Angular distributions of fragments originating from the spontaneous fission of oriented nuclei and problem of the conservation of the spin projection onto the symmetry axis of a fissile nucleus

2005 ◽  
Vol 68 (9) ◽  
pp. 1433-1442 ◽  
Author(s):  
S. G. Kadmensky ◽  
L. V. Rodionova
Keyword(s):  
Spontaneous Fission ◽  
Symmetry Axis ◽  
Angular Distributions ◽  
Spin Projection ◽  
Fissile Nucleus

scholarly journals 238U FISSION NEAR THE THRESHOLD

2020 ◽  
pp. 23-26
Author(s):  
V.M. Khvastunov ◽  
V.I. Kasilov ◽  
S.S. Kochetov ◽  
A.A. Khomich
Keyword(s):  
Angular Distribution ◽  
Cross Section ◽  
Symmetry Axis ◽  
Fission Cross Section ◽  
Spin Projection ◽  
Quadrupole Excitation ◽  
Fission Fragments

Using the data on angular distribution of fission fragments, a threshold has been determined in a dipole fission channel with J = 1 spin projection to the nucleus symmetry axis. It has been shown that the peak observed in the 238U fission cross section is determined by the contribution from the quadrupole excitation.

scholarly journals Prompt fission gamma rays and their angular distributions

2018 ◽  
Vol 193 ◽  
pp. 03005
Author(s):  
Andreas Oberstedt ◽  
Robert Billnert ◽  
Angélique Gatera ◽  
Alf Göök ◽  
Stephan Oberstedt
Keyword(s):  
Gamma Rays ◽  
Spontaneous Fission ◽  
Neutron Emission ◽  
Early Stage ◽  
Angular Distributions ◽  
Recent Measurement ◽  
Excitation Process ◽  
Angular Correlations ◽  
Γ Rays ◽  
Prompt Fission

In a recent measurement of prompt γ rays from the spontaneous fission of 252Cf an experimental setup was chosen that allowed the study of angular correlations between γ rays and the nuclei from which they were emitted. The observed angular distribution of the prompt fission γ rays was then analyzed to estimate the relative contributions from radiation of different multipolarity. From that we hope to obtain more detailed information about the early stage of the de-excitation process of fission fragments, right after prompt neutron emission. First preliminary results are presented below.

scholarly journals Prompt gamma rays from 252Cf(sf) and their angular distributions

2018 ◽  
Vol 169 ◽  
pp. 00014
Author(s):  
Andreas Oberstedt ◽  
Robert Billnert ◽  
Angélique Gatera ◽  
Alf Göök ◽  
Stephan Oberstedt
Keyword(s):  
Monte Carlo ◽  
Gamma Rays ◽  
Spontaneous Fission ◽  
Angular Distributions ◽  
Recent Measurement ◽  
Prompt Gamma ◽  
Experimental Setup ◽  
Angular Correlations ◽  
Γ Rays ◽  
Prompt Fission

In a recent measurement of prompt γ rays from the spontaneous fission of 252Cf an experimental setup was chosen that allowed the study of angular correlations between γ rays and the nuclei from which they were emitted. The observed angular distribution of prompt fission γ rays was then analyzed to estimate the relative contributions from radiation of different multipolarity. First preliminary results are presented and compared to previous angular correlation measurements from different fission processes and recent results from calculations with the Monte Carlo Hauser-Feshbach code FIFRELIN.

Velocity and Angular Distributions of Prompt Neutrons from Spontaneous Fission ofCf252

1962 ◽  
Vol 126 (6) ◽  
pp. 2120-2136 ◽  
Author(s):  
Harry R. Bowman ◽  
Stanley G. Thompson ◽  
J. C. D. Milton ◽  
Wladyslaw J. Swiatecki
Keyword(s):  
Spontaneous Fission ◽  
Angular Distributions

scholarly journals A double-Bragg detector with digital signal processing for the event-by-event study of fission in actinide nuclei

2016 ◽  
Vol 44 ◽  
pp. 1660231
Author(s):  
R. J. W. Frost ◽  
A. G. Smith
Keyword(s):  
Signal Processing ◽  
Spontaneous Fission ◽  
Polar Angle ◽  
Digital Signal ◽  
Angular Distributions ◽  
Electron Collection ◽  
Signal Correction ◽  
Anode Signal ◽  
A Charge ◽  
Collection Time

In the current paper, a windowless double-Bragg chamber incorporating full signal digitisation has been developed for the purpose of studying the energy (E), mass (A), charge (Z) and angular distributions ([Formula: see text], [Formula: see text] of nuclei generated by fission. This device measures E for each fission fragment by collection of the charge produced during ionisation of the fill gas. Subsequent digitisation of the signals from each of two anodes yields information on dE/dx, as well as electron collection time, which can be further used for polar angle ([Formula: see text] determination. Frisch-grid and cathode signals are also digitised and are used both for anode signal correction and to produce further information on [Formula: see text]. To verify the operation of this detector, three angular determination techniques from the literature were implemented, and the results were found to be consistent with the referenced paper. Current results from the spontaneous fission of [Formula: see text]Cf are presented.

Assessing the Calculation of Exchange Coupling Constants and Spin Crossover Gaps Using the Approximate Projection Model to Improve Density Function Calculations

2019 ◽  
Author(s):  
Xianghai Sheng ◽  
Lee Thompson ◽  
Hrant Hratchian
Keyword(s):  
Density Functional Theory ◽  
Exchange Coupling ◽  
Density Functional ◽  
Spin Crossover ◽  
Coupling Constants ◽  
Spin Projection ◽  
Coupling Constant ◽  
Projection Model ◽  
Functional Theory

This work evaluates the quality of exchange coupling constant and spin crossover gap calculations using density functional theory corrected by the Approximate Projection model. Results show that improvements using the Approximate Projection model range from modest to significant. This study demonstrates that, at least for the class of systems examined here, spin-projection generally improves the quality of density functional theory calculations of J-coupling constants and spin crossover gaps. Furthermore, it is shown that spin-projection can be important for both geometry optimization and energy evaluations. The Approximate Project model provides an affordable and practical approach for effectively correcting spin-contamination errors in molecular exchange coupling constant and spin crossover gap calculations.

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