which have not been well studied up to date.

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Evaporation residue cross-sections as a probe for nuclear dissipation in the fission channel of a hot rotating nucleus

The European Physical Journal A ◽

10.1140/epja/i2003-10038-x ◽

2003 ◽

Vol 18 (1) ◽

pp. 9-15 ◽

Cited By ~ 22

Author(s):

Gargi Chaudhuri ◽

Santanu Pal

Keyword(s):

Cross Sections ◽

Evaporation Residue ◽

Nuclear Dissipation

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MEASURING CAPTURE CROSS SECTIONS FOR HEAVY-ELEMENT PRODUCTION

International Journal of Modern Physics E ◽

10.1142/s0218301304002077 ◽

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.

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COMPARISON OF THE FUSION-FISSION AND QUASIFISSION MECHANISMS IN HEAVY-ION COLLISIONS

International Journal of Modern Physics E ◽

10.1142/s021830130901294x ◽

2009 ◽

Vol 18 (04) ◽

pp. 841-849 ◽

Cited By ~ 5

Author(s):

AVAZBEK NASIROV ◽

GIOVANNI FAZIO ◽

GIORGIO GIARDINA ◽

GIUSEPPE MANDAGLIO ◽

MARINA MANGANARO ◽

...

Keyword(s):

Cross Sections ◽

Theoretical Method ◽

Heavy Ion ◽

Evaporation Residue ◽

System Model ◽

Complete Fusion ◽

Dinuclear System ◽

Ion Collisions ◽

Partial Fusion ◽

Evaporation Residues

The decrease of the evaporation residue yields in reactions with massive nuclei is explained by an increase of the competition between quasifission and complete fusion processes and by the decrease of the survival probability of the heated and rotating nuclei against fission along the de-excitation cascade of the compound nucleus. The experimental data on the yields of evaporation residue, fusion-fission and quasifission fragments in the 48 Ca + 154 Sm reaction are analyzed in the framework of the combined theoretical method based on the dinuclear system concept and advanced statistical model. The measured yields of evaporation residues of the 48 Ca + 154 Sm reaction have been well reproduced and yields of fission fragments were analyzed using the partial fusion and quasifission cross sections calculated in the dinuclear system model. Such a way of calculation is used to find optimal conditions for the synthesis of the new element Z = 120 (A = 302) by studying the excitation functions of evaporation residues of the 54 Cr + 248 Cm , 58 Fe + 244 Pu , and 64 Ni + 238 U reactions. Our estimations show that the 54 Cr + 248 Cm reaction is preferable in comparison with the two others.

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