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M Tardocchi - One of the best experts on this subject based on the ideXlab platform.
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calculated Neutron Emission spectrum with knock on effects for rf heated 3he d plasmas
Nuclear Fusion, 2011Co-Authors: G Gorini, M. Nocente, J Kallne, M TardocchiAbstract:The Neutron Emission from (3He)D plasmas with RF heating is calculated using a model that includes supra-thermal (knock-on) components of the deuteron population. The RF generation of fast 3He ions is described and the knock-on components were determined with the help of newly derived 3He + d scattering cross sections. Results are presented on the Neutron Emission spectrum and its contributions from different deuteron velocity components. It is shown that knock-on leaves an observable feature in the spectrum with a clear dependence on absorbed RF power. The importance of the nuclear interaction in the elastic cross section is demonstrated. The results represent a step forward in the use of Neutron Emission spectroscopy to diagnose fusion plasmas with minority supra-thermal components in their fuel ion composition.
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Neutron Emission levels during the ITER zero-activation phase
Nuclear Fusion, 2010Co-Authors: M. Gatu Johnson, Sean Conroy, C Hellesen, E Ronchi, G Gorini, Göran Ericsson, M. Nocente, E. Andersson Sundén, Marco Cecconello, M TardocchiAbstract:In recent experiments at JET, a contribution to the Neutron Emission from reactions between beryllium and 3He, 4He and H has been identified. With the beryllium walled planned for ITER, this raises ...
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Neutron Emission generated by fast deuterons accelerated with ion cyclotron heating at jet
Nuclear Fusion, 2010Co-Authors: C Hellesen, Gatu M Johnson, Anderson E Sunden, S Conroy, G Ericsson, E Ronchi, Henrik Sjostrand, M Weiszflog, G Gorini, M TardocchiAbstract:For the first time, the Neutron Emission from JET plasmas heated with combined deuterium neutral beam injection and third harmonic ion cyclotron radio frequency heating have been studied with Neutron Emission spectroscopy (NES). Very high DD Neutron rates were observed with only modest external heating powers, which was attributed to acceleration of deuterium beam ions to energies of about 2-3 MeV, where the DD reactivity is on a par of that of the DT reaction. Fast deuterium energy distributions were derived from analysis of NES data and confirm acceleration of deuterium beam ions up to energies around 3 MeV, in agreement with theoretical predictions. The high Neutron rates allowed for observations of changes in the fast deuterium populations on a time scale of 50 ms. Correlations were seen between fast deuterium ions at different energies and magnetohydrodynamic activities, such as monster sawtooth crashes and toroidal Alfven eigenmodes.
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Ion temperature and plasma rotation profile effects in the Neutron Emission spectrum
Review of Scientific Instruments, 2004Co-Authors: M Tardocchi, G Gorini, H. Henriksson, Jan KällneAbstract:The instrumental factors and measuring conditions affecting Neutron Emission spectrometry measurements of tokamak plasmas are described and analyzed. The measured energy broadening and shift of the Neutron Emission is used to deduce ion temperature (Ti) and toroidal plasma rotation velocity (Vt) representing average (effective) values for the nonuniform plasma volume viewed. Analytical expressions are derived for the relationship between the line-volume integrated effective temperature (Teff) and the radial profile Ti(r) for the case of thermal plasmas with isotropic Neutron Emission; effects on Teff due to spectral broadening from the radial dependence Vt(r) were also considered. The analysis method presented here is applied to high quality data obtained with the magnetic proton recoil Neutron spectrometer installed at Joint European Torus for measurements of deuterium–tritium plasmas. Similarly, cases of anisotropic Neutron Emission were quantitatively assessed.
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Neutron Emission spectroscopy of radio frequency heated (D)T plasmas
Nuclear Fusion, 2002Co-Authors: M Tardocchi, Sean Conroy, G Gorini, H. Henriksson, Göran Ericsson, Jan KällneAbstract:The energy spectrum of the d+t→α+n Neutron Emission has been measured in experiments carried out at JET for plasmas of deuterium–tritium subjected to minority ion cyclotron resonance heating (ICRH) tuned to deuterium. The data obtained with the magnetic proton recoil spectrometer were of sufficient quality to distinguish up to three spectral components of Neutron Emission some of which were time resolved. A new analysis model was used to derive information on the underlying deuteron velocity distributions and their corresponding energy densities in the plasma. This experiment represents the first use of Neutron Emission spectroscopy for detailed diagnosis of the response of fusion plasmas to the applied ICRH power for different plasma conditions, including the time evolution over the heating pulse duration for individual discharges. In particular, ICRH effects on the plasma, together with the power absorption mechanisms, were studied as a function of the minority ion concentration in the range 9–20%.
G Gorini - One of the best experts on this subject based on the ideXlab platform.
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calculated Neutron Emission spectrum with knock on effects for rf heated 3he d plasmas
Nuclear Fusion, 2011Co-Authors: G Gorini, M. Nocente, J Kallne, M TardocchiAbstract:The Neutron Emission from (3He)D plasmas with RF heating is calculated using a model that includes supra-thermal (knock-on) components of the deuteron population. The RF generation of fast 3He ions is described and the knock-on components were determined with the help of newly derived 3He + d scattering cross sections. Results are presented on the Neutron Emission spectrum and its contributions from different deuteron velocity components. It is shown that knock-on leaves an observable feature in the spectrum with a clear dependence on absorbed RF power. The importance of the nuclear interaction in the elastic cross section is demonstrated. The results represent a step forward in the use of Neutron Emission spectroscopy to diagnose fusion plasmas with minority supra-thermal components in their fuel ion composition.
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Neutron Emission levels during the ITER zero-activation phase
Nuclear Fusion, 2010Co-Authors: M. Gatu Johnson, Sean Conroy, C Hellesen, E Ronchi, G Gorini, Göran Ericsson, M. Nocente, E. Andersson Sundén, Marco Cecconello, M TardocchiAbstract:In recent experiments at JET, a contribution to the Neutron Emission from reactions between beryllium and 3He, 4He and H has been identified. With the beryllium walled planned for ITER, this raises ...
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Neutron Emission generated by fast deuterons accelerated with ion cyclotron heating at jet
Nuclear Fusion, 2010Co-Authors: C Hellesen, Gatu M Johnson, Anderson E Sunden, S Conroy, G Ericsson, E Ronchi, Henrik Sjostrand, M Weiszflog, G Gorini, M TardocchiAbstract:For the first time, the Neutron Emission from JET plasmas heated with combined deuterium neutral beam injection and third harmonic ion cyclotron radio frequency heating have been studied with Neutron Emission spectroscopy (NES). Very high DD Neutron rates were observed with only modest external heating powers, which was attributed to acceleration of deuterium beam ions to energies of about 2-3 MeV, where the DD reactivity is on a par of that of the DT reaction. Fast deuterium energy distributions were derived from analysis of NES data and confirm acceleration of deuterium beam ions up to energies around 3 MeV, in agreement with theoretical predictions. The high Neutron rates allowed for observations of changes in the fast deuterium populations on a time scale of 50 ms. Correlations were seen between fast deuterium ions at different energies and magnetohydrodynamic activities, such as monster sawtooth crashes and toroidal Alfven eigenmodes.
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Triton burn-up Neutron Emission in JET low current plasmas
Journal of Physics D: Applied Physics, 2008Co-Authors: Henrik Sjostrand, Luca Giacomelli, Sean Conroy, G Gorini, H. Henriksson, Jan Källne, Göran Ericsson, Anders Hjalmarsson, D Palma, Sergey PopovichevAbstract:The 14 MeV Neutron Emission from JET deuterium discharges is analysed on the basis of the information on all Neutron diagnostics available on JET. This Emission is due to the d + t → α + n reaction, mainly, the triton burn-up process, and is used to determine the fast triton confinement. A simplified model for triton burn-up Neutron Emission has been used and provides an adequate description of the 14 MeV Emission. First orbit triton losses are found to amount to 50%, 20% and 10% at Ip = 1 MA, 2 MA and 3 MA, respectively. Neutron Emission spectroscopy measurements with the magnetic proton recoil Neutron spectrometer have detected a contribution to the 14 MeV Emission due to residual tritium. For the selected (low impurity) discharges analysed in this paper 15% of the 14 MeV Emission comes from the residual tritium reactions. It is also found that the residual tritium concentration tends to increase with increasing impurity content.
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Ion temperature and plasma rotation profile effects in the Neutron Emission spectrum
Review of Scientific Instruments, 2004Co-Authors: M Tardocchi, G Gorini, H. Henriksson, Jan KällneAbstract:The instrumental factors and measuring conditions affecting Neutron Emission spectrometry measurements of tokamak plasmas are described and analyzed. The measured energy broadening and shift of the Neutron Emission is used to deduce ion temperature (Ti) and toroidal plasma rotation velocity (Vt) representing average (effective) values for the nonuniform plasma volume viewed. Analytical expressions are derived for the relationship between the line-volume integrated effective temperature (Teff) and the radial profile Ti(r) for the case of thermal plasmas with isotropic Neutron Emission; effects on Teff due to spectral broadening from the radial dependence Vt(r) were also considered. The analysis method presented here is applied to high quality data obtained with the magnetic proton recoil Neutron spectrometer installed at Joint European Torus for measurements of deuterium–tritium plasmas. Similarly, cases of anisotropic Neutron Emission were quantitatively assessed.
A. Aydin - One of the best experts on this subject based on the ideXlab platform.
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Neutron Emission Spectra of Some Structural Fusion Materials at 26.8 and 45.2 MeV Alpha Incident Energies
Journal of Fusion Energy, 2010Co-Authors: A. Kaplan, A. Aydin, H. BüyükusluAbstract:In this study, Neutron-Emission spectra produced by ( α , xn ) reactions for some structural fusion materials such as ^27Al, ^53Cr, ^56Fe and ^58,60,62Ni have been investigated. Hybrid model, geometry dependent hybrid model and full exciton model have been used to calculate the pre-equilibrium Neutron-Emission spectra. For the reaction equilibrium component, Weisskopf–Ewing model calculations have been preferred. The mean free path parameter’s effect for ( α , xn ) Neutron-Emission spectra has been examined. The obtained results have been discussed and compared with the available experimental data and found agreement with each other.
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Neutron Emission Spectra of ^104,105,106,108,110Pd Isotopes for (p,xn) Reactions at 21.6 MeV Proton Incident Energy
Journal of Fusion Energy, 2010Co-Authors: H. Büyükuslu, A. Kaplan, A. Aydin, G. YıldırımAbstract:Palladium, which is a rare and lustrous silvery-white color from precious metals, plays important role in fusion–fission reactions and different fields of nuclear technology. In addition, it is used for not only cold fusion experiments but also separation of hydrogen isotopes researches for fusion reactors. In this study, Neutron-Emission spectra produced by (p,xn) reactions for structural fusion material ^104,105,106,108,110Pd isotopes have been investigated by a proton beam at 21.6 MeV. Moreover, multiple pre-equilibrium mean free paths constant from internal transition, and the pre-equilibrium and equilibrium level density parameters have been analyzed for some (p,xn) Neutron-Emission spectra calculated. New evaluated hybrid model and geometry dependent hybrid model, full exciton model and cascade exciton model were used to calculate the pre-equilibrium Neutron-Emission spectra. For the reaction equilibrium component, Weisskopf–Ewing model calculations were preferred. The obtained results have been discussed and compared with the available experimental data and found agreement with each other.
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The equilibrium and preequilibrium Neutron-Emission spectra of some structural fusion materials for (n, xn) reactions up to 16 MeV energy
Physics of Atomic Nuclei, 2009Co-Authors: A. Kaplan, A. AydinAbstract:In this study, Neutron-Emission spectra produced by ( n , xn ) reactions for some structural fusion materials as ^27Al, ^51V, ^52Cr, ^55Mn, and ^56Fe have been investigated by a Neutron beam up to 16 MeV. Multiple preequilibrium mean-free-path constant from internal transition and the preequilibrium and equilibrium level-density parameters have been investigated for some ( n , xn ) Neutron-Emission spectra calculated in this study. Preequilibrium Neutron-Emission spectra were calculated by using new-evaluated hybrid model and geometry-dependent hybrid model, full-exciton model, and cascade-exciton model. The reaction equilibrium component was calculated by Weisskopf-Ewing model. The obtained results have been discussed and compared with the available experimental data and found agreement with each other.
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The equilibrium and preequilibrium Neutron-Emission spectra of some structural fusion materials for (n, xn) reactions up to 16 MeV energy
Physics of Atomic Nuclei, 2009Co-Authors: A. Kaplan, E. Tel, A. AydinAbstract:In this study, Neutron-Emission spectra produced by ( n , xn ) reactions for some structural fusion materials as ^27Al, ^51V, ^52Cr, ^55Mn, and ^56Fe have been investigated by a Neutron beam up to 16 MeV. Multiple preequilibrium mean-free-path constant from internal transition and the preequilibrium and equilibrium level-density parameters have been investigated for some ( n , xn ) Neutron-Emission spectra calculated in this study. Preequilibrium Neutron-Emission spectra were calculated by using new-evaluated hybrid model and geometry-dependent hybrid model, full-exciton model, and cascade-exciton model. The reaction equilibrium component was calculated by Weisskopf-Ewing model. The obtained results have been discussed and compared with the available experimental data and found agreement with each other.
D.r. Mayo - One of the best experts on this subject based on the ideXlab platform.
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Revised prompt Neutron Emission multiplicity distributions for 236,238Pu
Nuclear Physics, 2005Co-Authors: P. Santi, D.h. Beddingfield, D.r. MayoAbstract:Abstract The prompt Neutron Emission multiplicity distributions and average values ( P ν and 〈 ν 〉 , respectively) for nuclei which decay via spontaneous fission have been reevaluated. In the cases of 236Pu and 238Pu, inconsistencies were found in the recommended values for P ν and 〈 ν 〉 that were given in the most recent compilation of Neutron Emission multiplicity distributions from the fission of uranium and transuranium nuclides. In correcting for these inconsistencies, the values of 〈 ν 〉 for 236Pu and 238Pu have now been revised to 2.07 ± 0.13 and 2.19 ± 0.07 , respectively. The corresponding Neutron Emission probabilities for these two nuclei have also been revised in order to take into account the new recommended 〈 ν 〉 values.
P. Santi - One of the best experts on this subject based on the ideXlab platform.
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Reevaluation of Prompt Neutron Emission Multiplicity Distributions for Spontaneous Fission
Nuclear Science and Engineering, 2008Co-Authors: P. Santi, M. MillerAbstract:The prompt Neutron Emission probability distributions and average values (Pν and 〈ν〉, respectively) for nuclei that decay via spontaneous fission have been reevaluated to determine if any significa...
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Revised prompt Neutron Emission multiplicity distributions for 236,238Pu
Nuclear Physics, 2005Co-Authors: P. Santi, D.h. Beddingfield, D.r. MayoAbstract:Abstract The prompt Neutron Emission multiplicity distributions and average values ( P ν and 〈 ν 〉 , respectively) for nuclei which decay via spontaneous fission have been reevaluated. In the cases of 236Pu and 238Pu, inconsistencies were found in the recommended values for P ν and 〈 ν 〉 that were given in the most recent compilation of Neutron Emission multiplicity distributions from the fission of uranium and transuranium nuclides. In correcting for these inconsistencies, the values of 〈 ν 〉 for 236Pu and 238Pu have now been revised to 2.07 ± 0.13 and 2.19 ± 0.07 , respectively. The corresponding Neutron Emission probabilities for these two nuclei have also been revised in order to take into account the new recommended 〈 ν 〉 values.
