Relative yields of stable tin isotopes in neutron-induced fission

1969 ◽  
Vol 47 (13) ◽  
pp. 1409-1414 ◽  
Author(s):  
J. R. de Laeter ◽  
H. G. Thode
Keyword(s):  
High Sensitivity ◽  
Smooth Curve ◽  
Natural Uranium ◽  
Tandem Mass ◽  
Mass Yield ◽  
Neutron Fission ◽  
Yield Curves ◽  
Fuel Rod ◽  
Induced Fission ◽  
Symmetric Fission

A tandem mass spectrometer of high sensitivity has been used to measure the relative yields of the six stable isotopes of tin (117Sn, 118Sn, 119Sn, 120Sn, 122Sn, and 124Sn) and the long-lived isotope 126Sn, produced in the thermal- and fast-neutron fission of 233U and in a reactor fuel rod of natural uranium. Samples of the order of 10−9 g of tin were extracted and analyzed to give a range of yields in the region of symmetric fission. The results show that the mass yield curves in the region of symmetric fission covered by the stable tin isotopes are almost identical for the three irradiations. Furthermore, a smooth curve can be drawn through the yield points for the seven isotopes of tin and there is no evidence of "fine structure" or sharp depression in the curves in this region as has been predicted.

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.

scholarly journals Fission Product Mass Yield Curves and Their Energy Dependence

1976 ◽  
Vol 29 (3) ◽  
pp. 125 ◽  
Author(s):  
JL Cook ◽  
EK Rose ◽  
GD Trimble
Keyword(s):  
Fission Product ◽  
Saddle Point ◽  
Empirical Analysis ◽  
Energy Dependence ◽  
Cross Sections ◽  
Mass Yield ◽  
Neutron Fission ◽  
Yield Curves ◽  
Nuclear Temperature ◽  
Better Than

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.

CUMULATIVE YIELDS OF THE HEAVY FRAGMENTS IN THE THERMAL-NEUTRON FISSION OF 241Pu

1964 ◽  
Vol 42 (11) ◽  
pp. 2063-2079 ◽  
Author(s):  
H. Farrar ◽  
W. B. Clarke ◽  
H. G. Thode ◽  
R. H. Tomlinson
Keyword(s):  
Fine Structure ◽  
Thermal Neutron ◽  
Isotope Dilution ◽  
Yield Curve ◽  
Mass Spectrometric ◽  
Mass Yield ◽  
General Shape ◽  
Neutron Fission ◽  
Yield Curves ◽  
Thermal Neutron Fission

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.

Mass yield curves in low-energy proton-induced fission ofU233,U235,U236,Np237,Pu239,Pu242,Pu244,Am241, andAm243

1991 ◽  
Vol 44 (4) ◽  
pp. 1405-1423 ◽  
Author(s):  
T. Ohtsuki ◽  
Y. Nagame ◽  
K. Tsukada ◽  
N. Shinohara ◽  
S. Baba ◽  
...  
Keyword(s):  
Low Energy ◽  
Mass Yield ◽  
Yield Curves ◽  
Energy Proton ◽  
Induced Fission

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

1978 ◽  
Vol 56 (10) ◽  
pp. 1340-1352 ◽  
Author(s):  
Masako Shima ◽  
H. G. Thode ◽  
R. H. Tomlinson
Keyword(s):  
Thermal Neutron ◽  
Isotope Dilution ◽  
Yield Curve ◽  
Mass Region ◽  
Mass Yield ◽  
Neutron Fission ◽  
Significant Depression ◽  
Thermal Neutron Fission ◽  
Induced Fission ◽  
Fission Yields

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.

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.

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.

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.

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