Systematic behavior of mass-yield curves in low-energy fission of actinides

1990 ◽  
Vol 142 (1) ◽  
pp. 231-251 ◽  
Author(s):  
H. Nakahara ◽  
T. Ohtsuki
1991 ◽  
Vol 44 (4) ◽  
pp. 1405-1423 ◽  
Author(s):  
T. Ohtsuki ◽  
Y. Nagame ◽  
K. Tsukada ◽  
N. Shinohara ◽  
S. Baba ◽  
...  

1989 ◽  
Vol 40 (5) ◽  
pp. 2144-2153 ◽  
Author(s):  
T. Ohtsuki ◽  
Y. Hamajima ◽  
K. Sueki ◽  
H. Nakahara ◽  
Y. Nagame ◽  
...  

1976 ◽  
Vol 29 (3) ◽  
pp. 125 ◽  
Author(s):  
JL Cook ◽  
EK Rose ◽  
GD Trimble

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.


2001 ◽  
Vol 89 (11-12) ◽  
Author(s):  
Y. Nagame ◽  
Y.L. Zhao ◽  
I. Nishinaka ◽  
S. Goto ◽  
D. Kaji ◽  
...  

Characteristics of nuclear deformation properties at scission of two fission modes, symmetric and asymmetric, are reviewed. Existence of two kinds of scission configurations associated with the symmetric and asymmetric fission modes is pointed out: elongated and compact configurations. Each symmetric and asymmetric scission property is discussed in terms of shape elongation evaluated from fragment total kinetic energy (TKE). Fragment deformation at scission is also discussed based on neutron multiplicity data. From the systematic study of the scission properties in a wide range of actinide fission, the bimodal fission observed in spontaneous fission (SF) of the heavy actinides is interpreted as the result of the presence of the two fission paths of the ordinary asymmetric mode and a strongly shell-influenced symmetric one. The correlation between the fragment shell structures and the asymmetric mass-yield curves is described.


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.


1990 ◽  
Vol 42 (5) ◽  
pp. 2005-2008 ◽  
Author(s):  
P. D. Cottle ◽  
M. A. Kennedy ◽  
K. A. Stuckey

1984 ◽  
Vol 138 (5-6) ◽  
pp. 353-356 ◽  
Author(s):  
X. Campi ◽  
J. Desbois ◽  
E. Lipparini

2017 ◽  
Vol 96 (6) ◽  
Author(s):  
L. A. Riley ◽  
M. L. Agiorgousis ◽  
T. R. Baugher ◽  
D. Bazin ◽  
R. L. Blanchard ◽  
...  

Author(s):  
N. Feather

SynopsisThe recent suggestion (Feather 1974) that the short-range α-particles of fission are emitted predominantly from post-neutron-emission fragments in the mass-number range 140 to 145 is shown to have implications in relation to the fine-structure of the mass-yield curve. An examination of the mass-yield curves of Unik et al. (1973) discloses, in many of them, a fine-structure feature of the type predicted.


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