NEUTRON EVAPORATION IN THE 14-MEV NEUTRON FISSION OF URANIUM

1961 ◽  
Vol 39 (7) ◽  
pp. 967-975 ◽  
Author(s):  
G. C. Hanna ◽  
R. L. Clarke
Keyword(s):  
Experimental Data ◽  
Cross Sections ◽  
Neutron Emission ◽  
Neutron Energy Spectrum ◽  
Measured Intensity ◽  
Neutron Fission ◽  
Fission Fragments ◽  
Neutron Evaporation ◽  
Neutron Multiplicities ◽  
Calculated Number

The numbers of prefission and postfission neutrons expected from the 14-Mev neutron fission of uranium have been calculated from the experimental data on partial cross sections and neutron multiplicities. It has been assumed that the competition between neutron emission and fission does not change with increasing energy beyond threshold. The neutron energy spectrum measured recently by Clarke gives a smaller intensity in the energy range 4–6 Mev than is expected from the calculated number of postfission neutrons. The measured intensity suggests that only 2.1 ± 0.5 neutrons are evaporated from the moving fission fragments.

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.

FUSION-FISSION AND QUASI-FISSION PROCESSES IN REACTIONS USING ACTINIDE TARGET NUCLEI

2010 ◽  
Vol 19 (05n06) ◽  
pp. 813-824
Author(s):  
YOSHIHIRO ARITOMO
Keyword(s):  
Experimental Data ◽  
Nuclear Structure ◽  
Energy Dependence ◽  
Mass Distribution ◽  
Cross Sections ◽  
Langevin Equation ◽  
Incident Energy ◽  
Dynamical Model ◽  
Fission Fragments ◽  
Fine Structures

We analyzed experimental data obtained for the mass distribution of fission fragments in the reactions 36 S +238 U and 30 Si +238 U at several incident energies, which were performed by the JAEA group. Using the dynamical model with the Langevin equation, we precisely investigate the incident energy dependence of the mass distribution of fission fragments. We also consider the fine structures in the mass distribution of fission fragments caused by the nuclear structure at a low incident energy. It is explained why the mass distribution of fission fragments has different features in the two reactions. The fusion cross sections are also estimated.

PRODUCTION OF HEAVY ELEMENTS BY TRANSFER OF MASSIVE CLUSTERS

1992 ◽  
Vol 01 (02) ◽  
pp. 221-247 ◽  
Author(s):  
M. T. MAGDA ◽  
J. D. LEYBA
Keyword(s):  
Experimental Data ◽  
Cross Sections ◽  
Target Nucleus ◽  
Heavy Elements ◽  
Transfer Reactions ◽  
Isotopic Distribution ◽  
Neutron Evaporation ◽  
Massive Clusters ◽  
Multinucleon Transfer Reactions ◽  
Good Agreement

A review of various models of multinucleon transfer reactions leading to heavy elements is given. A mechanism is proposed to describe these reactions based on the assumption that massive clusters are separated from the projectile and captured as a whole by the target nucleus. The modification of the primary isotopic distribution by fission and neutron evaporation is considered. Calculated isotopic distributions and cross sections are in good agreement with experimental data for the production of Z = 96–103 elements. Predictions of the model are used to explore the possibilities of producing transfermium elements by transfer reactions.

APPEARANCE OF FAST-FISSION AND QUASI-FISSION IN REACTIONS WITH MASSIVE NUCLEI

2005 ◽  
Vol 20 (06) ◽  
pp. 391-405 ◽  
Author(s):  
GIOVANNI FAZIO ◽  
GIORGIO GIARDINA ◽  
GIUSEPPE MANDAGLIO ◽  
FRANCIS HANAPPE ◽  
AKHTAM I. MUMINOV ◽  
...  
Keyword(s):  
Experimental Data ◽  
Reaction Mechanism ◽  
Excitation Function ◽  
Cross Sections ◽  
Neutron Emission ◽  
Evaporation Residue ◽  
Dinuclear System ◽  
Total Evaporation ◽  
Fast Fission ◽  
Evaporation Residues

The experimental data on the capture and evaporation residue cross-sections obtained in the 48 Ca +208 Pb reaction were analyzed in the framework of the dynamical model based on the dinuclear system concept and advanced statistical method to clarify the reaction mechanism. The experimental excitation function of the capture reactions was decomposed into contributions of the fusion–fission, quasifission and fast-fission processes. Total evaporation residues and ones after neutron emission were only calculated and compared with the available experimental data.

scholarly journals Prompt Neutrons From 236U Fission Fragments

1971 ◽  
Vol 24 (4) ◽  
pp. 821 ◽  
Author(s):  
JW Boldeman ◽  
AR de L Musgrove ◽  
RL Walsh
Keyword(s):  
Kinetic Energy ◽  
Thermal Neutron ◽  
Neutron Emission ◽  
Total Kinetic Energy ◽  
Counting Method ◽  
Neutron Fission ◽  
Fragment Mass ◽  
Fission Fragments ◽  
Thermal Neutron Fission ◽  
The Mean

Measurements have been made of prompt neutron emission in the thermal neutron fission of 235 U and the mean neutron emission per fragment has been obtained for particular values of the fragment mass and total kinetic energy. A direct neutron counting method was employed and a comparison is made with data from previous experiments of this type.

scholarly journals Revisiting the Analysis of the Isochronous Mass Measurements of Uranium Fission Fragments at the ESR

2020 ◽  
Vol 227 ◽  
pp. 02012
Author(s):  
R. S. Sidhu ◽  
R. J. Chen ◽  
Yu. A Litvinov ◽  
Y. H. Zhang ◽  
Keyword(s):  
Experimental Data ◽  
Data Analysis ◽  
State Of The Art ◽  
Fission Products ◽  
Mass Measurements ◽  
Fission Fragments ◽  
Uranium Fission

The re-analysis of experimental data on mass measurements of ura- nium fission products obtained at the ESR in 2002 is discussed. State-of-the-art data analysis procedures developed for such measurements are employed.

scholarly journals Relativistic B-Spline R-Matrix Calculations for Electron Collisions with Ytterbium

Atoms ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 47
Author(s):  
Kathryn R. Hamilton ◽  
Klaus Bartschat ◽  
Oleg Zatsarinny
Keyword(s):  
Experimental Data ◽  
Electron Scattering ◽  
Cross Sections ◽  
Matrix Method ◽  
Model Potential ◽  
Electron Collisions ◽  
R Matrix ◽  
B Spline ◽  
Potential Approach

We have applied the full-relativistic Dirac B-Spline R-matrix method to obtain cross sections for electron scattering from ytterbium atoms. The results are compared with those obtained from a semi-relativistic (Breit-Pauli) model-potential approach and the few available experimental data.

SPALLATION YIELDS FROM HIGH ENERGY PROTON BOMBARDMENT OF HEAVY ELEMENTS

1957 ◽  
Vol 35 (1) ◽  
pp. 21-37 ◽  
Author(s):  
J. D. Jackson
Keyword(s):  
Cross Sections ◽  
High Energy ◽  
Heavy Elements ◽  
Collective Effects ◽  
Comparison With Experiment ◽  
Energy Proton ◽  
Stringent Test ◽  
Neutron Evaporation ◽  
Nuclear Processes ◽  
Mev Protons

The Monte Carlo calculations of McManus and Sharp (unpublished) for the prompt nuclear processes occurring upon bombardment of heavy elements by 400 Mev. protons are combined with a description of the subsequent neutron evaporation to determine spallation cross sections for comparison with experiment. The model employed is a schematic one which suppresses the detailed characteristics of individual nuclei, but gives the over-all behavior to be expected. Many-particle and collective effects such as alpha particle emission and fission are ignored. The computed cross sections are presented in a variety of different graphical forms which illustrate quantitatively the qualitative picture of high energy reactions first given by Serber (1947). The calculations are in general agreement with existing data when fission is not an important effect, but the agreement does not imply a very stringent test of the various features of the model.

HADRON SPIN-FLIP AMPLITUDE AND SLOPE OF DIFFERENTIAL CROSS-SECTIONS

1999 ◽  
Vol 14 (03) ◽  
pp. 223-230 ◽  
Author(s):  
O. V. SELYUGIN
Keyword(s):  
Experimental Data ◽  
Cross Sections ◽  
Differential Cross ◽  
Scattering Amplitude ◽  
Previous Analysis ◽  
Differential Cross Sections ◽  
Spin Flip ◽  
Flip Amplitude

A possibility to obtain restrictions of the magnitude of the elastic spin-flip hadron scattering amplitude from accurately measured experimental data on the differential cross-sections of elastic hadron–hadron scattering is shown. Appropriate estimations confirm the previous analysis of experimental data at [Formula: see text] GeV and a probable contribution of the hadron spin-flip amplitude.

Cross sections for d-3H neutron interactions with samarium isotopes

2016 ◽  
Vol 104 (8) ◽  
Author(s):  
Junhua Luo ◽  
Chunlei Wu ◽  
Li Jiang ◽  
Long He
Keyword(s):  
Experimental Data ◽  
Neutron Flux ◽  
Cross Sections ◽  
Theoretical Calculations ◽  
Nuclear Model ◽  
Activation Technique ◽  
Incident Neutron ◽  
Reaction Threshold ◽  
Talys 1.6 ◽  
The Cross

Abstract:The cross sections for (n,x) reactions on samarium isotopes were measured at (d-T) neutron energies of 13.5 and 14.8 MeV with the activation technique. Samples were activated along with Nb and Al monitor foils to determine the incident neutron flux. Theoretical calculations of excitation functions were performed using the nuclear model codes TALYS-1.6 and EMPIRE-3.2 Malta with default parameters, at neutron energies varying from the reaction threshold to 20 MeV. The results were discussed and compared with experimental data found in the literature. At neutron energies 13.5 and 14.8 MeV, the cross sections of the

Sign in / Sign up

Export Citation Format

Share Document