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.

MEASUREMENT AND ANALYSIS OF EXCITATION FUNCTIONS FOR ALPHA-INDUCED REACTIONS IN BISMUTH

1992 ◽  
Vol 01 (04) ◽  
pp. 823-831 ◽  
Author(s):  
B. P. SINGH ◽  
M. G. V. SANKARACHARYULU ◽  
M. A. ANSARI ◽  
R. PRASAD ◽  
H. D. BHARDWAJ
Keyword(s):  
Energy Range ◽  
Compound Nucleus ◽  
Projectile Energy ◽  
Exciton Model ◽  
Excitation Functions ◽  
Model Calculations ◽  
Stacked Foil Technique ◽  
Measurement And Analysis ◽  
Foil Technique

Excitation functions for 209 Bi (α, 3n), 209 Bi (α, 4n) and 209 Bi (α, 5n) reactions have been measured in the energy range threshold to ≈50 MeV using stacked foil technique. Excitation functions have also been theoretically calculated and as expected, inclusion of pre-equilibrium contribution based on exciton model calculations along with compound nucleus calculations using Hauser–Feshbach formalism reproduces well the measured excitation functions. Interesting trend in the ratio of pre-equilibrium to equilibrium component with projectile energy has been observed.

Study of proton induced nuclear reactions on molybdenum: cross section measurements and theoretical calculations

2019 ◽  
Vol 108 (1) ◽  
pp. 1-9
Author(s):  
Alaa Elbinawi ◽  
Mogahed Al-abyad ◽  
Ibrahim Bashter ◽  
Usama Seddik ◽  
Ferenc Ditrói
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Nuclear Reactions ◽  
Theoretical Calculations ◽  
Experimental Results ◽  
Excitation Functions ◽  
Stacked Foil Technique ◽  
Theoretical Results ◽  
Production Conditions ◽  
Foil Technique

Abstract Excitation functions were measured by the activation method using the stacked-foil technique for the natMo(p,x)93(m+g),94m,g,95m,g,96(m+g),99mTc, 92m,95Nb reactions up to 18 MeV. The experimental results were compared with literature data and theoretical results from EMPIRE-3.2.2 code and TENDL. Special attention was paid to the 100Mo(p,2n)99mTc reaction which is very promising for the production of 99mTc at a cyclotron. In order to optimize the production conditions of some medically important Tc isotopes, the integral yields were estimated based on the measured cross sections.

Non-equilibrium emission of neutrons in α-particle induced reactions with holmium

2008 ◽  
Vol 86 (3) ◽  
pp. 495-500 ◽  
Author(s):  
Avinash Agarwal ◽  
I A Rizvi ◽  
A K Chaubey
Keyword(s):  
Compound Nucleus ◽  
Computer Code ◽  
High Energy ◽  
Activation Technique ◽  
Excitation Functions ◽  
Equilibrium Reaction ◽  
Experimental Trend ◽  
Γ Ray ◽  
Stacked Foil Activation Technique ◽  
Equilibrium Emission

The stacked-foil activation technique followed by off line high-purity Ge γ-ray spectroscopy was used for the measurement of the excitation functions for energies up to 50 MeV for the 165Ho(α, 2n) 167Tm, 165Ho(α, 3n) 166Tm, and 165Ho(α, 4n) 165Tm reactions. The measured excitation functions were compared with theoretical predications considering equilibrium as well as pre-equilibrium reaction mechanisms according to the geometry-dependent hybrid (GDH) model of Blann using computer code ALICE-91. The high-energy parts of the excitation functions are due to the pre-equilibrium reaction mechanism, while the low-energy parts are mediated by compound-nucleus decay. It was found that the compound-nucleus-decay mechanism alone is unable to explain the experimental trend of our data. The pre-equilibrium fraction was also calculated. PACS Nos.: 22.55.–e, 27.60.+j

PRE-EQUILIBRIUM EMISSION IN DIFFERENTIAL CROSS-SECTION CALCULATIONS AND ANALYSIS OF EXPERIMENTAL DATA FOR 232Th

2004 ◽  
Vol 19 (21) ◽  
pp. 1597-1614 ◽  
Author(s):  
E. TEL ◽  
İ DEMİRKOL ◽  
A. ARASOĞLU ◽  
B. ŞARER
Keyword(s):  
Experimental Data ◽  
Cross Sections ◽  
Neutron Emission ◽  
Emission Spectra ◽  
Exciton Model ◽  
Quantum Mechanical Theory ◽  
Geometry Dependent Hybrid Model ◽  
Neutron Emission Spectra ◽  
Equilibrium Matrix ◽  
Equilibrium Emission

In this study, neutron-emission spectra produced by (n,xn) reactions on nuclei 232 Th have been calculated. Angle-integrated cross-sections in neutron induced reactions on targets 232 Th have been calculated at the bombarding energies from 2 MeV to 18 MeV. We have investigated multiple pre-equilibrium matrix element constant from internal transition for 232 Th (n,xn) neutron emission spectra. In the calculations, the geometry dependent hybrid model and the cascade exciton model including the effects of pre-equilibrium have been used. Pre-equilibrium direct effects have been examined by using full exciton model. In addition, we have described how multiple pre-equilibrium emissions can be included in the Feshbach–Kerman–Koonin (FKK) fully quantum-mechanical theory. By analyzing (n,xn) reaction on 232 Th , with the incident energy from 2 MeV to 18 MeV, the importance of multiple pre-equilibrium emission can be seen clearly. All calculated results have been compared with experimental data. The obtained results have been discussed and compared with the available experimental data and found agreement with each other.

scholarly journals Validation of nuclear reaction models for incident α-particles

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Hartmut Machner
Keyword(s):  
Nuclear Reaction ◽  
Compound Nucleus ◽  
Neutron Emission ◽  
Cascade Model ◽  
The Other ◽  
Reaction Products ◽  
Exciton Model ◽  
Intranuclear Cascade ◽  
Reaction Models ◽  
Α Particles

AbstractTwo different models allowing the calculation of reaction products are confronted with data from α-particle induced reactions. Both models contain a pre-equilibrium part and an equilibrium or compound nucleus part. The models are the exciton model in form of a code written by the author and TALYS. The other model is the intranuclear cascade model in form of the Liege-Saclay formulation incorporated in the PHITS code. The data are angle-integrated proton spectra from reactions with α-particle energies below 720 MeV and excitation functions from multi neutron emission with α-particle energies below 200 MeV.

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).

Experimental studies and nuclear model calculations on (p, xn) and (p, pxn) reactions on 85Rb from their thresholds up to 100 MeV

2004 ◽  
Vol 92 (8) ◽  
Author(s):  
S. Kastleiner ◽  
Yu. N. Shubin ◽  
F. M. Nortier ◽  
T.N. van der Walt ◽  
Syed M. Qaim
Keyword(s):  
Experimental Studies ◽  
Nuclear Model ◽  
Excitation Functions ◽  
Model Calculations ◽  
Stacked Foil Technique ◽  
Foil Technique

SummaryExcitation functions were measured by the stacked-foil technique for the reactions

scholarly journals Radiochemical studies relevant to the production of 86Y and 88Y at a small-sized cyclotron

2002 ◽  
Vol 90 (12) ◽  
Author(s):  
K. Kettern ◽  
K.-H. Linse ◽  
S. Spellerberg ◽  
Heinz H. Coenen ◽  
Syed M. Qaim
Keyword(s):  
Excitation Functions ◽  
Stacked Foil Technique ◽  
Foil Technique

SummaryExcitation functions were measured by the stacked–foil technique for

A STUDY OF EXCITATION FUNCTIONS FOR SOME RESIDUES PRODUCED IN THE SYSTEM 14N+128Te IN THE ENERGY RANGE ≈ 64–90 MeV

2005 ◽  
Vol 14 (05) ◽  
pp. 775-786 ◽  
Author(s):  
UNNATI ◽  
MANOJ KUMAR SHARMA ◽  
B. P. SINGH ◽  
R. PRASAD ◽  
SUNITA GUPTA ◽  
...  
Keyword(s):  
Energy Range ◽  
Theoretical Calculations ◽  
Computer Programs ◽  
Incomplete Fusion ◽  
Complete Fusion ◽  
Activation Technique ◽  
Excitation Functions ◽  
First Time ◽  
Equilibrium Emission

The excitation functions for eight reactions produced in the interaction of 14 N +128 Te have been measured in the energy range ≈ 64–90 MeV using the activation technique. To the best of our knowledge these measurements have been performed for the first time. The measured excitation functions are compared with theoretical calculations done using the computer programs ALICE-91 and PACE. The effect of the variation of various program parameters on calculated excitation functions have been studied. The present analysis indicates that complete fusion, incomplete fusion and pre-equilibrium emission processes play important roles in these reactions.

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