Fission of Ag and Br nuclei in 20 GeV/c proton interactions

1968 ◽  
Vol 46 (20) ◽  
pp. 2301-2307
Author(s):  
G. C. Deka ◽  
K. C. Deka
Keyword(s):  
Nuclear Emulsion ◽  
Nuclear Fission ◽  
Binary Fission ◽  
Fission Fragments ◽  
Space Angle ◽  
The Mean

In the analysis of a sample of 1424 stars produced in nuclear emulsion by 20 GeV/c protons, 107 stars are found to contain short dense tracks, which have been interpreted as due to nuclear fission. The mean range and velocity of the fission fragments are estimated to be ~9.9 μ and ~0.047 c respectively, compared with ~4.8 μ and ~0.026 c respectively for the residual recoils of ordinary stars. The average space angle between the products of binary fission is found to be 128°.

BINARY AND TERNARY FISSION WITHIN THE STATISTICAL MODEL

2008 ◽  
Vol 17 (10) ◽  
pp. 2014-2019 ◽  
Author(s):  
GURGEN G. ADAMIAN ◽  
ALEXANDER V. ANDREEV ◽  
NIKOLAI V. ANTONENKO ◽  
WERNER SCHEID
Keyword(s):  
Statistical Model ◽  
Nuclear Fission ◽  
Binary Fission ◽  
Ternary Fission ◽  
Scission Point ◽  
Fission Fragments ◽  
Charge Distributions

The binary and ternary nuclear fission are treated within the statistical model. At the scission point we calculate the potentials as functions of the deformations of the fragments in the dinuclear model. The potentials give the mass and charge distributions of the fission fragments. The ternary fission is assumed to occur during the binary fission.

scholarly journals Impact of nuclear inertia momenta on fission observables

2018 ◽  
Vol 193 ◽  
pp. 01004
Author(s):  
P. Tamagno ◽  
O. Litaize
Keyword(s):  
Rigid Body ◽  
Excitation Energy ◽  
Nuclear Fission ◽  
Particle Model ◽  
Rotational Inertia ◽  
Neutron Fission ◽  
Fission Fragments ◽  
Rigid Body Model ◽  
Two Parameters ◽  
The Impact

Fission is probably the nuclear process the less accurately described with current models because it involves dynamics of nuclear matter with strongly coupled manybody interactions. It is thus diffcult to find models that are strongly rooted in good physics, accurate enough to reproduce target observables and that can describe many of the nuclear fission observables in a consistent way. One of the most comprehensive current modeling of the fission process relies on the fission sampling and Monte-Carlo de-excitation of the fission fragments. This model is implemented for instance in the FIFRELIN code. In this model fission fragments and their state are first sampled from pre-neutron fission yields, angular momentum distribution and excitation energy repartition law then the decay of both initial fragments is simulated. This modeling provides many observables: prompt neutron and gamma fission spectra, multiplicities and also fine decompositions: number of neutrons emitted as a function of the fragment mass, spectra per fragments, etc. This model relies on nuclear structure databases and on several basic nuclear models describing for instance gamma strength functions or level densities. Additionally some free parameters are still to be determined, namely two parameters describing the excitation energy repartition law, the spin cutoff of the heavy and light fragments and a rescaling parameter for the rotational inertia momentum of the fragments with respect of the rigid-body model. In the present work we investigate the impact of this latter parameter. For this we mainly substitute the corrected rigid-body value by a quantity obtained from a microscopic description of the fission fragment. The independent-particle model recently implemented in the CONRAD code is used to provide nucleonic wave functions that are required to compute inertia momenta with an Inglis-Belyaev cranking model. The impact of this substitution is analyzed on different fission observables provided by the FIFRELIN code.

scholarly journals The 4-dimensional Langevin approach to low energy nuclear fission

2018 ◽  
Vol 169 ◽  
pp. 00005
Author(s):  
F.A. Ivanyuk ◽  
C. Ishizuka ◽  
M.D. Usang ◽  
S. Chiba
Keyword(s):  
Excitation Energy ◽  
Mass Number ◽  
Nuclear Fission ◽  
Deformation Energy ◽  
Low Energy ◽  
Tooth Structure ◽  
Fission Fragments ◽  
Langevin Approach ◽  
Intrinsic Excitation ◽  
Mother Nucleus

We applied the four-dimensional Langevin approach to the description of fission of 235U by neutrons and calculated the dependence of the excitation energy of fission fragments on their mass number. For this we have fitted the compact just-before-scission configuration obtained by the Langevin calculations by the two separated fragments and calculated the intrinsic excitation and the deformation energy of each fragment accurately taking into account the shell and pairing effects and their dependence on the temperature and mass of the fragments. For the sharing of energy between the fission fragments we have used the simplest and most reliable assumption - the temperature of each fragment immediately after the neck rupture is the same as the temperature of mother nucleus just before scission. The calculated excitation energy of fission fragments clearly demonstrates the saw-tooth structure in the dependence on fragment mass number.

ELISe: A NEW FACILITY FOR UNPRECEDENTED EXPERIMENTAL NUCLEAR FISSION STUDIES

2009 ◽  
Vol 18 (04) ◽  
pp. 767-772 ◽  
Author(s):  
J. TAIEB ◽  
G. BELIER ◽  
A. CHATILLON ◽  
T. GRANIER ◽  
A. KELIC ◽  
...  
Keyword(s):  
Inverse Kinematics ◽  
Total Mass ◽  
Nuclear Fission ◽  
Experimental Program ◽  
Fission Process ◽  
Fission Fragments ◽  
Charge Resolution ◽  
New Facility

A novel experimental program aiming to study the properties of fragments and neutrons emitted in the fission process has been initiated. The experiment will be held at the ELISe electron-ion collider to be constructed at GSI, Darmstadt in the framework of the FAIR extension of the facility. The experiment will take advantage of the inverse kinematics allowing, in particular, a total mass and charge resolution for all fission fragments.

scholarly journals Fission fragments observables measured at the LOHENGRIN spectrometer

2020 ◽  
Vol 239 ◽  
pp. 05017
Author(s):  
S. Julien-Laferrière ◽  
L. Thombansen ◽  
G. Kessedjian ◽  
A. Chebboubi ◽  
O. Serot ◽  
...  
Keyword(s):  
Neutron Emission ◽  
Evaluation Process ◽  
Nuclear Data ◽  
Nuclear Fission ◽  
Experimental Program ◽  
Spent Fuel ◽  
Ionic Charge ◽  
Fission Fragments ◽  
Common Effort ◽  
Fission Yields

Nuclear fission yields are key data for reactor studies, such as spent fuel inventory or decay heat, and for understanding fission process. Despite a significant effort allocated to measure fission yields during the last decades, the recent evaluated libraries still need improvements in particular in the reduction of the uncertainties. Moreover, some discrepancies between these libraries must be explained. Additional measurements provide complementary information and estimations of experimental correlations, and new kinds of measurements enable to test the models used during the nuclear data evaluation process. A common effort by the CEA, the LPSC and the ILL aims at tackling these issues by providing precise measurements of isotopic and isobaric fission yields with the related variance-covariance matrices. Additionally, the experimental program involves a large range of observables requested by the evaluations, such as kinetic energy dependency of isotopic yields and odd-even effect in order to test the sharing of total excitation energy and the spin generation mechanism. Another example is the complete range of isotopic distribution per mass that allows the determination of the charge polarization, which has to be consistent for complementary masses (pre-neutron emission). For instance, this information is the key observable for the evaluation of isotopic yields. Finally, ionic charge distributions are indirect measurements of nanosecond isomeric ratios as a probe of the nuclear de-excitation path in the (E*, J, π) representation. Measurements for thermal neutron induced fission of 241 Pu have been carried out at the ILL in Grenoble, using the LOHENGRIN mass spectrometer. Methods, results and comparison to models calculations will be presented corresponding to a status on fission fragments observables reachable with this facility.

scholarly journals Attempts to detect the emission of secondary charged particles in the fission of 235 U by slow neutrons

1947 ◽  
Vol 191 (1027) ◽  
pp. 428-441 ◽  
Keyword(s):  
Thin Film ◽  
Charged Particle ◽  
Uranium Oxide ◽  
Charged Particles ◽  
The Other ◽  
Light Charged Particle ◽  
Fission Fragments ◽  
The Mean ◽  
Light Charged Particles ◽  
Α Particles

If light charged particles (protons, α-particles, etc.) are emitted during fission, it should be possible to establish this fact by a simple coincidence experiment. Suppose two detectors are arranged so that they can both ‘see’ a thin film of uranium oxide. Let one of the detectors register the entry of fission fragments only, say at the rate of F (sec. -1 ). Let the other detector register not only fission fragments (unless they are excluded by an interposed absorber) but also light charged particles (protons, a-particles, etc.) with energies within certain limits. Suppose that the rate of registration in the second detector is P (sec. -1 ), that the mean efficiency for the detection of a light charged particle emitted from the uranium film is e , and that the average number of light charged particles liberated per fission is η.

scholarly journals Preheating of heavy-ion-beam targets by secondary particles

1992 ◽  
Vol 10 (1) ◽  
pp. 189-200 ◽  
Author(s):  
M. M. Basko
Keyword(s):  
Ion Beam ◽  
Nuclear Fission ◽  
Heavy Ion ◽  
Ion Beams ◽  
X Ray ◽  
Fission Fragments ◽  
Secondary Particles ◽  
The Face ◽  
Heavy Ion Beam

The contribution of different sorts of secondary particles to the preheating of thermonuclear targets driven by heavy-ion beams is analyzed. Two types of illumination geometry are considered: side-on and face-on locations of the fuel with respect to the ion beam. It is shown that a substantial preheating can be expected from (1) nuclear fission fragments for the face-on fuel position and (2) δ-electrons and low-Z nuclear fragments for the side-on fuel location. All the X-ray and gamma photons of various origin are shown to produce a negligible fuel heating.

Distributions of the Initial Fragment Kinetic Energy in Binary and Ternary Fission

1971 ◽  
Vol 49 (22) ◽  
pp. 2778-2784 ◽  
Author(s):  
P. B. Vitta
Keyword(s):  
Kinetic Energy ◽  
Translational Motion ◽  
Nuclear Fission ◽  
Binary Fission ◽  
Energy Spectra ◽  
Initial Kinetic Energy ◽  
Ternary Fission ◽  
Internal Excitation ◽  
Initial Excitation ◽  
Fragment Kinetic Energy

The statistical theory of nuclear fission was originally developed to deal with binary fission. An attempt is made to extend the theory to the case of ternary fission. The probability of a fission mode, given that the nucleus divides into three fragments, is first calculated. Attention is thereafter focused only on the probability distribution of fission modes representing the various possible allocations to the fragment translational motion and internal excitation of the energy available for both translation and excitation. This leads to ternary-fission distributions of the initial kinetic energy (and to complementary distributions of the initial excitation energy) of the fissioning nucleus. Our results show that the ternary-fission distributions of the initial kinetic energy are wider with peaks at higher values of kinetic energy than the corresponding binary-fission distributions obtained previously. The (spontaneous-) ternary-fission distributions are peaked at energies of the order of 1 MeV and have full-widths-at-half-maximum (FWHM) in the neighborhood of 3 MeV. These figures are of experimental interest, since they may be used to predict the energy spectra of the fission fragments in ternary fission.

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