Relative Yields of Stable Cadmium Isotopes in Neutron Induced Fission

1975 ◽  
Vol 53 (8) ◽  
pp. 775-785 ◽  
Author(s):  
J. R. De Laeter ◽  
H. G. Thode
Keyword(s):  
Mass Spectrometry ◽  
Fine Structure ◽  
Mass Range ◽  
Mass Yield ◽  
Fission Event ◽  
Low Mass ◽  
Induced Fission ◽  
Symmetric Fission ◽  
Fission Yields ◽  
Mass Yield Distribution

The relative fission yields of the five stable isotopes of cadmium (111Cd, 112Cd, 113Cd, 114Cd, and 116Cd) produced in the thermal and epicadmium fission of 233U and 235U and the epicadmium fission of 238U have been measured by solid source mass spectrometry. Nanogram sized samples of fission product cadmium were analyzed to give a range of yields on the low mass side of symmetric fission. The results indicate that the mass yield distribution for thermal induced fission is relatively flat within five mass units of the valley of symmetry. The epicadmium induced fission results show enhanced yields at mass 111, the degree of enrichment depending on the mass of the fissioning nucleus. The only significant fine structure occurs at mass 113 for the epicadmium induced fission of 235U. Although less certain, there is also a suggestion of a depressed yield at mass 113 for thermal neutron induced fission of 235U as well. No evidence of a symmetric peak was observed in any of the data. The absence of significant fine structure in this mass range suggests that the average number of neutrons emitted per fission event varies fairly smoothly with mass.

THE CUMULATIVE YIELDS OF THE KRYPTON AND XENON ISOTOPES PRODUCED IN THE FAST NEUTRON FISSION OF Th232

1957 ◽  
Vol 35 (8) ◽  
pp. 969-979 ◽  
Author(s):  
T. J. Kennett ◽  
H. G. Thode
Keyword(s):  
Fine Structure ◽  
Fast Neutron ◽  
Isotope Dilution ◽  
Yield Curve ◽  
Mass Yield ◽  
Neutron Fission ◽  
Xenon Isotopes ◽  
Induced Fission ◽  
The Absolute ◽  
Fission Yields

The relative fission yields for mass chains ending in stable krypton and xenon isotopes have been measured for the fast neutron-induced fission of Th232. Isotope dilution techniques were used to determine the krypton/xenon ratio to assist in obtaining the absolute fission yields for these mass chains. The absolute yields were determined by the use of two methods, both giving results which were in excellent agreement. The fine structure observed for the Th232 mass–yield curve is compared with that of heavier fissile nuclides.

THE FISSION YIELDS OF THE STABLE AND LONG-LIVED ISOTOPES OF XENON, CESIUM, AND KRYPTON IN NEUTRON FISSION OF U233

1954 ◽  
Vol 32 (8) ◽  
pp. 522-529 ◽  
Author(s):  
W. Fleming ◽  
R. H. Tomlinson ◽  
H. G. Thode
Keyword(s):  
Fine Structure ◽  
Mass Spectrometer ◽  
Yield Curve ◽  
Closed Shell ◽  
Mass Range ◽  
The Other ◽  
Mass Yield ◽  
Fission Yield ◽  
Neutron Fission ◽  
Fission Yields

The fission yields of Xe131, Xe132, Xe134, Xe136, Cs133, Cs135, Cs137, Kr83, Kr84, 10.27 year Kr85, and Kr86 in the neutron fission of U233 have been determined by mass spectrometer methods. The very pronounced fine structure in the mass yield curve in the mass range 131 to 137 found in U235 fission does not occur in the fission of U233. This disappearance of fine structure would not have been predicted by any of the mechanisms which have been suggested to explain the fine structure in U235 fission. The fission yield of the 10.27 year isomer of Kr85 relative to the other krypton isotopes is considerably higher in U233 fission than in U235 fission, indicating some fine structure in this mass range which may be related to the closed shell of 50 neutrons.

scholarly journals From fission yield measurements to evaluation: status on statistical methodology for the covariance question

2018 ◽  
Vol 4 ◽  
pp. 26 ◽  
Author(s):  
Brieuc Voirin ◽  
Grégoire Kessedjian ◽  
Abdelaziz Chebboubi ◽  
Sylvain Julien-Laferrière ◽  
Olivier Serot
Keyword(s):  
Statistical Tests ◽  
Fission Products ◽  
Experimental Program ◽  
Mass Yield ◽  
Statistical Methodology ◽  
Fission Yield ◽  
Fission Process ◽  
Induced Fission ◽  
Entropy Criterion ◽  
Fission Yields

Studies on fission yields have a major impact on the characterization and the understanding of the fission process and are mandatory for reactor applications. Fission yield evaluation represents the synthesis of experimental and theoretical knowledge to perform the best estimation of mass, isotopic and isomeric yields. Today, the output of fission yield evaluation is available as a function of isotopic yields. Without the explicitness of evaluation covariance data, mass yield uncertainties are greater than those of isotopic yields. This is in contradiction with experimental knowledge where the abundance of mass yield measurements is dominant. These last years, different covariance matrices have been suggested but the experimental part of those are neglected. The collaboration between the LPSC Grenoble and the CEA Cadarache starts a new program in the field of the evaluation of fission products in addition to the current experimental program at Institut Laue-Langevin. The goal is to define a new methodology of evaluation based on statistical tests to define the different experimental sets in agreement, giving different solutions for different analysis choices. This study deals with the thermal neutron induced fission of 235U. The mix of data is non-unique and this topic will be discussed using the Shannon entropy criterion in the framework of the statistical methodology proposed.

Cumulative yields of stable and long-lived isotopes of tin in neutron-induced fission

1983 ◽  
Vol 61 (11) ◽  
pp. 1490-1497 ◽  
Author(s):  
K. J. R. Rosman ◽  
J. R. De Laeter ◽  
J. W. Boldeman ◽  
H. G. Thode
Keyword(s):  
Stable Isotopes ◽  
Fine Structure ◽  
Fission Product ◽  
Mass Spectrometer ◽  
Smooth Curve ◽  
Mass Region ◽  
Neutron Fission ◽  
Source Mass ◽  
Induced Fission ◽  
Fission Yields

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.

THE ABSOLUTE FISSION YIELDS OF TWENTY-EIGHT MASS CHAINS IN THE THERMAL NEUTRON FISSION OF U235

1955 ◽  
Vol 33 (11) ◽  
pp. 693-706 ◽  
Author(s):  
J. A. Petruska ◽  
H. G. Thode ◽  
R. H. Tomlinson
Keyword(s):  
Fine Structure ◽  
Isotope Dilution ◽  
Yield Curve ◽  
Mass Yield ◽  
Absolute Accuracy ◽  
Neutron Fission ◽  
Thermal Neutron Fission ◽  
The Absolute ◽  
Fission Yields ◽  
Better Than

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.

scholarly journals Relative Yields of Stable Tellurium Isotopes in Neutron-induced Fission

1982 ◽  
Vol 35 (4) ◽  
pp. 385 ◽  
Author(s):  
JR de Laeter ◽  
KJR Rosman ◽  
JW Boldeman
Keyword(s):  
Mass Spectrometry ◽  
Yield Curve ◽  
Mass Range ◽  
Neutron Fission ◽  
Significant Depression ◽  
Isotopic Abundances ◽  
Thermal Neutron Fission ◽  
First Time ◽  
Fission Yields ◽  
Good Agreement

The relative isotopic abundances of four isotopes of tellurium (125, 126, 128 and 130) produced in the thermal neutron fission of 233U and 23SU have been measured for the first time by solid source mass spectrometry. Samples of 233U and 23SU were irradiated in a reactor and chemically separated by ion exchange techniques to permit nanogram-sized samples of fission product tellurium to be analysed mass spectrometrically. The results for 23SU are in good agreement with published radiometric values, whereas our results for 233U are the first experimental measurements in this mass range. The cumulative fission yields determined by mass spectrometry for ruthenium, palladium, cadmium, tin and tellurium show a smooth mass distribution in the symmetric region for both 233U and 235U, except for a significant depression in the yield curve in the range 111-14.

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