THE RATIO OF THE DIRECT TO THE CUMULATIVE YIELD OF 135Xe IN THE THERMAL NEUTRON FISSION OF 233U, 235U, 239Pu, AND 241pu

1966 ◽  
Vol 44 (1) ◽  
pp. 237-246 ◽  
Author(s):  
A. Okazaki ◽  
W. H. Walker ◽  
C. B. Bigham
Keyword(s):  
Neutron Flux ◽  
Thermal Neutron ◽  
Decay Curve ◽  
Time Shift ◽  
Cumulative Yield ◽  
Β Decay ◽  
Neutron Fission ◽  
Short Irradiation ◽  
Thermal Neutron Fission ◽  
Γ Ray

The ratio of the direct to cumulative yields of 135Xe produced in thermal neutron fission has been determined by measuring the growth and decay of this nuclide in irradiated 233U, 235U, 239Pu, and 241Pu. After a short irradiation in a low neutron flux, the amount of 135Xe increases and reaches a maximum at about 11 hours after the end of the irradiation. The direct yield of 135Xe modifies the time this maximum is reached. The ratio of the direct to cumulative yields was determined by measuring the time shift of the growth and decay curve. The amount of 135Xe was measured as a function of time after the end of irradiation by counting the 249-keV γ ray accompanying the β decay of 135Xe with a lithium-drifted germanium-diode spectrometer. The ratio of the direct to the cumulative yield was found to be 0.195 ± 0.016, 0.044 ± 0.017, 0.162 ± 0.025, and 0.070 ± 0.040 for 233U, 235U, 239Pu, and 241Pu fission respectively.

scholarly journals ABSOLUTE THERMAL NEUTRON FISSION YIELDS OF U233

1960 ◽  
Vol 38 (3) ◽  
pp. 421-438 ◽  
Author(s):  
D. C. Santry ◽  
L. Yaffe
Keyword(s):  
Neutron Flux ◽  
Thermal Neutron ◽  
Flux Monitor ◽  
Neutron Fission ◽  
Neutron Flux Monitor ◽  
Chemical Separations ◽  
Thermal Neutron Fission ◽  
Γ Ray ◽  
The Absolute ◽  
Fission Yields

The absolute fission yields of 22 nuclides formed in the thermal neutron fission of U233 have been measured radiochemically. Disintegration rates were measured by 4π β-proportional counting techniques. The identity of each nuclide was established by chemical separations and decay characteristics as determined by 4π β-counting and γ-ray scintillation spectrometry. The reaction Co59(n, γ)Co60 was used as a neutron flux monitor. Yields were calculated on the basis of [Formula: see text]

scholarly journals Yields of products in the spontaneous fission of 252Cf by direct γ-ray spectroscopy

1983 ◽  
Vol 61 (4) ◽  
pp. 649-651 ◽  
Author(s):  
L. Toppare ◽  
H. N. Erten ◽  
N. K. Aras
Keyword(s):  
Fine Structure ◽  
Thermal Neutron ◽  
Spontaneous Fission ◽  
Graphical Method ◽  
Spectroscopy Technique ◽  
Neutron Fission ◽  
Fragment Mass ◽  
Thermal Neutron Fission ◽  
Γ Ray

Yields of products both in the light and heavy sides in the spontaneous fission of 252Cf were measured by direct γ-ray spectroscopy technique. By suitably choosing collection, cooling, and counting times, it was possible to observe products with half-lives between 1 min and 1 h. A definite fine structure, as observed in the case of thermal neutron fission of 235U and 239Pu, was not observed. A graphical method was utilized to obtain the number of neutrons as a function of fragment mass using cumulative chain yields.

Independent Yields of Mass-135 Xenons in the Thermal Neutron Fission of 233U, 235U,239Pu, and 241Pu

1971 ◽  
Vol 49 (7) ◽  
pp. 785-803 ◽  
Author(s):  
R. C. Hawkings ◽  
W. J. Edwards ◽  
W. J. Olmstead
Keyword(s):  
Fission Product ◽  
Thermal Neutron ◽  
Rare Gas ◽  
Neutron Fission ◽  
Thermal Neutron Fission ◽  
Γ Ray ◽  
Gas Fractions

The ratio of the independent yield of 135Xe to the cumulative chain yield of 135I in thermal neutron fission of 233U, 235U, 239Pu, and 241Pu has been measured using radiochemical techniques. 135Xe and 135Xem were recovered quantitatively after short irradiations and compared with 135Xe grown from 135I in the same sample. Corrections were applied for interference from other fission-product gases in the NaI(Tl) γ-ray spectrometry of the rare gas fractions. If the independent yield for 135Xem is assumed to be zero, the ratio of the independent yield of 135Xe to the cumulative chain yield to 135I is found to be 0.2790 ± 0.0069 for 233U, 0.0357 ± 0.0019 for 235U, 0.1782 ± 0.0023 for 239Pu, and 0.0332 ± 0.0016 for 241Pu.The ratio of the cumulative chain yield to 135I for thermal fission of 239Pu to that for 241Pu was found to be 0.966 ± 0.054.

Ranges of shielded nuclides from thermal-neutron fission

1969 ◽  
Vol 47 (21) ◽  
pp. 2371-2385 ◽  
Author(s):  
H. Nakahara ◽  
J. W. Harvey ◽  
G. E. Gordon
Keyword(s):  
Monte Carlo ◽  
Thermal Neutron ◽  
Neutron Emission ◽  
Fission Products ◽  
Energy Transformation ◽  
Neutron Fission ◽  
Monte Carlo Calculations ◽  
Neighboring Chain ◽  
Thermal Neutron Fission ◽  
Γ Ray

Average ranges in Al of shielded nuclides 86Rb and 136Cs and several chain-yield species from thermal-neutron fission of 233U and 235U have been measured. The values obtained (in mg/cm2 Al) are, for 233U: 86Rb, 3.88 ± 0.04; 136CS, 2.80 ± 0.01; and for 235U: 86Rb, 3.76 ± 0.03; 136Cs, 2.81 ± 0.01. A range–energy transformation was used to determine average kinetic energies [Formula: see text] of the secondary fragments. In agreement with previous work, the shielded nuclides are found to have smaller [Formula: see text] values than neighboring chain-yield species. The deficits of [Formula: see text] are, for 233U, 4 and 8 MeV, and for 235U, 8 and 10 MeV, respectively, for 86Rb and 136Cs. Most of the range experiments were done with the thick-catcher method followed by conventional radiochemical treatment of the catcher foils. Ranges of 20 products from 233U were determined in preliminary experiments in which gross γ-ray spectra of fission products in the catcher foils were observed with a Ge(Li) detector. The kinetic-energy deficits of the shielded species are interpreted by Monte Carlo calculations of prompt-neutron emission.

Energy Distribution of Mass-97 Fission Fragments from Thermal-Neutron Fission of Uranium-235

1956 ◽  
Vol 104 (4) ◽  
pp. 1046-1053 ◽  
Author(s):  
Bernard L. Cohen ◽  
Anna Foner Cohen ◽  
Charles D. Coley
Keyword(s):  
Energy Distribution ◽  
Thermal Neutron ◽  
Neutron Fission ◽  
Fission Fragments ◽  
Thermal Neutron Fission

Angular correlation of neutrons from thermal-neutron fission of 235U

1978 ◽  
Vol 78 (5) ◽  
pp. 564-567 ◽  
Author(s):  
C.B. Franklyn ◽  
C. Hofmeyer ◽  
D.W. Mingay
Keyword(s):  
Thermal Neutron ◽  
Angular Correlation ◽  
Neutron Fission ◽  
Thermal Neutron Fission
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