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

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 Modeling of fine structures in the mass distribution of nuclear reaction products and their recognition by machine learning methods

2020 ◽  
pp. 20-29
Author(s):  
Gennady Ososkov ◽  
Yuriy Pyatkov ◽  
Mikhail Rudenko
Keyword(s):  
Machine Learning ◽  
Fine Structure ◽  
Computer Model ◽  
Transuranium Element ◽  
Heavy Nuclei ◽  
Binary Classifier ◽  
Reaction Products ◽  
Machine Learning Methods ◽  
Fine Structures ◽  
Deep Convolution Network

The article is devoted to the analysis of manifestations in rare multibody decays of heavy nuclei. Together with physicists from the FLNR JINR, a computer model of the fine structure was developed, which they found on the basis of experiments on with transuranium element Californium. To test the hypothesis that the structure found is a meaningful, and is not a noise artifact, it was proposed to use a deep convolution network as a binary classifier trained on a large sample of model and noise images. Preliminary results of using the developed neuroclassifier show prospects of the proposed approach.

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.

Fine structure ofαdecay to rotational states of heavy nuclei

2010 ◽  
Vol 81 (6) ◽  
Author(s):  
Y. Z. Wang ◽  
J. M. Dong ◽  
B. B. Peng ◽  
H. F. Zhang
Keyword(s):  
Fine Structure ◽  
Heavy Nuclei ◽  
Rotational States

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.

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 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.

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