scholarly journals Fission Product Mass Yield Curves and Their Energy Dependence

1976 ◽  
Vol 29 (3) ◽  
pp. 125 ◽  
Author(s):  
JL Cook ◽  
EK Rose ◽  
GD Trimble
Keyword(s):  
Fission Product ◽  
Saddle Point ◽  
Empirical Analysis ◽  
Energy Dependence ◽  
Cross Sections ◽  
Mass Yield ◽  
Neutron Fission ◽  
Yield Curves ◽  
Nuclear Temperature ◽  
Better Than

It has been found that the mass yield curves for 232Th, 233U, 235U, 238U and 239pU neutron fission can be fitted, with an accuracy of better than 20 %, by the superposition of two pairs of asymmetric gaussian curves and a single symmetric gaussian curve. The parameters of the fit have been investigated as a function of the nuclear temperature at the saddle point of the fissioning compound nucleus, and the widths and positions are found to vary linearly with this temperature. In addition, broad peaks are found in the weights of the gaussians, the weights being related to partial fission cross sections. This empirical analysis has been compared with the predictions of the Nix (1969) model of fission and deficiencies in the existing theory are discussed.

THE ABSOLUTE FISSION YIELDS OF TWENTY-EIGHT MASS CHAINS IN THE THERMAL NEUTRON FISSION OF U235

1955 ◽  
Vol 33 (11) ◽  
pp. 693-706 ◽  
Author(s):  
J. A. Petruska ◽  
H. G. Thode ◽  
R. H. Tomlinson
Keyword(s):  
Fine Structure ◽  
Isotope Dilution ◽  
Yield Curve ◽  
Mass Yield ◽  
Absolute Accuracy ◽  
Neutron Fission ◽  
Thermal Neutron Fission ◽  
The Absolute ◽  
Fission Yields ◽  
Better Than

Twenty-eight absolute fission yields totalling 78% of the heavy and 16% of the light fragments have been determined using the mass spectrometer and isotope dilution techniques. The precision of the values obtained is in most cases better than 2% and the absolute accuracy is estimated to be about 3%. Fine structure in the mass–yield curve is discussed in terms of structural preference and various chain branching mechanisms.

CUMULATIVE YIELDS OF THE HEAVY FRAGMENTS IN THE THERMAL-NEUTRON FISSION OF 241Pu

1964 ◽  
Vol 42 (11) ◽  
pp. 2063-2079 ◽  
Author(s):  
H. Farrar ◽  
W. B. Clarke ◽  
H. G. Thode ◽  
R. H. Tomlinson
Keyword(s):  
Fine Structure ◽  
Thermal Neutron ◽  
Isotope Dilution ◽  
Yield Curve ◽  
Mass Spectrometric ◽  
Mass Yield ◽  
General Shape ◽  
Neutron Fission ◽  
Yield Curves ◽  
Thermal Neutron Fission

The relative yields of isotopes of xenon, cesium, barium, cerium, neodymium, and samarium formed by the thermal neutron fission of 241Pu have been obtained by mass spectrometric methods. The relative yields of the elements were normalized by means of the isotope dilution and isobaric techniques, and absolute cumulative yields were determined by summing the relative yields to 100%. The curve obtained for 241Pu is compared with other mass–yield curves. The general shape of this mass–yield curve is similar to that for 239Pu; yet the fine structure shows greater similarity to that for 235U thermal-neutron fission.

Relative yields of stable tin isotopes in neutron-induced fission

1969 ◽  
Vol 47 (13) ◽  
pp. 1409-1414 ◽  
Author(s):  
J. R. de Laeter ◽  
H. G. Thode
Keyword(s):  
High Sensitivity ◽  
Smooth Curve ◽  
Natural Uranium ◽  
Tandem Mass ◽  
Mass Yield ◽  
Neutron Fission ◽  
Yield Curves ◽  
Fuel Rod ◽  
Induced Fission ◽  
Symmetric Fission

A tandem mass spectrometer of high sensitivity has been used to measure the relative yields of the six stable isotopes of tin (117Sn, 118Sn, 119Sn, 120Sn, 122Sn, and 124Sn) and the long-lived isotope 126Sn, produced in the thermal- and fast-neutron fission of 233U and in a reactor fuel rod of natural uranium. Samples of the order of 10−9 g of tin were extracted and analyzed to give a range of yields in the region of symmetric fission. The results show that the mass yield curves in the region of symmetric fission covered by the stable tin isotopes are almost identical for the three irradiations. Furthermore, a smooth curve can be drawn through the yield points for the seven isotopes of tin and there is no evidence of "fine structure" or sharp depression in the curves in this region as has been predicted.

THE FISSION YIELDS OF Ba139 AND Ba140 IN NEUTRON FISSION OF U235 AND U238

1947 ◽  
Vol 25b (4) ◽  
pp. 364-370 ◽  
Author(s):  
W. E. Grummitt ◽  
L. Yaffe ◽  
J. Guéron ◽  
G. Wilkinson
Keyword(s):  
Fission Product ◽  
Thermal Neutron ◽  
Cross Sections ◽  
Radiative Capture ◽  
Neutron Fission ◽  
Fast Fission ◽  
Naturally Occurring ◽  
Thermal Neutron Fission ◽  
The Cross ◽  
Fission Yields

The fission yields for Ba139 and Ba140 for thermal neutron fission of U235 and fast fission of U238 have been measured using naturally occurring uranium. This was accomplished by comparing the barium fission product activities with the U239 formed in radiative capture. With these data the fission yields were calculated from known values of the cross-sections for thermal fission and capture in uranium and were found to be 6.1% and 5.6% for Ba139 and Ba140, respectively, for thermal fission and 5.1% and 4.2% for Ba139 and Ba140, respectively, for fast fission. The contribution of resonance fission to the thermal neutron effect has been shown to be less than 5% in the irradiation arrangement used.

scholarly journals Systematic study of proton-induced spallation reactions with the Constrained Molecular Dynamics (CoMD) model

2019 ◽  
Vol 24 ◽  
pp. 42
Author(s):  
A. Assimakopoulou ◽  
G. A. Souliotis ◽  
A. Bonasera ◽  
M. Veselsky
Keyword(s):  
Molecular Dynamics ◽  
Cross Section ◽  
Cross Sections ◽  
Proton Energy ◽  
Fission Cross Section ◽  
Mass Yield ◽  
Yield Curves ◽  
High Energies ◽  
Spallation Reactions ◽  
Before And After

Proton – induced spallation reactions on 238U, 208Pb, 181Ta and 197Au targets at high energies were studied and investigated using the microscopic Contrained Molecular Dynamics (CoMD) model. Total fission cross sections, the ratio fission cross section to residue cross section, mean kinetic energy of fission fragments, mass yield curves and the number of nucleons emitted, before and after scission, as well as the total nucleon multiplicity were calculated using the CoMD model and compared with experimental data from the literature. Some of our calculations showed satisfactory agreement with available experimental data.The calculations of cross sections and the ratio fission cross section to residue cross section as a function of the proton energy gave us the opportunity to estimate observables for unmeasured nuclides.

Bargaining, Yield Curves, and Wage Settlements: An Empirical Analysis

1974 ◽  
Vol 82 (2, Part 1) ◽  
pp. 303-313 ◽  
Author(s):  
Yochanan Comay ◽  
Arie Melnik ◽  
Abraham Subotnik
Keyword(s):  
Empirical Analysis ◽  
Yield Curves

scholarly journals A note on the relations between elastic and inelastic interactions and increasing ratio σel(s)/σtot(s) at the LHC

2019 ◽  
Vol 34 (32) ◽  
pp. 1950259 ◽  
Author(s):  
S. M. Troshin ◽  
N. E. Tyurin
Keyword(s):  
Elastic Scattering ◽  
Energy Dependence ◽  
Impact Parameter ◽  
Cross Sections ◽  
Parameter Dependence ◽  
Slope Parameter ◽  
Short Notice ◽  
Inelastic Interactions ◽  
The Impact ◽  
Mode A

We comment briefly on relations between the elastic and inelastic cross-sections valid for the shadow and reflective modes of the elastic scattering. Those are based on the unitarity arguments. It is shown that the redistribution of the probabilities of the elastic and inelastic interactions (the form of the inelastic overlap function becomes peripheral) under the reflective scattering mode can lead to increasing ratio of [Formula: see text] at the LHC energies. In the shadow scattering mode, the mechanism of this increase is a different one, since the impact parameter dependence of the inelastic interactions probability is central in this mode. A short notice is also given on the slope parameter and the leading contributions to its energy dependence in both modes.

Energy dependence of 12C+12C single-neutron transfer cross sections

1988 ◽  
Vol 203 (4) ◽  
pp. 345-348 ◽  
Author(s):  
J.S. Winfield ◽  
Sam M. Austin ◽  
G.M. Crawley ◽  
C. Djalali ◽  
C.A. Ogilvie ◽  
...  
Keyword(s):  
Energy Dependence ◽  
Cross Sections ◽  
Neutron Transfer ◽  
Single Neutron

Photoablösung von Elektronen bei einigen stabilen negativen Ionen

1970 ◽  
Vol 25 (5) ◽  
pp. 621-626 ◽  
Author(s):  
D. Feldmann
Keyword(s):  
Cross Sections ◽  
Negative Ions ◽  
Better Than

Photodetaehment of electrons from some stable negative ions has been measured. Cross sections of about 10-17 cm2, and the following minimal detachment energies were found: H-: 0.776 eV, C-*: < 0.5 eV, CH-: 0.74 eV, C2- : 3.54 eV, C2H- : 3.73 eV, SO-: 1.09 eV, and SO-: 1.0 eV with an accuracy better than + 0.05 eV.

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