Development of a Physics-Based Toolset for Simulating ESD Events Full set of Maxwell’s equations + Plasma kinetic model incorporating all relevant physics + COMSOL implementation (modules)+ Experimental validation (sufficiently conservative)
Conference
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OSTI ID:1417154
- Los Alamos National Laboratory
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC52-06NA25396
- OSTI ID:
- 1417154
- Report Number(s):
- LA-UR-18-20240
- Resource Relation:
- Conference: Tri-Lab Dialogue on Weapon Response ; 2017-12-04 - 2017-12-08 ; Albuquerque, New Mexico, United States
- Country of Publication:
- United States
- Language:
- English
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Most theoretical approaches used in nuclear astrophysics to model the nucleosynthesis of heavy elements incorporate the so-called statistical model in order to describe the excitation and decay properties of atomic nuclei. One of the basic assumptions of this model is the validity of the Brink–Axel hypothesis and the related concept of so-called photon strength functions to describe γ-ray transition probabilities. We present a novel experimental approach that allows for the first time to experimentally determine the photon strength function simultaneously in two independent ways by a unique combination of quasi-monochromatic photon beams and a newly implemented γ–γ coincidence setup. This technique does not assume a priori the validity of the Brink–Axel hypothesis and sets a benchmark in terms of the detection sensitivity for measuring decay properties of photo-excited states below the neutron separation energy. The data for the spherical off-shell nucleus 128Te were obtained for γ-ray beam-energy settings between 3 MeV and 9 MeV in steps of 130 keV for the lower beam energies and in steps of up to 280 keV for the highest beam settings. We present a quantitative analysis on the consistency of the derived photon strength function with the Brink–Axel hypothesis. The data clearly demonstrate a discrepancy of up to a factor of two between the photon strength functions extracted from the photoabsorption and photon emission process, respectively. In addition, we observe that the photon strength functions are not independent of the excitation energy, as usually assumed. Thus, we conclude, that the Brink–Axel hypothesis is not strictly fulfilled in the excitation-energy region below the neutron separation threshold (Sn = 8.78 MeV) for the studied case of 128Te.
Multirate Particle-in-Cell Time Integration Techniques of Vlasov-Maxwell Equations for Collisionless Kinetic Plasma Simulations
Computational ESD Study: Physics- Based Simulations
Journal Article
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Tue Jan 01 00:00:00 EST 2019
· Physics Letters B
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OSTI ID:1417154
+10 more
Multirate Particle-in-Cell Time Integration Techniques of Vlasov-Maxwell Equations for Collisionless Kinetic Plasma Simulations
Conference
·
Fri Jul 31 00:00:00 EDT 2015
·
OSTI ID:1417154
+1 more
Computational ESD Study: Physics- Based Simulations
Conference
·
Tue Sep 19 00:00:00 EDT 2017
·
OSTI ID:1417154