Effects of background gas pressure on the dynamics of a nonneutral electron plasma confined in a Malmberg–Penning trap

2000 ◽  
Vol 7 (3) ◽  
pp. 831-838 ◽  
Author(s):  
Edward H. Chao ◽  
Ronald C. Davidson ◽  
Stephen F. Paul ◽  
Kyle A. Morrison
Keyword(s):  
Penning Trap ◽  
Electron Plasma ◽  
Gas Pressure ◽  
Background Gas

Effects of background gas pressure on pure electron plasma dynamics in the electron diffusion gauge experiment

1999 ◽  
Author(s):  
Edward H. Chao ◽  
Ronald C. Davidson ◽  
Stephen F. Paul ◽  
Kyle A. Morrison
Keyword(s):  
Electron Plasma ◽  
Gas Pressure ◽  
Plasma Dynamics ◽  
Electron Diffusion ◽  
Background Gas

Effect of Non-equilibrium Pulsed Ejection of Si Species into Background Gas on the Formation of Si Nanocrystallite and Nanocrystal-film

2011 ◽  
Vol 1305 ◽  
Author(s):  
Ikurou Umezu ◽  
Shunto Okubo ◽  
Akira Sugimura
Keyword(s):  
Laser Ablation ◽  
Film Growth ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Hydrogen Gas ◽  
Gas Pressure ◽  
Spatial Confinement ◽  
The Individual ◽  
Background Gas ◽  
Non Equilibrium

ABSTRACTThe Si nanocrystal-films are prepared by pulsed laser ablation of Si target in a mixture of helium and hydrogen gas. The total gas pressure and hydrogen partial gas pressure were varied to control structure of nanocrystal-film. The surface of Si nanocrystallite was hydrogenated and degree of hydrogenation increased with increasing hydrogen partial gas pressure. The aggregate structure of nanocrystal-film depended on both the total gas pressure and the hydrogen partial gas pressure. The former and the latter alter spatial confinement of Si species during deposition and the surface hydrogenation of individual nanocrystal, respectively. Spatial confinement increases probability of collision between nanocrystals in the plume. While, surface hydrogenation prevents coalescence of nanocrystals. The individual or aggregated nanocrystals formed in the plume reach the substrate and the nanocrystal-film is deposited on the substrate. The non-equilibrium growth processes during pulsed laser ablation are essential for the formation of the surface structure and the subsequent nanocrystal-film growth. Our results indicate that the structure of nanocrystal-film depends on the probabilities of collision and coalescence between nanocrystals in the plume. These probabilities can be varied by controlling the total gas pressure and the hydrogen partial gas pressure.

Formation of a symmetric vortex configuration in a pure electron plasma trapped with a penning trap

2007 ◽  
Vol 174 (1-3) ◽  
pp. 71-76 ◽  
Author(s):  
Akio Sanpei ◽  
Kiyokazu Ito ◽  
Yukihiro Soga ◽  
Jun Aoki ◽  
Yasuhito Kiwamoto
Keyword(s):  
Penning Trap ◽  
Electron Plasma

Non-equilibrium Growth Processes of Porous TiO2 Nanocrystal-films during Pulsed Laser Ablation

2013 ◽  
Vol 1497 ◽  
Author(s):  
Ikurou Umezu ◽  
Nobuyasu Yagi ◽  
Akira Sugimura ◽  
Takehito Yoshida
Keyword(s):  
Laser Ablation ◽  
Pulsed Laser ◽  
Hierarchical Structures ◽  
Pulsed Laser Ablation ◽  
Rutile Phase ◽  
Gas Pressure ◽  
Target Distance ◽  
Structural Formation ◽  
Background Gas ◽  
Non Equilibrium

ABSTRACTWe performed pulsed laser ablation of titanium dioxide (TiO2) target in O2 background gas. Effects of background gas pressure and substrate target distance on the structure of deposited films are clarified. The hierarchical structures are observed when we change scale of observation. The film deposited on the substrate is composed of primary nanocrystal and secondary porous-aggregated-nanostructures. The primary nanocrystal changes from anatase to rutile phase with increasing background gas pressure or substrate target distance. The porosity of secondary aggregated structure increases with increasing background gas pressure or substrate target distance. The similarity between the effects of background gas and substrate target distance indicates that confinement of the plume between target and substrate is important for structural formation. The non-equilibrium aggregation processes of nanocrystals in the plume and on the substrate are essential for the hierarchical structure of the nanocrystal film.

scholarly journals Conducting versus insulating walls in a heavy ion reaction chamber

2003 ◽  
Vol 21 (1) ◽  
pp. 41-46 ◽  
Author(s):  
J.-L. VAY ◽  
S. KAWATA ◽  
T. NAKAMURA ◽  
J. SASAKI ◽  
T. SOMEYA ◽  
...  
Keyword(s):  
Charge State ◽  
Ion Beam ◽  
Charge State Distribution ◽  
Electron Plasma ◽  
Heavy Ion ◽  
Reaction Chamber ◽  
Gas Pressure ◽  
State Distribution

We first pay attention to the inflight charge state distribution in a Pb ion beam propagating in a reactor-sized chamber delimited by metallic walls. We thus compare Livermore (code BIC) and Orsay (code BPIC) distributions in the presence of a residual Flibe gas pressure. Next, we replace the electron plasma due to Flibe ionization by a gliding plasma produced by the polarization of the incoming ion beam on insulating walls. Corresponding electrons, when attracted by the beam, are demonstrated to yield a very efficient current neutralization.

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