scholarly journals Optimization of relativistic laser–ion acceleration

2014 ◽  
Vol 2 ◽  
Author(s):  
J. Schreiber ◽  
F. Bell ◽  
Z. Najmudin
Keyword(s):  
Radiation Pressure ◽  
Pulse Energy ◽  
Laser System ◽  
Target Thickness ◽  
Ion Acceleration ◽  
Essential Property ◽  
Ion Energy ◽  
Starting Point ◽  
Ion Energies ◽  
Acceleration Model

Abstract Experiments have shown that the ion energy obtained by laser–ion acceleration can be optimized by choosing either the appropriate pulse duration or the appropriate target thickness. We demonstrate that this behavior can be described either by the target normal sheath acceleration model of Schreiber et al. or by the radiation pressure acceleration model of Bulanov and coworkers. The starting point of our considerations is that the essential property of a laser system for ion acceleration is its pulse energy and not its intensity. Maybe surprisingly we show that higher ion energies can be reached with reduced intensities.

Physical and Chemical Sputtering at Very Low Ion Energy: the Importance of the Sputtering Threshold

1988 ◽  
Vol 129 ◽  
Author(s):  
Christoph Steinbruchel
Keyword(s):  
Threshold Energy ◽  
Surface Binding ◽  
Ion Energy ◽  
Chemical Sputtering ◽  
Surface Binding Energy ◽  
Physical Sputtering ◽  
Chemical Etch ◽  
Ion Energies ◽  
The Difference ◽  
Physical And Chemical

ABSTRACTA variety of data for physical etching (i.e. sputtering) and for ion-enhanced chemical etching of Si and SiO2 is analyzed in the very-low-ion-energy regime. Bombardment by inert ions alone, by reactive ions, and by inert ions in the presence of reactiveneutrals is considered. In all cases the etch yield follows a square root dependence on the ion energy all the way down to the threshold energy for etching. At the same time, the threshold energy has a non-negligible effect on the etch yield even at intermediate ion energies. The difference between physical and ion-enhanced chemical etch yields can be accounted for by a reduction in the average surface binding energy of the etch products and a corresponding reduction in the threshold energy for etching. These results suggest that, in general, the selectivity for ion-enhanced etch processes relative to physical sputtering can be increased significantly at low ion energy.

scholarly journals Ion Acceleration in Multispecies Targets Driven by Intense Laser Radiation Pressure

2012 ◽  
Vol 109 (18) ◽  
Author(s):  
S. Kar ◽  
K. F. Kakolee ◽  
B. Qiao ◽  
A. Macchi ◽  
M. Cerchez ◽  
...  
Keyword(s):  
Laser Radiation ◽  
Radiation Pressure ◽  
Intense Laser ◽  
Ion Acceleration ◽  
Intense Laser Radiation

scholarly journals Characterisation and Modelling of Ultrashort Laser-Driven Electromagnetic Pulses

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Kwinten Nelissen ◽  
Máté Liszi ◽  
Massimo De Marco ◽  
Valeria Ospina ◽  
István Drotár ◽  
...  
Keyword(s):  
Pulse Energy ◽  
Large Scale ◽  
Laser Intensity ◽  
Laser Energy ◽  
Laser System ◽  
Intense Laser ◽  
Electron Interaction ◽  
Laser Target ◽  
Electromagnetic Pulses ◽  
Target Holder

AbstractRecent advances on laser technology have enabled the generation of ultrashort (fs) high power (PW) laser systems. For such large scale laser facilities there is an imperative demand for high repetition rate operation in symbiosis with beamlines or end-stations. In such extreme conditions the generation of electromagnetic pulses (EMP) during high intense laser target interaction experiments can tip the scale for the good outcome of the campaign. The EMP effects are several including interference with diagnostic devices and actuators as well as damage of electrical components. The EMP issue is quite known in the picosecond (ps) pulse laser experiments but no systematic study on EMP issues at multi-Joule fs-class lasers has been conducted thus far. In this paper we report the first experimental campaign for EMP-measurements performed at the 200 TW laser system (VEGA 2) at CLPU laser center. EMP pulse energy has been measured as a function of the laser intensity and energy together with other relevant quantities such as (i) the charge of the laser-driven protons and their maximum energy, as well as (ii) the X-ray Kα emission coming from electron interaction inside the target. Analysis of experimental results demonstrate (and confirm) a direct correlation between the measured EMP pulse energy and the laser parameters such as laser intensity and laser energy in the ultrashort pulse duration regime. Numerical FEM (Finite Element Method) simulations of the EMP generated by the target holder system have been performed and the simulations results are shown to be in good agreement with the experimental ones.

scholarly journals Investigations on low temperature laser-generated plasmas

2008 ◽  
Vol 26 (2) ◽  
pp. 265-271 ◽  
Author(s):  
F. Caridi ◽  
L. Torrisi ◽  
D. Margarone ◽  
A. Borrielli
Keyword(s):  
Target Surface ◽  
Ion Acceleration ◽  
Ion Temperature ◽  
Free Electron Density ◽  
Ion Energy ◽  
Equilibrium Plasma ◽  
Ablation Yield ◽  
Ion Energy Distributions ◽  
Acceleration Voltage ◽  
Non Equilibrium

AbstractA nanosecond pulsed Nd-Yag laser, operating at an intensity of about 109 W/cm2, was employed to irradiate different metallic solid targets (Al, Cu, Ta, W, and Au) in vacuum. The measured ablation yield increases with the direct current (dc) electrical conductivity of the irradiated target. The produced plasma was characterized in terms of thermal and Coulomb interaction evaluating the ion temperature and the ion acceleration voltage developed in the non-equilibrium plasma core. The particles emission produced along the normal to the target surface was investigated measuring the neutral and the ion energy distributions and fitting the experimental data with the “Coulomb-Boltzmann-shifted” function. Results indicate that the mean energy of the distributions and the equivalent ion acceleration voltage of the non-equilibrium plasma increase with the free electron density of the irradiated element.

Dependence of the ion energy on the parameters of the laser pulse and target in the radiation-pressure-dominated regime of acceleration

2010 ◽  
Vol 36 (1) ◽  
pp. 15-29 ◽  
Author(s):  
E. Yu. Echkina ◽  
I. N. Inovenkov ◽  
T. Zh. Esirkepov ◽  
F. Pegoraro ◽  
M. Borghesi ◽  
...  
Keyword(s):  
Laser Pulse ◽  
Radiation Pressure ◽  
Ion Energy

Influence of energy losses on charge distribution of fast ions passing through solid matter

2020 ◽  
Vol 34 (14) ◽  
pp. 2050150
Author(s):  
Yu. A. Belkova ◽  
N. V. Novikov ◽  
Ya. A. Teplova
Keyword(s):  
Charge Distribution ◽  
Cross Sections ◽  
Heavy Ions ◽  
Nuclear Charge ◽  
Target Thickness ◽  
Energy Losses ◽  
Ion Energy ◽  
Fast Ions ◽  
Maximum Value ◽  
Ion Energy Losses

The charge distribution of fast multicharged ions passing through a matter is studied taking ion energy losses into account. Within the framework of the proposed method, we show that the changes in the charge exchange cross-sections, caused by the decreasing of ion energy, affect the process of the formation of the equilibrium ion charge distribution. The target thickness, required for obtaining the equilibrium ion charge distribution, reaches the maximum value for ions without electrons and hydrogen-like ions. The equilibrium target thickness increases with increasing in ion nuclear charge and energy and for fast heavy ions becomes comparable with their range.

High quality ion acceleration from a double-layer target dominated by the radiation pressure of a transversely Gaussian laser pulse

2010 ◽  
Vol 17 (10) ◽  
pp. 103107 ◽  
Author(s):  
Xue-Ren Hong ◽  
Bai-Song Xie ◽  
Shan Zhang ◽  
Hai-Cheng Wu ◽  
Aimierding Aimidula ◽  
...  
Keyword(s):  
Laser Pulse ◽  
Double Layer ◽  
Radiation Pressure ◽  
Ion Acceleration ◽  
High Quality

Dry Etch Damage in GaAs P-N Junctions

1991 ◽  
Vol 240 ◽  
Author(s):  
S. J. Pearton ◽  
F. Ren ◽  
C. R. Abernathy ◽  
T. R. Fullowan ◽  
J. R. Lothian
Keyword(s):  
Plasma Etching ◽  
Ion Bombardment ◽  
Plasma Exposure ◽  
Base Resistance ◽  
Ion Energy ◽  
Ion Energies ◽  
A Minor ◽  
P Type ◽  
Dry Etch ◽  
Very High

ABSTRACTGaAs p-n junction mesa-diode structures were fabricated so that both n- and p-type layers could be simultaneously exposed to either O2 or H2 discharges. This simulates the ion bombardment during plasma etching with either CCl2F2/O2 or CH4/H2 mixtures. The samples were exposed to 1 mTorr discharges for period of 1–20 min with DC biases of -25 to -400V on the cathode. For O2 ion bombardment, the collector resistance showed only minor (≤10%) increases for biases up to -200 V and more rapid increases thereafter. In our structure, this indicates that bombardment-induced point defects penetrate at least 500 Å of GaAs for ion energies of ≥200eV. The base resistance displayed only a minor increase (∼10%) over the pre-exposure value even for O+ ion energies of 375 eV, due to the very high doping (1020 cm−3 ) in the base. More significant increases in both collector and base resistances were observed for hydrogen ion bombardment due to hydrogen passivation effects. We will give details of this behaviour as a function of ion energy, plasma exposure time and post-treatment annealing temperature.

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