scholarly journals Muon-induced fission in 235U and 238U

1986 ◽  
Vol 64 (6) ◽  
pp. 665-670 ◽  
Author(s):  
S. Ahmad ◽  
O. Häusser ◽  
J. A. Macdonald ◽  
B. H. Olaniyi ◽  
A. Olin ◽  
...  
Keyword(s):  
Muon Capture ◽  
Neutron Decay ◽  
X Rays ◽  
Disappearance Rate ◽  
Decay Modes ◽  
Fission Fragments ◽  
Short Lifetime ◽  
Induced Fission ◽  
Prompt Fission ◽  
Fission Yields

Muon-induced prompt and delayed fission yields in 235U and 238U have been measured. A coincidence with the muonic uranium Kα X-rays was used to identify the muon stop in the target. The experimental absolute fission yields per muon stop were 0.142 ± 0.023 for 235U and 0.068 ± 0.013 for 238U. The disappearance rate of muons from the 1s state of muonic uranium has also been measured in the fission mode. Muon-induced fission lifetimes were 71.6 ± 0.6 ns for 235U and 77.2 ± 0.4 ns for 238U. No evidence for a short-lifetime fission – isomer component was found. Comparison of lifetime results with previously measured values in the electron, gamma, and neutron decay modes indicated that the systematic discrepancies could be explained by muon capture on fission fragments produced from prompt fission.

INDEPENDENT YIELDS OF 124Sb AND 126sb IN THERMAL NEUTRON INDUCED FISSION AND THEIR IMPLICATION ON THE EMPIRICAL Zp FUNCTION

1965 ◽  
Vol 43 (9) ◽  
pp. 2493-2507 ◽  
Author(s):  
P. O. Strom ◽  
G. R. Grant ◽  
A. C. Pappas
Keyword(s):  
Thermal Neutron ◽  
Charge Distribution ◽  
Distribution Curve ◽  
Neutron Emission ◽  
Shell Effect ◽  
Shell Effects ◽  
Fission Fragments ◽  
Induced Fission ◽  
Fission Yields ◽  
Proton Shell

The independent fission yields in thermal neutron induced fission of 235U have been measured to be (9.5 ± 1.4)•10−6% and (1.04 ± 0.17)•10−3% for 124gSb and 126gSb, respectively. The total independent yields for all isomers of these nuclides are estimated to be (1.2 ± 0.2)•10−5% for 124Sb and (3.7 ± 0.6)•10−3% for 126Sb using a Huizenga–Vandenbosch approach for estimating population of isomeric states.These data do not seem to support a 50 proton shell effect on the Zp function, using the "unique" charge distribution curve of Wahl. A revised Wahl plot based on recent information on neutron emission from individual fission fragments is given and discussed in view of shell effects in fission. It is shown that the effect of the Zp function of the 50 proton shell is very small.

scholarly journals Fission studies at IGISOL/JYFLTRAP: Simulations of the ion guide for neutron-induced fission and comparison with experimental data

2020 ◽  
Vol 239 ◽  
pp. 17019
Author(s):  
Z. Gao ◽  
A. Solders ◽  
A. Al-Adili ◽  
L. Canete ◽  
T. Eronen ◽  
...  
Keyword(s):  
Extraction Efficiency ◽  
Fission Products ◽  
Recent Measurement ◽  
Buffer Gas ◽  
Fission Yield ◽  
Fission Fragments ◽  
Ion Guide ◽  
Igisol Facility ◽  
Induced Fission ◽  
Fission Yields

For the production of exotic nuclei at the IGISOL facility, an ion guide for neutron-induced fission has been developed and tested in experiments. Fission fragments are produced inside the ion guide and collected using a helium buffer gas. Meanwhile, a GEANT4 model has been developed to simulate the transportation and stopping of the charged fission products. In a recent measurement of neutron-induced fission yields, implantation foils were located at different positions in the ion guide. The gamma spectra from these foils and the fission targets are compared to the results from the GEANT4 simulation. In order to allow fission yield measurements in the low yield regions, towards the tails and in the symmetric part of the mass distribution, the stopping and extraction efficiency of the ion guide has to be significantly improved. This objective can be achieved by increasing the size while introducing electric field guidance using a combination of static electrodes and an RF-carpet. To this end, the GEANT4 model is used to optimise the design of such an ion guide.

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.

Times of emission of K x rays from U235 fission fragments of known mass

1974 ◽  
Vol 45 (5) ◽  
pp. 2327-2335 ◽  
Author(s):  
R. A. Lerche ◽  
B. W. Wehring ◽  
M. E. Wyman
Keyword(s):  
X Rays ◽  
Fission Fragments ◽  
U235 Fission

scholarly journals Angular distributions and anisotropy of fission fragments from neutron-induced fission in intermediate energy range 1–200 MeV

2017 ◽  
Vol 146 ◽  
pp. 04011 ◽  
Author(s):  
Alexander S. Vorobyev ◽  
Alexei M. Gagarski ◽  
Oleg A. Shcherbakov ◽  
Larisa A. Vaishnene ◽  
Alexei L. Barabanov
Keyword(s):  
Energy Range ◽  
Intermediate Energy ◽  
Angular Distributions ◽  
Fission Fragments ◽  
Induced Fission

Angular Distribution of Fission Fragments from 22-Mev Proton-Induced Fission ofU238,U235,U233,Th232, andTh230

1955 ◽  
Vol 98 (3) ◽  
pp. 685-687 ◽  
Author(s):  
B. L. Cohen ◽  
B. L. Ferrell-Bryan ◽  
D. J. Coombe ◽  
M. K. Hullings
Keyword(s):  
Angular Distribution ◽  
Fission Fragments ◽  
Induced Fission

scholarly journals Influence of spin on fission fragments anisotropy

2005 ◽  
Vol 20 (1) ◽  
pp. 45-49
Author(s):  
Omid Ghodsi ◽  
Aziz Behkami ◽  
Farhad Rahimi
Keyword(s):  
Experimental Data ◽  
Level Density ◽  
Couple Channel ◽  
Spin Effect ◽  
Nuclear Level Density ◽  
Nuclear Level ◽  
Fission Fragments ◽  
Fragment Angular Distribution ◽  
Induced Fission ◽  
Channel Spin

An analysis of selected fission fragment angular distribution when at least one of the spins of the projectile or target is appreciable in induced fission was made by using the statistical scission model. The results of this model predicate that the spins of the projectile or target are affected on the nuclear level density of the compound nucleus. The experimental data was analyzed by means of the couple channel spin effect formalism. This formalism suggests that the projectile spin is more effective on angular anisotropies within the limits of energy near the fusion barrier.

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