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.

THE THERMAL NEUTRON FISSION YIELDS OF U233

1961 ◽  
Vol 39 (3) ◽  
pp. 628-634 ◽  
Author(s):  
D. R. Bidinosti ◽  
D. E. Irish ◽  
R. H. Tomlinson
Keyword(s):  
Fission Product ◽  
Thermal Neutron ◽  
Mass Spectrometer ◽  
Isotope Dilution ◽  
Dilution Technique ◽  
Neutron Fission ◽  
Isotope Dilution Technique ◽  
Thermal Neutron Fission ◽  
Fission Yields

Using the mass spectrometer and isotope dilution technique, 27 cumulative fission yields from the thermal neutron fission of U233 along with 13 other fission product chains relative to each other have been determined. After normalization of the latter, values are obtained for all but seven fission decay chains whose yields are in excess of 0.5%.

THE CUMULATIVE FISSION YIELDS OF LIGHT MASS FRAGMENTS IN THE THERMAL NEUTRON FISSION OF Pu239

1959 ◽  
Vol 37 (8) ◽  
pp. 916-925 ◽  
Author(s):  
H. R. Fickel ◽  
R. H. Tomlinson
Keyword(s):  
Fission Product ◽  
Thermal Neutron ◽  
Mass Spectrometer ◽  
Isotope Dilution ◽  
Light Fragment ◽  
Neutron Fission ◽  
Fragment Mass ◽  
Thermal Neutron Fission ◽  
Fission Yields

The relative cumulative yields of 19 light mass fragments of rubidium, strontium, yttrium, zirconium, molybdenum, and ruthenium formed in the thermal neutron fission of Pu239 have been determined with a mass spectrometer using the isotope dilution technique.The yields of the fission product isotopes of these elements, together with the previously published relative yields of three krypton isotopes, have made possible the determination of the absolute yields of 22 light fragment mass chains.

THE RELATIVE ABUNDANCES OF NEODYMIUM AND SAMARIUM ISOTOPES IN THE THERMAL NEUTRON FISSION OF U235 AND U233

1955 ◽  
Vol 33 (5) ◽  
pp. 830-837 ◽  
Author(s):  
E. A. Melaika ◽  
M. J. Parker ◽  
J. A. Petruska ◽  
R. H. Tomlinson
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Neutron Capture ◽  
Natural Uranium ◽  
Fission Yield ◽  
Yield Data ◽  
Neutron Fission ◽  
Thermal Neutron Fission ◽  
The Cross ◽  
Fission Yields

The relative fission yields of neodymium and samarium isotopes have been measured with a mass spectrometer for samples of natural uranium and U233 that had been irradiated with moderated neutrons. The cross sections for neutron capture by Sm149 and Sm151 have been determined to be 66,200 ± 2500 barns and 12,000 barns respectively, relative to the cross section of a B10 monitor. The half-lives of Pm147 and Sm151 have been evaluated to be 2.52 ± 0.08 yr. and ~93 yr., respectively, from samarium fission yield data for samples differing in age by seven years.

CUMULATIVE YIELDS OF LIGHT FRAGMENTS IN U235 THERMAL NEUTRON FISSION

1962 ◽  
Vol 40 (8) ◽  
pp. 1017-1026 ◽  
Author(s):  
H. Farrar ◽  
H. R. Fickel ◽  
R. H. Tomlinson
Keyword(s):  
Thermal Neutron ◽  
Yield Curve ◽  
Mass Spectrometric Study ◽  
Detailed Examination ◽  
Mass Region ◽  
Mass Yield ◽  
Neutron Fission ◽  
Molybdenum Isotopes ◽  
Thermal Neutron Fission ◽  
Fission Yields

A mass spectrometric study of the relative yields of the strontium, yttrium, zirconium, and molybdenum isotopes formed in the thermal neutron fission of U235 has made possible a detailed examination of structure of the light mass region of the mass–yield curve. The relative yields of this work have been normalized to 5.77% for Sr90, and when literature and extrapolated values are taken for the remaining chains, the fission yields total 100.8%.

THE FISSION YIELDS OF THE CESIUM ISOTOPES FORMED IN THE THERMAL NEUTRON FISSION OF U235 AND THE NEUTRON ABSORPTION CROSS SECTION OF Xe135

1955 ◽  
Vol 33 (11) ◽  
pp. 640-649 ◽  
Author(s):  
J. A. Petruska ◽  
E. A. Melaika ◽  
R. H. Tomlinson
Keyword(s):  
Thermal Neutron ◽  
Cross Section ◽  
Isotope Dilution ◽  
Absorption Cross Section ◽  
Neutron Absorption ◽  
Absorption Cross ◽  
Neutron Fission ◽  
Thermal Neutron Fission ◽  
Fission Yields ◽  
Neutron Absorption Cross Section

The absolute fission yields of the cesium isotopes occurring in the thermal neutron fission of U235 have been determined with a mass spectrometer using isotope dilution techniques. Values of 6.59%, 6.41%, and 6.15% have been obtained for the yields of Cs133, Cs135, and Cs137 respectively. The neutron absorption cross section of Xe135 has also been measured to be 866 times greater than that of B10 for a Maxwellian distribution of neutron velocities corresponding to a neutron temperature of 57 °C. This ratio gives a thermal neutron absorption cross section of 3.47 × 106 barns for Xe135 assuming it is a 1/ν detector.

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