Energy Dependent Growth Rates of AIN using Pulsed Supersonic Jets

1997 ◽  
Vol 482 ◽  
Author(s):  
V. W. Ballarotto ◽  
M. E. Kordesch
Keyword(s):  
Growth Rate ◽  
Kinetic Energy ◽  
Film Growth ◽  
High Energy ◽  
Supersonic Jets ◽  
Number Density ◽  
Ammonia Gas ◽  
Dependent Growth ◽  
Energy Dependent

AbstractAIN films were grown on Si< 100 >, using unskimmed pulsed supersonic jets of ammonia and trimethylaluminum (TMA). By seeding the ammonia gas in hydrogen or helium, several different energies of the N precursor were used to examine the effect of N kinetic energy on the growth rate of AIN. The energy of the Al precursor, TMA, was 130 meV in all cases. The highest growth rate (0.115 μm/hr) was achieved with the high energy ammonia jet. The role of number density on film growth is discussed.

scholarly journals Study of High-Energy Fission in Inverse Kinematics

2019 ◽  
Vol 223 ◽  
pp. 01037
Author(s):  
G. Mantovani ◽  
D. Ramos ◽  
M. Caamaño ◽  
A. Lemasson ◽  
M. Rejmund ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Excitation Energy ◽  
Shell Structure ◽  
Inverse Kinematics ◽  
High Energy ◽  
Total Kinetic Energy ◽  
High Excitation Energy ◽  
High Excitation ◽  
Shell Effects

Fission at low excitation energy, is a process in which both macroscopic and microscopic aspects are involved. Some features in the total kinetic energy and in the N/Z distributions of the fragments, commonly associated with shell effects, came out in a series of recent experiments with high excitation energy fusionfission reactions in inverse kinematics. In the latest experiment of this campaign, a study of high-energy fission and quasi-fission between a 238U beam and a series of light targets was carried out by using the aforementioned technique, in order to probe the role of the shell structure in these processes.

scholarly journals Study of Electron Beam on Electron Cyclotron Waves with AC Field in the Magnetosphere of Uranus

2017 ◽  
Vol 6 (4) ◽  
pp. 90-100
Author(s):  
R. Kaur ◽  
R. S. Pandey
Keyword(s):  
Growth Rate ◽  
High Energy ◽  
Electron Cyclotron ◽  
Magnetic Field Direction ◽  
Number Density ◽  
Temperature Anisotropy ◽  
Real Frequency ◽  
Oblique Propagation ◽  
High Energy Tail ◽  
Electron Cyclotron Waves

In this paper, we investigate the electromagnetic electron cyclotron (EMEC) waves in the magnetosphere of Uranus. By using the method of characteristic solution, the expression for dispersion relation is drawn. Following kinetic approach, the growth rate and real frequency of EMEC waves is studied theoretically, considering the injection of cold plasma beam in the Uranian system. The observations made by a space probe launched by NASA, Voyager 2, showed unusual orientation of planet’s spin axis and presence of more particles in high energy tail in Uranian magnetospheric plasma. Therefore, in this paper Kappa distribution is employed instead of usual Maxwellian distribution. The study is extended to the parallel as well as the oblique propagation of EMEC waves with variation in temperature anisotropy, number density of electrons and angle of propagation with respect to magnetic field direction. It is found that these parameters support the growth rate of EMEC waves. But response of real frequency of these waves is not same as that of growth rate for all the cases. Numerical analysis also revealed that as the ratio of number density of cold to hot plasma increases growth rate of EMEC waves also increases. Thus, denser the beam is injected, more the growth can be observed. These results are appropriate for applications to space plasma environments and magnetospheric regimes for detailed comparative planetary study.

scholarly journals The role of resonant plasma instabilities in the evolution of blazar induced pair beams

2021 ◽  
Author(s):  
Roy Perry ◽  
Yuri Lyubarsky
Keyword(s):  
Growth Rate ◽  
Specific Property ◽  
High Energy ◽  
Opening Angle ◽  
Oblique Waves ◽  
Very High Energy ◽  
Instability Growth ◽  
Beam Plasma Instability ◽  
High Energy Emission

Abstract The fate of relativistic pair beams produced in the intergalactic medium by very-high energy emission from blazars remains controversial in the literature. The possible role of resonance beam plasma instability has been studied both analytically and numerically but no consensus has been reached. In this paper, we thoroughly analyze the development of this type of instability. This analysis takes into account that a highly relativistic beam loses energy only due to interactions with the plasma waves propagating within the opening angle of the beam (we call them parallel waves), whereas excitation of oblique waves results merely in an angular spreading of the beam, which reduces the instability growth rate. For parallel waves, the growth rate is a few times larger than for oblique ones, so they grow faster than oblique waves and drain energy from the beam before it expands. However, the specific property of extragalactic beams is that they are extraordinarily narrow; the opening angle is only Δθ ∼ 10−6 − 10−5. In this case, the width of the resonance for parallel waves, ∝Δθ2, is too small for them to grow in realistic conditions. We perform both analytical estimates and numerical simulations in the quasilinear regime. These show that for extragalactic beams, the growth of the waves is incapable of taking a significant portion of the beam’s energy. This type of instability could at best lead to an expansion of the beam by some factor but the beam’s energy remains nearly intact.

Effect of Si2H6 as a gas phase additive to increase growth rate of a-Si:H films and solar cells

2012 ◽  
Vol 1426 ◽  
pp. 415-420 ◽  
Author(s):  
Lala Zhu ◽  
Ujjwal K Das ◽  
Chandan Das ◽  
Steven S Hegedus
Keyword(s):  
Growth Rate ◽  
Gas Phase ◽  
Film Growth ◽  
Optical Emission ◽  
High Energy ◽  
Gas Mixtures ◽  
Layer Growth ◽  
Rf Power ◽  
Defect Parameter ◽  
Cell Efficiency

ABSTRACTWe have studied the growth rate enhancement of a-Si:H films using Si2H6 as a gas phase additive to SiH4+ H2 gas mixtures using relatively low pressure and standard 13.56 MHz RF power. With the addition of 1.7% Si2H6 in the gas mixtures (10% more Si atoms into the chamber), the a-Si:H film growth rate increased by ∼30% at 1.25 Torr and ∼60% at 2.5 Torr. The optical emission spectroscopy (OES) exhibits reduction of SiH* intensity with addition of Si2H6, which indicates the reduction of high energy electron impacts with Si containing molecules. The microstructural defect parameter (fraction of dihydride bonding in the film) appears to decrease with increase of RF power (i.e. increase of growth rate). Similar a-Si:H p-i-n cell efficiency 7-8% is achieved with and without enhanced i layer growth rate with the Si2H6additive.

Study on the role of tarnishing film in stress-corrosion cracking of brass in Mattsson's solution

2010 ◽  
Vol 25 (5) ◽  
pp. 991-998 ◽  
Author(s):  
Cheng Zhang ◽  
Yanjing Su ◽  
Lijie Qiao ◽  
Wuyang Chu
Keyword(s):  
Growth Rate ◽  
Crack Initiation ◽  
Tensile Stress ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Film Growth ◽  
Corrosion Cracking ◽  
Hydrogen Charging ◽  
Induced Stress

In this paper, the influence of tarnishing film-induced stress and tarnishing film-induced brittle cracking on stress-corrosion cracking (SCC) of brass in Mattsson’s solution are investigated using hydrogen charging. Results showed that the SCC susceptibility of brass in Mattsson’s solution increased with the increase of tarnishing film-induced tensile stress. Also, the film-induced brittle cracking showed little effect on SCC susceptibility. From the results obtained, an improved SCC mechanism is proposed to explain the role of the tarnishing film-induced stress and the film-induced brittle cracking in SCC of brass in Mattsson’s solution. It seems that the film-induced brittle cracking is responsible for crack initiation of ductile brass. Also, the SCC susceptibility of brass in Mattsson’s solution was controlled by the growth rate of tarnishing film. Hydrogen enhanced the SCC susceptibility, which can be ascribed to the fact that hydrogen facilitates the tarnishing film growth.

scholarly journals Hadronic jet models today

2010 ◽  
Vol 6 (S275) ◽  
pp. 59-67 ◽  
Author(s):  
Marek Sikora
Keyword(s):  
Kinetic Energy ◽  
Crucial Role ◽  
High Energy ◽  
Matter Content ◽  
Energy Spectra ◽  
Synchrotron Emission ◽  
Relativistic Jets ◽  
Electrons And Positrons ◽  
Adiabatic Cooling

AbstractThe matter content of relativistic jets in AGNs is dominated by a mixture of protons, electrons, and positrons. During dissipative events these particles tap a significant portion of the internal and/or kinetic energy of the jet and convert it into electromagnetic radiation. While leptons – even those with only mildly relativistic energies – can radiate efficiently, protons need to be accelerated up to energies exceeding 1016–19 eV to dissipate radiatively a significant amount of energy via either trigerring pair cascades or direct synchrotron emission. Here I review various constraints imposed on the role of hadronic non-adiabatic cooling processes in shaping the high energy spectra of blazars. It will be argued that protons, despite being efficiently accelerated and presumably playing a crucial role in jet dynamics and dissipation of the jet kinetic energy to the internal energy of electrons and positrons, are more likely to remain radiatively passive in AGN jets.

Modifications of a JEOL 2000EX TEM for insSitu surface studies

1993 ◽  
Vol 51 ◽  
pp. 640-641
Author(s):  
Michael T. Marshall ◽  
Xianghong Tong ◽  
J. Murray Gibson
Keyword(s):  
Electron Diffraction ◽  
Surface Science ◽  
Film Growth ◽  
High Vacuum ◽  
High Energy ◽  
Energy Electron ◽  
Ultra High Vacuum ◽  
Transmission Electron ◽  
Fundamental Insight

We have modified a JEOL 2000EX Transmission Electron Microscope (TEM) to allow in-situ ultra-high vacuum (UHV) surface science experiments as well as transmission electron diffraction and imaging. Our goal is to support research in the areas of in-situ film growth, oxidation, and etching on semiconducter surfaces and, hence, gain fundamental insight of the structural components involved with these processes. The large volume chamber needed for such experiments limits the resolution to about 30 Å, primarily due to electron optics. Figure 1 shows the standard JEOL 2000EX TEM. The UHV chamber in figure 2 replaces the specimen area of the TEM, as shown in figure 3. The chamber is outfitted with Low Energy Electron Diffraction (LEED), Auger Electron Spectroscopy (AES), Residual Gas Analyzer (RGA), gas dosing, and evaporation sources. Reflection Electron Microscopy (REM) is also possible. This instrument is referred to as SHEBA (Surface High-energy Electron Beam Apparatus).The UHV chamber measures 800 mm in diameter and 400 mm in height. JEOL provided adapter flanges for the column.

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