THE RELATIVE YIELDS OF THE ISOTOPES OF XENON IN PLUTONIUM FISSION

1956 ◽  
Vol 34 (3) ◽  
pp. 193-200 ◽  
Author(s):  
W. H. Fleming ◽  
H. G. Thode
Keyword(s):  
Fine Structure ◽  
Mass Range ◽  
Mass Chain ◽  
Fission Yields

The relative fission yields of five isotopes of xenon in Pu239 fission have been determined. Fine structure, similar to that observed in U238 fission but smaller, occurs in plutonium fission in the xenon mass range. The yield of the 133 mass chain has been determined at xenon in order to permit the normalization of the relative xenon yields to the relative cesium yields.

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.

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.

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 Measurement of fission yields and isomeric yield ratios at IGISOL

2018 ◽  
Vol 169 ◽  
pp. 00017
Author(s):  
Stephan Pomp ◽  
Andrea Mattera ◽  
Vasileios Rakopoulos ◽  
Ali Al-Adili ◽  
Mattias Lantz ◽  
...  
Keyword(s):  
Penning Trap ◽  
Mass Range ◽  
Experimental Program ◽  
Fission Yield ◽  
Yield Data ◽  
Fission Process ◽  
Isomeric Yield ◽  
First Results ◽  
Igisol Facility ◽  
Fission Yields

Data on fission yields and isomeric yield ratios (IYR) are tools to study the fission process, in particular the generation of angular momentum. We use the IGISOL facility with the Penning trap JYFLTRAP in Jyväskylä, Finland, for such measurements on 232Th and natU targets. Previously published fission yield data from IGISOL concern the 232Th(p,f) and 238U(p,f) reactions at 25 and 50 MeV. Recently, a neutron source, using the Be(p,n) reaction, has been developed, installed and tested. We summarize the results for (p,f) focusing on the first measurement of IYR by direct ion counting. We also present first results for IYR and relative yields for Sn and Sb isotopes in the 128-133 mass range from natU(n,f) based on γ-spectrometry. We find a staggering behaviour in the cumulative yields for Sn and a shift in the independent fission yields for Sb as compared to current evaluations. Plans for the future experimental program on fission yields and IYR measurements are discussed.

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.

Cumulative Yields of the Heavy Fragments in the Fast Neutron Fission of 238U

1972 ◽  
Vol 50 (24) ◽  
pp. 3100-3110 ◽  
Author(s):  
C. K. Mathews ◽  
R. H. Tomlinson
Keyword(s):  
Isotope Dilution ◽  
Mass Range ◽  
Mass Region ◽  
Mass Spectrometric ◽  
Spectrometric Method ◽  
Mass Spectrometric Method ◽  
Neutron Fission ◽  
Fission Spectrum ◽  
Isotopic Abundances ◽  
Fission Yields

Isotopic abundances of the elements xenon, cesium, barium, cerium, neodymium, and samarium formed in the fast (fission spectrum) neutron fission of 238U have been measured using the mass spectrometric method. These ratios were normalized with respect to each other through isobaric nuclides and isotope dilution to obtain the relative yields of isobaric chains in the heavy mass region. By normalizing the heavy mass yields to 100%, the absolute fission yields of 20 chains in the 130–154 mass range were determined.

The fine structure of the fission yields of heavy nuclei

1977 ◽  
Vol 42 (4) ◽  
pp. 379-380
Author(s):  
K. A. Pietrzak ◽  
E. V. Platygina ◽  
V. F. Teplykh
Keyword(s):  
Fine Structure ◽  
Heavy Nuclei ◽  
Fission Yields

Fine structure in the region of symmetric mass distribution for cumulative fission yields

1969 ◽  
Vol 47 (3) ◽  
pp. 275-278 ◽  
Author(s):  
K. S. Thind ◽  
R. H. Tomlinson
Keyword(s):  
Fine Structure ◽  
Yield Curve ◽  
Neutron Emission ◽  
Central Peak ◽  
Mass Region ◽  
Mass Yield ◽  
Neutron Fission ◽  
Energy Neutron ◽  
Cumulative Mass ◽  
Fission Yields

It is predicted that there should be fine structure in the cumulative mass yield curve in the symmetric mass region where major discontinuities in the neutron emission vs. mass curve exist. In the case of low-energy neutron fission of 238U, this fine structure takes the form of a pronounced depression in the region of mass 125. Under similar conditions for 232Th, the fine structure may take the form of depressions in the region of mass 110 and 125 so that the cumulative mass yield curve appears to have a central peak.

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