SOME CUMULATIVE YIELDS OF ISOTOPES FORMED IN THE THERMAL NEUTRON FISSION OF Pu239

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.

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.


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%.


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.


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.


1964 ◽  
Vol 42 (11) ◽  
pp. 2063-2079 ◽  
Author(s):  
H. Farrar ◽  
W. B. Clarke ◽  
H. G. Thode ◽  
R. H. Tomlinson

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.


1956 ◽  
Vol 34 (3) ◽  
pp. 233-237 ◽  
Author(s):  
A. T. Blades ◽  
W. H. Fleming ◽  
H. G. Thode

The ratio of the yield of Kr86 to the yield of Xe134 in U235 fission is 0.257 ±.005 determined by isotope dilution techniques. The corresponding yield ratio of total xenon to total krypton in the thermal neutron fission of U235 is 5.52 ±.10.


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