PRE-EQUILIBRIUM FRACTION IN ALPHA INDUCED REACTIONS FROM THRESHOLD TO 40 MeV

1995 ◽  
Vol 04 (03) ◽  
pp. 539-546
Author(s):  
K.S. VARSHNEY ◽  
J.P. GUPTA
Keyword(s):  
Statistical Model ◽  
Excitation Energy ◽  
Atomic Number ◽  
Asymmetry Parameter ◽  
Mass Number ◽  
Neutron Number ◽  
Excitation Functions ◽  
Equilibrium Fraction ◽  
Target Mass ◽  
Equilibrium Emission

α-particle induced excitation functions for the reactions 55Mn (α, n), 63Cu (α, n), 65Cu (α, n), 107Ag (α, n), 121Sb (α, n), 123Sb (α, n), 165Ho (α, n), 197Au (α, n), in a number of target nuclei from A=55 to 197(Z=25 to 83) have been calculated using the Statistical Model with and without inclusion of pre-equilibrium particle emission in the energy from threshold to 40 MeV. It is found that without consideration of pre-equilibrium decay, the data are not reproducible. As expected, inclusion of pre-equilibrium emission in compound nucleus calculation agree well with the experimental excitation functions. The pre-equilibrium fraction (FR) is found to be dependent on excitation energy, target mass number, neutron number, atomic number and, asymmetry parameter (N−Z).

A study of pre-equilibrium emission in α-induced reactions on 121,123Sb

1991 ◽  
Vol 69 (11) ◽  
pp. 1376-1382 ◽  
Author(s):  
B. P. Singh ◽  
H. D. Bhardwaj ◽  
R. Prasad
Keyword(s):  
Compound Nucleus ◽  
Mass Number ◽  
Neutron Emission ◽  
Theoretical Calculations ◽  
Exciton Model ◽  
Excitation Functions ◽  
Stacked Foil Technique ◽  
Equilibrium Emission ◽  
Charged Particle Emission ◽  
Foil Technique

Excitation functions for the 121Sb (α, n)+ 123Sb(α, 3n),,21Sb(α, 2n)+ 123Sb(α, 4n), 121Sb(α, 4n), 121Sb(α, 3np), and 123Sb(α, n) reactions are measured in the energy range 30–60 MeV using the stacked foil technique. In the cases of the 121Sb(α, n)+ 123Sb(α, 3n) and 121Sb(α, 2n)+ 123Sb(α, 4n) reaction pairs, the excitation functions for individual reactions were deduced using theoretical calculations. Excitation functions are also calculated theoretically using the compound-nucleus model with and without the inclusion of a pre-equilibrium emission. As expected, inclusion of a pre-equilibrium contribution based on the exciton model along with compound-nucleus calculations using the Hauser–Feshbach formalism reproduces well the measured excitation functions. Analysis of the data indicates a preference for a first chance neutron emission over charged-particle emission, and interesting trends in the energy and mass-number dependence of the pre-equilibrium fraction are observed.

SOME CHARACTERISTICS OF THE COMPOUND MULTIPLICITY IN HIGH-ENERGY NUCLEUS–NUCLEUS INTERACTIONS

2011 ◽  
Vol 20 (08) ◽  
pp. 1735-1754 ◽  
Author(s):  
M. MOHERY ◽  
M. ARAFA
Keyword(s):  
Experimental Data ◽  
Impact Parameter ◽  
Mass Number ◽  
Multiplicity Distribution ◽  
High Energy ◽  
Projectile Nucleus ◽  
Target Mass ◽  
Compound Multiplicity ◽  
Multiplicity Distributions ◽  
The Impact

The present paper deals with the interactions of 22 Ne and 28 Si nuclei at (4.1–4.5)A GeV /c with emulsion. Some characteristics of the compound multiplicity nc given by the sum of the number of shower particles ns and grey particles ng have been investigated. The present experimental data are compared with the corresponding ones calculated according to modified cascade evaporation model (MCEM). The results reveal that the compound multiplicity distributions for these two reactions are consistent with the corresponding ones of MCEM data. It can also be seen that the peak of these distributions shifts towards a higher value of nc with increasing projectile mass. It may further be seen that the compound multiplicity distributions becomes broader with increasing target size and its width increases with the size of the projectile nucleus. In addition, it has been found that the MCEM can describe the compound multiplicity characteristics of the different projectile, target and the correlation between different emitted particles. The values of average compound multiplicity increase with increasing mass of the projectile. Furthermore, it is observed that while the value of 〈nc〉 depends on the mass number of the projectile Ap and the target mass number At, the value of the ratio 〈nc〉/D(nc) seems to be independent of Ap and At. The impact parameter is found to affect the shape of the compound multiplicity distribution. Finally, the dependence of the average compound multiplicity on the numbers of grey and black particles, and the sum of them, is obvious. The values of the slope have been found to be independent of the projectile nucleus.

scholarly journals Statistical model calculations of 72,73Ge(n,p) and 72,74Ge(n,α) reactions on natural Ge

2020 ◽  
Vol 15 ◽  
pp. 104
Author(s):  
S. Galanopoulos ◽  
R. Vlastou ◽  
P. Demetriou ◽  
M. Kokkoris ◽  
C. T. Papadopoulos ◽  
...  
Keyword(s):  
Statistical Model ◽  
Energy Range ◽  
Neutron Energy ◽  
Cross Sections ◽  
Reaction Cross ◽  
Model Calculations ◽  
Monoenergetic Neutron ◽  
Theoretical Investigations ◽  
Equilibrium Emission ◽  
Reaction Cross Sections

Systematic experimental and theoretical investigations of the 72,73Ge(n,p)72,73 Ga and 72,74Ge(n,α)69,71Znm reaction cross sections are presented in the energy range from thresh- old to about 17 MeV neutron energy. The above reaction cross sections were measured from 8.8 to 11.4 MeV by using the activation method, relative to the 27Al(n,α)24Na refer- ence reaction. The quasi-monoenergetic neutron beams were produced via the 2H(d,n)3He reaction at the 5 MV VdG Tandem T11/25 accelerator of NCSR “Demokritos”. Statisti- cal model calculations using the code EMPIRE-II (version 2.19) taking into consideration pre-equilibrium emission were performed on the data measured in this work as well as on data reported in literature.

On Z=2 Projectile Fragments Emitted in the Interactions of 3.7A GeV 28Si in Nuclear Emulsions

1998 ◽  
Vol 07 (03) ◽  
pp. 341-355 ◽  
Author(s):  
B. K. Singh ◽  
S. K. Tuli
Keyword(s):  
Excitation Energy ◽  
Cross Sections ◽  
Mass Number ◽  
Multiplicity Distribution ◽  
Production Cross ◽  
Emission Angle ◽  
Single Source ◽  
Momentum Spread ◽  
Nuclear Emulsions ◽  
Scaling Behaviour

We report the results on partial production cross sections for Z=2 projectile fragments emitted in 28Si-emulsion interactions at 3.7 A GeV. Scaling behaviour of the multiplicity distribution of Z=2 PFs has been checked. The emission angle of Z=2 PFs has been measured and pseudorapidity distributions for these PFs have been obtained. We observe that the value of momentum spread σ(p) for Z=2 PFs grows with increasing mass number of the projectile. The emission of Z=2 PFs is consistent with a single source with an excitation energy of about 8.9 MeV. The data has been compared with available data reported for lighter as well as heavier projectiles at the same and/or different energies.

Investigations on the study of entrance channel effects in synthesis of superheavy elements using Cr-induced fusion reactions

2020 ◽  
Vol 29 (08) ◽  
pp. 2050061
Author(s):  
H. C. Manjunatha ◽  
N. Manjunatha ◽  
L. Seenappa
Keyword(s):  
Atomic Number ◽  
Asymmetry Parameter ◽  
Superheavy Elements ◽  
Entrance Channel ◽  
Heavy Nuclei ◽  
Fusion Reactions ◽  
Number Range ◽  
Mass Asymmetry ◽  
Number Formula ◽  
Super Heavy Nuclei

We have investigated the synthesis of superheavy elements using Cr-induced fusion reactions. We have studied all possible Cr-induced fusion reactions for the synthesis of super heavy nuclei [Formula: see text]. We have achieved the semi-empirical formula for fusion barrier heights ([Formula: see text]), positions ([Formula: see text]), curvature of the inverted parabola ([Formula: see text]) of Cr-induced fusion reactions for the synthesis of superheavy nuclei with atomic number range [Formula: see text]. The proposed formula produces fusion barriers of Cr-induced fusion reactions for the synthesis of super heavy nuclei with the simple inputs of mass number ([Formula: see text]) and atomic number ([Formula: see text]) of projectile-targets. We have also identified the targets for Cr-induced fusion reactions to synthesis superheavy elements of [Formula: see text]. We have also studied the entrance channel parameters such as mass asymmetry ([Formula: see text]), charge asymmetry ([Formula: see text]), coulomb interaction parameter ([Formula: see text]’), Businaro–Gallone mass asymmetry parameter ([Formula: see text]) and Isospin asymmetry parameter [[Formula: see text]]. We hope that our predictions may be the guide for the future experiments in the synthesis of more superheavy elements using [Formula: see text]Cr-induced fusion reactions.

Analysis of excitation functions via the compound statistical model

1965 ◽  
Vol 69 (2) ◽  
pp. 401-422 ◽  
Author(s):  
R.A. Esterlund ◽  
B.D. Pate
Keyword(s):  
Statistical Model ◽  
Excitation Functions
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