The Experts below are selected from a list of 177 Experts worldwide ranked by ideXlab platform
Bernard Deconihout - One of the best experts on this subject based on the ideXlab platform.
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Femtosecond field Ion emissIon by surface optical rectificatIon.
Physical review letters, 2007Co-Authors: Angela Vella, Bernard Deconihout, Lorenzo Marrucci, E. SantamatoAbstract:We show that a model based on the surface optical rectificatIon effect associated with the nonlinear response of free electrons may explain quantitatively, without adjustable parameters, all the observed features of the ultrafast laser-assisted field-Ion emissIon from metal tips. Moreover, the same model provides also a plausible explanatIon for the low-fluence ultrafast laser ablatIon recently observed in metal surfaces and nanoparticles. We further test our model with experiments of ultrafast laser-assisted field-Ion emissIon from tungsten tips in the tomographic atom probe.
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Ultrafast Ion emissIon from metallic tip excited by femtosecond laser pulses
Applied Physics Letters, 2006Co-Authors: Angela Vella, M. Gilbert, Ammar Hideur, François Vurpillot, Bernard DeconihoutAbstract:Using femtosecond time resolved measurements of the Ion evaporatIon flux from a metal tip, the authors study the temporal behavior of Ion emissIon a few femtoseconds after the incident ultrashort laser pulse. The authors show that the ultrafast response of surface electrons generates a very short and intense Ion emissIon. Also a weak heating of the specimen was observed leading to the increase of the Ion emissIon rate. The observed ultrafast Ion emissIon is consistent with the model based on the rectificatIon of the optical field at the surface of the material.
Morteza Habibi - One of the best experts on this subject based on the ideXlab platform.
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Hydrogen Ion emissIon studies in 4π plasma focus device space
Radiation Physics and Chemistry, 2020Co-Authors: Mehdi Sohrabi, Zahra Soltani, Morteza HabibiAbstract:Abstract Plasma focus devices (PFD) produce copious flux of Ions in particular hydrogen Ions in 4π space. To achieve dense plasma pinch and then the emissIon of hydrogen Ions at a voltage of 13 kV, experiments have been carried out at various gas pressures inside the chamber. Discharge current signals were recorded by Rogowski coil to choose only discharges with a high degree of current sheath symmetry and plasma pinch formatIon. Wide-angle 3D images of hydrogen Ion emissIons were efficiently formed for the first time in our laboratory on novel positIon-sensitive panorama mega-size cylindrical polycarbonate image detectors (MS-CPID) processed in self-invented panorama mega-size single-cell electrochemical etching (MS-ECE) systems. Hydrogen Ion emissIon images are simply observed and analyzed by the unaided eyes. Near 4π wide-angle hydrogen Ion image detectIon, iso-fluence contours, fluence on polar angle distributIons, and hydrogen Ion energy estimatIon were studied. MS-CPID/MS-ECE methods are breakthrough Ion image detectIon art and technology for hydrogen Ion plasma mechanism studies with provisIon of 4π positIon-sensitive data matrix bank. Studies confirm 4π hydrogen Ion emissIon from “anode top” and radial Ion run-aways from “anode assembly” forming “hydrogen cathode shadows” on MS-CPIDs making 4π PFD space availability evident for full-scope large-scale advanced hydrogen Ion mechanism studies and applicatIons.
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Breakthrough in 4π Ion emissIon mechanism understanding in plasma focus devices.
Scientific reports, 2016Co-Authors: Mehdi Sohrabi, Arefe Zarinshad, Morteza HabibiAbstract:Ion emissIon angular distributIon mechanisms in plasma focus devices (PFD) have not yet been well developed and understood being due to the lack of an efficient wide-angle Ion distributIon image detectIon system to characterize a PFD space in detail. Present belief is that the acceleratIon of Ions points from “anode top” upwards in forward directIon within a small solid angle. A breakthrough is reported in this study, by mega-size positIon-sensitive polycarbonate Ion image detectIon systems invented, on discovery of 4π Ion emissIon from the “anode top” in a PFD space after plasma pinch instability and radial run-away of Ions from the “anode cathodes array” during axial acceleratIon of plasma sheaths before the radial phase. These two Ion emissIon source mechanisms behave respectively as a “Point Ion Source” and a “Line Ion Source” forming “Ion Cathode Shadows” on mega-size detectors. We believe that the inventIons and discoveries made here will open new horizons for advanced Ion emissIon studies towards better mechanisms understanding and in particular will promote efficient applicatIons of PFDs in medicine, science and technology.
Angela Vella - One of the best experts on this subject based on the ideXlab platform.
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Femtosecond field Ion emissIon by surface optical rectificatIon.
Physical review letters, 2007Co-Authors: Angela Vella, Bernard Deconihout, Lorenzo Marrucci, E. SantamatoAbstract:We show that a model based on the surface optical rectificatIon effect associated with the nonlinear response of free electrons may explain quantitatively, without adjustable parameters, all the observed features of the ultrafast laser-assisted field-Ion emissIon from metal tips. Moreover, the same model provides also a plausible explanatIon for the low-fluence ultrafast laser ablatIon recently observed in metal surfaces and nanoparticles. We further test our model with experiments of ultrafast laser-assisted field-Ion emissIon from tungsten tips in the tomographic atom probe.
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Ultrafast Ion emissIon from metallic tip excited by femtosecond laser pulses
Applied Physics Letters, 2006Co-Authors: Angela Vella, M. Gilbert, Ammar Hideur, François Vurpillot, Bernard DeconihoutAbstract:Using femtosecond time resolved measurements of the Ion evaporatIon flux from a metal tip, the authors study the temporal behavior of Ion emissIon a few femtoseconds after the incident ultrashort laser pulse. The authors show that the ultrafast response of surface electrons generates a very short and intense Ion emissIon. Also a weak heating of the specimen was observed leading to the increase of the Ion emissIon rate. The observed ultrafast Ion emissIon is consistent with the model based on the rectificatIon of the optical field at the surface of the material.
Weiguo Liu - One of the best experts on this subject based on the ideXlab platform.
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InvestigatIon of characteristics of non-reductive thermal Ion emissIon of various graphites in thermal IonizatIon mass spectrometry
Analytica Chimica Acta, 2000Co-Authors: Yingkai Xiao, Haizhen Wei, Yinmin Zhou, Yun-hui Wang, Weiguo LiuAbstract:The characteristics of non-reductive thermal Ion emissIon in thermal IonizatIon mass spectrometry for six kinds of graphite with different origins, purity and crystal structure and one high pure carbon powder are studied. The results show that the efficacy of non-reductive thermal Ion emissIon of graphite is weakly related to the purity and particle size of graphite while dependent on the crystal microstructure of graphite. Graphite with a perfect crystal structure has a higher efficiency of non-reductive thermal Ion emissIon.
Yingkai Xiao - One of the best experts on this subject based on the ideXlab platform.
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InvestigatIon of characteristics of non-reductive thermal Ion emissIon of various graphites in thermal IonizatIon mass spectrometry
Analytica Chimica Acta, 2000Co-Authors: Yingkai Xiao, Haizhen Wei, Yinmin Zhou, Yun-hui Wang, Weiguo LiuAbstract:The characteristics of non-reductive thermal Ion emissIon in thermal IonizatIon mass spectrometry for six kinds of graphite with different origins, purity and crystal structure and one high pure carbon powder are studied. The results show that the efficacy of non-reductive thermal Ion emissIon of graphite is weakly related to the purity and particle size of graphite while dependent on the crystal microstructure of graphite. Graphite with a perfect crystal structure has a higher efficiency of non-reductive thermal Ion emissIon.
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InvestigatIon of thermal Ion emissIon characteristics of graphite
International Journal of Mass Spectrometry and Ion Processes, 1991Co-Authors: Yingkai Xiao, Ling JinAbstract:Abstract The thermal Ion emissIon characteristics of graphite have been studied. The intensities of the Ions M2BO+2 and M2Cl+ were greatly enhanced by coating the filament with graphite. This is because the IonizatIon potentials of these Ions were decreased. The graphite characteristics have been applied to isotopic determinatIon of boron by thermal IonizatIon mass spectrometry. It is possible to develop a high precisIon isotopic measurement of chlorine by using the technique of loading graphite.
