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

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%.

1959 ◽  
Vol 37 (8) ◽  
pp. 916-925 ◽  
Author(s):  
H. R. Fickel ◽  
R. H. Tomlinson

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.


1955 ◽  
Vol 33 (11) ◽  
pp. 640-649 ◽  
Author(s):  
J. A. Petruska ◽  
E. A. Melaika ◽  
R. H. Tomlinson

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.


1956 ◽  
Vol 34 (3) ◽  
pp. 227-232 ◽  
Author(s):  
D. M. Wiles ◽  
J. A. Petruska ◽  
R. H. Tomlinson

The relative yields of the isotopes of cesium, cerium, neodymium, and samarium produced by the thermal neutron fission of Pu239 have been determined with a mass spectrometer. Preliminary values of the absolute yields of 16 isotopes of these elements together with four yields of the xenon isotopes have been assigned by means of isotope dilution techniques.


1978 ◽  
Vol 56 (10) ◽  
pp. 1340-1352 ◽  
Author(s):  
Masako Shima ◽  
H. G. Thode ◽  
R. H. Tomlinson

The relative cumulative yields of nine stable and long-lived isotopes of ruthenium and palladium (masses 101 to 110) produced in the thermal neutron fission of 233U and in the thermal and epicadmium neutron fission of 235U and 239Pu have been measured using a solid source mass spectrometer and isotope dilution techniques. Absolute yields of these isotopes for the thermal neutron fission of 233U, 235U, and 239Pu are obtained using normalization procedures. These yields provide the first experimentally determined yields of the palladium masses 105, 106, 107, 108, and 110.In the thermal fission of 233U and 235U the ruthenium isotope yields obtained are in general agreement with previously determined values, although discrepancies exist of the order of 10% at masses 103, 104, and 106 for thermal fission of 235U.A plot of the ruthenium and palladium isotope mass yields together with the previously determined yields for the cadmium and tin isotopes indicate a significant depression in the mass yield curve at masses 111 and 114 for 233U and 235U thermal fission, respectively. In the 235U epicadmium fission, yields at even mass numbers are relatively higher than those at odd numbers, resulting in a zigzag yield curve in the 101 to 110 mass region.


1947 ◽  
Vol 25b (4) ◽  
pp. 364-370 ◽  
Author(s):  
W. E. Grummitt ◽  
L. Yaffe ◽  
J. Guéron ◽  
G. Wilkinson

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.


1966 ◽  
Vol 44 (5) ◽  
pp. 1011-1019 ◽  
Author(s):  
J. W. Harvey ◽  
W. B. Clarke ◽  
H. G. Thode ◽  
R. H. Tomlinson

The relative cumulative yields for isotopes of the elements krypton, strontium, xenon, cesium, cerium, and neodymium formed in the thermal-neutron fission of 229Th have been determined by mass spectrometric techniques. Normalization of the relative yields by means of the isotope dilution and isobaric techniques has allowed estimates to be made of the absolute cumulative yields of the heavy-mass group by forcing the sum of the yields to total 100%.


1983 ◽  
Vol 61 (11) ◽  
pp. 1490-1497 ◽  
Author(s):  
K. J. R. Rosman ◽  
J. R. De Laeter ◽  
J. W. Boldeman ◽  
H. G. Thode

The relative cumulative fission yields of the six stable isotopes of tin (117Sn,118Sn, 119Sn, 120Sn, 122Sn, and 124Sn) and the long-lived isotope 126Sn have been measured in the thermal and epicadium neutron fission of 233U and 235U, and the epicadium neutron fission of 238U. Nanogram-sized fission product tin samples were extracted from irradiated uranium samples and analyzed in a solid source mass spectrometer. In each case a smooth curve can be drawn through the yield points of the seven isotopes of tin. There is, therefore, no evidence of "fine structure" in the 117 ≤ A ≤ 126 portion of the symmetric mass region.


1955 ◽  
Vol 33 (11) ◽  
pp. 693-706 ◽  
Author(s):  
J. A. Petruska ◽  
H. G. Thode ◽  
R. H. Tomlinson

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.


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