scholarly journals Energy loss of protons and He2+ beams in plasmas

2014 ◽  
Vol 16 (6) ◽  
pp. 1085-1090
Keyword(s):  
Hydrogen Plasma ◽  
Argon Plasma ◽  
Alpha Particles ◽  
Free Electrons ◽  
Ionization Degree ◽  
Saha Equation ◽  
Hartree Fock ◽  
Plasma Target ◽  
Strength Functions ◽  
Bound Electrons

<div> <p>In this work, the stopping power due to free and bound electrons in a plasma target is analyzed for two different kinds of projectile, protons and alpha particles. The stopping of free electrons is calculated using the dielectric formalism, well described in previous literature. In the case of bound electrons, Hartree-Fock methods and oscillator strength functions are used. The ionization degree of the plasma target is calculated using the Saha equation. Differences between the two methods of calculations for bound electrons are shown in noble gases. The influence of ionization is also estimated for argon plasma. Finally, we compare our calculations with two experiments. In the first one the stopping is calculated for protons in polyethylene plasma, and the second one the stopping is obtained for alpha particles in hydrogen plasma. In both cases, a good agreement with the experimental data is found.</p> </div> <p>&nbsp;</p>

scholarly journals Electronic stopping of protons in xenon plasmas due to free and bound electrons

2013 ◽  
Vol 31 (1) ◽  
pp. 105-111 ◽  
Author(s):  
Manuel D. Barriga-Carrasco ◽  
David Casas
Keyword(s):  
Oscillator Strength ◽  
Close Agreement ◽  
Noble Gases ◽  
Previous Literature ◽  
Free Electrons ◽  
Hartree Fock ◽  
Plasma Target ◽  
Strength Functions ◽  
Bound Electrons

AbstractIn this work, proton stopping due to free and bound electrons in a plasma target is analyzed. The stopping of free electrons is calculated using the dielectric formalism, well described in previous literature. In the case of bound electrons, Hartree-Fock methods and oscillator strength functions are used. Differences between both stopping, due to free and bound electrons, are shown in noble gases. Then, enhanced plasma stopping can be easily estimated from target ionization. Finally, we compare our calculations with an experiment in xenon plasmas finding a close agreement.

scholarly journals Energy loss of protons in hydrogen plasma

2018 ◽  
Vol 36 (1) ◽  
pp. 98-104 ◽  
Author(s):  
R. Cheng ◽  
X. Zhou ◽  
Y. Wang ◽  
Y. Lei ◽  
Y. Chen ◽  
...  
Keyword(s):  
Energy Loss ◽  
Electron Density ◽  
Potential Application ◽  
Hydrogen Plasma ◽  
Hydrogen Gas ◽  
Experimental Results ◽  
Free Electrons ◽  
Error Limit ◽  
Bound Electrons ◽  
Good Agreement

AbstractThis paper reports the measurement of the energy loss of protons at the energy of 100 keV penetrating a partially ionized hydrogen plasma. The plasma of ne ≈ 1015–16 cm−3; Te ≈ 1–2 eV and lifetime of about 8 µs is created by the hydrogen gas discharge. The experimental results show an increase of a factor of 2.8 in the energy loss, which are in good agreement with the Bethe, Standard Stopping Model, Li–Petrasso and Vlasov models’ predictions within the error limit. The Bethe–Bloch Coulomb logarithm term is found to increase by a factor of 4.0 for free electrons as compared with the situation where bound electrons prevail. The potential application of protons energy loss for diagnosing the electron density in plasma is proposed too.

scholarly journals Thermodynamic of Liquid Iron Ore Reduction by Hydrogen Thermal Plasma

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1051 ◽  
Author(s):  
Masab Naseri Seftejani ◽  
Johannes Schenk
Keyword(s):  
Iron Oxide ◽  
Liquid Iron ◽  
Thermal Plasma ◽  
Iron Ore ◽  
Hydrogen Plasma ◽  
Reduction Rate ◽  
Plasma Arc ◽  
Ionization Degree ◽  
Reduction Reactions ◽  
Plasma State

The production of iron using hydrogen as a reducing agent is an alternative to conventional iron- and steel-making processes, with an associated decrease in CO2 emissions. Hydrogen plasma smelting reduction (HPSR) of iron ore is the process of using hydrogen in a plasma state to reduce iron oxides. A hydrogen plasma arc is generated between a hollow graphite electrode and liquid iron oxide. In the present study, the thermodynamics of hydrogen thermal plasma and the reduction of iron oxide using hydrogen at plasma temperatures were studied. Thermodynamics calculations show that hydrogen at high temperatures is atomized, ionized, or excited. The Gibbs free energy changes of iron oxide reductions indicate that activated hydrogen particles are stronger reducing agents than molecular hydrogen. Temperature is the main influencing parameter on the atomization and ionization degree of hydrogen particles. Therefore, to increase the hydrogen ionization degree and, consequently, increase of the reduction rate of iron ore particles, the reduction reactions should take place in the plasma arc zone due to the high temperature of the plasma arc in HPSR. Moreover, the solubility of hydrogen in slag and molten metal are studied and the sequence of hematite reduction reactions is presented.

scholarly journals Multiply ionized carbon plasmas with index of refraction greater than one

2007 ◽  
Vol 25 (1) ◽  
pp. 47-51 ◽  
Author(s):  
J. FILEVICH ◽  
J. GRAVA ◽  
M. PURVIS ◽  
M.C. MARCONI ◽  
J.J. ROCCA ◽  
...  
Keyword(s):  
Laser Interferometry ◽  
General Assumption ◽  
Capillary Discharge ◽  
Index Of Refraction ◽  
Carbon Ions ◽  
Free Electrons ◽  
X Ray ◽  
Computer Calculations ◽  
Approximation Analysis ◽  
Bound Electrons

For decades the analysis of interferometry have relied on the approximation that the index of refraction in plasmas is due solely to the free electrons. This general assumption makes the index of refraction always less than one. However, recent soft x-ray laser interferometry experiments with Aluminum plasmas at wavelengths of 14.7 nm and 13.9 nm have shown fringes that bend the opposite direction than would be expected when using that approximation. Analysis of the data demonstrated that this effect is due to bound electrons that contribute significantly to the index of refraction of multiply ionized plasmas, and that this should be encountered in other plasmas at different wavelengths. Recent studies of Silver and Tin plasmas using a 46.9 nm probe beam generated by a Ne-like Ar capillary discharge soft-ray laser identified plasmas with an index of refraction greater than one, as was predicted by computer calculations. In this paper we present new interferometric results obtained with Carbon plasmas at 46.9 nm probe wavelength that clearly show plasma regions with an index of refraction greater than one. Computations suggest that in this case the phenomenon is due to the dominant contribution of bound electrons from doubly ionized carbon ions to the index of refraction. The results reaffirm that bound electrons can strongly influence the index of refraction of numerous plasmas over a broad range of soft x-ray wavelengths.

Optical Activation of Erbium Doped Porous Silicon by Hydrogen Plasma Treatment

1997 ◽  
Vol 486 ◽  
Author(s):  
T. Dejima ◽  
R. Saito ◽  
S. Yugou ◽  
H. Isshiki ◽  
T. Kimura
Keyword(s):  
Porous Silicon ◽  
Crystalline Silicon ◽  
Hydrogen Plasma ◽  
Argon Plasma ◽  
Ethanol Solution ◽  
Ir Absorption ◽  
Annealing Atmosphere ◽  
Hydrogen Atoms ◽  
Optical Activation ◽  
Amorphous Surface

AbstractEr3+;-doped porous silicon (Er:PS) shows strong room temperature emissions at ˜ 1.54μm. However, its spectrum is usually much broader than that of Er-doped crystalline silicon (fullwidth at half maximum - FWHM - is ˜ 10 nm). It is probably because Er ions are located in amorphous phases. We report in this paper that strong and very sharp Er3+ 1.54μm emissions are obtained, when Er:PS samples are treated in a hydrogen plasma. Porous silicon layers are formed by anodic etching and then doped with Er3+ ions in an ErCl3/ethanol solution by an electrochemical method, and then treated in a hydrogen plasma at ˜ 1000°C from 0.5 min to 90 min for the optical activation. Several sharp peaks are observed at 20K, of which the strongest peak is located at 1.538 μm with an FWHM less than 1 nm. This value is comparable to that obtained from Er3+-doped crystalline silicon formed by means of molecular beam epitaxy (MBE) or ion implantation. Comparisons are made among hydrogen plasma, argon plasma, H2 flow and vacuum for the post-dope annealing atmosphere. Fourier-transform infrared (FT-IR) absorption and secondary ions mass spectrometry (SIMS) measurements are also carried out. We conclude that preferential etching of amorphous surface layers, and termination of dangling bonds of silicon nanocrystallites with hydrogen atoms and formation of Er-H complexes may be responsible for the strong and sharp Er3+-related luminescence.

Luminescence from evaporated films of CdS

1969 ◽  
Vol 47 (23) ◽  
pp. 2591-2595 ◽  
Author(s):  
J. Conradi
Keyword(s):  
Surface Concentration ◽  
Peak Position ◽  
Luminescence Spectra ◽  
Free Electrons ◽  
Pulsed Electron Beam ◽  
Simultaneous Emission ◽  
Electron Beam Excitation ◽  
Bound Electrons ◽  
Concentration Of Electrons ◽  
Beam Excitation

Luminescence spectra from evaporated films of CdS are obtained under pulsed electron beam excitation. The transitions giving rise to the luminescence are identified as resulting from the recombination of bound electrons with bound holes and the simultaneous emission of n LO phonons (n = 0, 1, 2, … ), and the recombination of free electrons with bound holes. The addition of a 2000 Å thick coating of SiOx on top of the CdS is shown to produce a degenerate surface concentration of electrons which shifts the peak position of the free–bound transition to higher energies.

scholarly journals Effect of Atomic Number on Plasma Pinch Properties and Radiative Emissions

2021 ◽  
Vol 2021 ◽  
pp. 1-5
Author(s):  
Walid Sahyouni ◽  
Alaa Nassif
Keyword(s):  
Atomic Number ◽  
Plasma Focus ◽  
Dense Plasma ◽  
Ion Beam ◽  
Hydrogen Plasma ◽  
Argon Plasma ◽  
The State ◽  
Dense Plasma Focus ◽  
Radiation Emission ◽  
Plasma Pinch

The aim of the research is to examine the dependence of plasma pinch properties and radiation emissions on the atomic number of the operating gas within the dense plasma focus device (NX2) when using hydrogen and argon gases. Simulation was performed with Lee’s code on an NX2 dense plasma focus at a constant gas pressure value ( P 0 = 0.5   torr ). The results showed that the minimum radius of the plasma focus in the case of the hydrogen plasma pinch was 0.30 cm and in the case of the argon plasma pinch 0.17 cm, and this affected the value of the radiation emission as it was 7.8 × 10 − 6   J and 11 J for the hydrogen and argon pinch, respectively. The energy of the ion beam released by the breakdown of the plasma pinch was found as E n = 23.8   J in the state of hydrogen and E n = 105   J in the state of argon.

scholarly journals Ionization potential depression and ionization balance in dense carbon plasma under solar and stellar interior conditions

2020 ◽  
Vol 644 ◽  
pp. A92
Author(s):  
Jiaolong Zeng ◽  
Yongjun Li ◽  
Yong Hou ◽  
Cheng Gao ◽  
Jianmin Yuan
Keyword(s):  
Ionization Potential ◽  
Dense Plasma ◽  
Solar Interior ◽  
Hydrogen Atoms ◽  
Free Electrons ◽  
Ionization Degree ◽  
Stellar Interior ◽  
Plasma Screening ◽  
Ionization Balance ◽  
Carbon Plasma

Recent quantitative experiments on the ionization potential depression (IPD) in dense plasma show that the observational results are difficult to explain with the widely used analytical models for plasma screening. Here, we investigate the effect of plasma screening on the IPD and ionization balance of dense carbon plasma under solar and stellar interior conditions using our developed consistent nonanalytical model. The screening potential can be primarily attributed to the free electrons in the plasma and is determined by the microspace distribution of these free electrons. The ionization balance is determined by solving the Saha equation, including the effect of IPD. The predicted IPD and average ionization degree are larger than those obtained using the Stewart–Pyatt model for mass densities that are greater than 3.0 g cm−3. Under solar interior conditions, our results are in better agreement with the Ecker–Kröll model at electron temperatures and densities lower than 250 eV and 2.1 × 1023 cm−3 and in the best agreement with the ion-sphere model at 303 eV and 4.3 × 1023 cm−3. Finally, our results are compared with those obtained via a recent experiment on a CH-mixture plasma that has been compressed six times. The predicted average ionization degree of C in a CH mixture agrees better with the experiment than the Stewart–Pyatt and Thomas–Fermi models when the screening from free electrons contributed by hydrogen atoms is included. Our results provide useful information concerning the ionization balance and can be applied to investigate the opacity and equations of state for dense plasma under the solar and stellar interior conditions.

Control Rod Blades Size Reduction Using Underwater Plasma Cutting and its Effects on Boron Carbide Powder Scattering

2020 ◽  
Author(s):  
Yassine Serbouti ◽  
Keisuke Kurihara ◽  
Yutaka Kometani ◽  
Masatoshi Itagaki ◽  
Makoto Tatemura
Keyword(s):  
Boron Carbide ◽  
Cross Sections ◽  
Hydrogen Plasma ◽  
Argon Plasma ◽  
Size Reduction ◽  
Carbide Powder ◽  
Neutron Absorber ◽  
Control Rod ◽  
Last Stage ◽  
Actual Control

Abstract Control rod blades are comprised of a stainless steel sheath, which contains neutron absorber tubes (filled with boron carbide powder). During decommissioning, the first stage of size reduction consists of cutting the connector (bottom portion) of the control rod, while the second stage consists of separating the blades of the control rod by cutting through the tie rod. The last stage consists of segmenting the control rod blades by cutting through absorber tubes. In this study, the control rod blades segmentation (last stage of size reduction) is investigated using an actual control rod (unused). During the experiments, we used a forming press on the cut locations followed by a plasma arc cutting underwater. The purpose of this cutting technique is to minimize the scattering of boron carbides into water by using the stainless sheath melt to seal the absorber tubes. After the segmentation, we confirmed the sealing of the absorber tubes by visually examining the cut cross-sections. The water analysis showed that the boron carbide scattering was relatively low (only 0.07% of the total boron carbides was scattered). Finally, we confirmed that the off-gas emission is considerably reduced by using Argon plasma instead of Argon-Hydrogen plasma.

scholarly journals Stopping power of a heterogeneous warm dense matter

2016 ◽  
Vol 34 (2) ◽  
pp. 306-314 ◽  
Author(s):  
D. Casas ◽  
A.A. Andreev ◽  
M. Schnürer ◽  
M.D. Barriga-Carrasco ◽  
R. Morales ◽  
...  
Keyword(s):  
Special Kind ◽  
Dense Matter ◽  
Stopping Power ◽  
Free Electrons ◽  
Warm Dense Matter ◽  
Excitation Energies ◽  
Plasma Density Profile ◽  
Individual Contributions ◽  
The Individual ◽  
Bound Electrons

AbstractThe stopping power of warm dense matter (WDM) is estimated by means of the individual contributions of free electrons and bound electrons existing in this special kind of matter, located between classical and degenerate plasmas. For free electrons, the dielectric formalism, well described in our studies, is used to estimate the free electron stopping power. For bound electrons, the mean excitation energy of ions is used. Excitation energies are obtained through atomic calculations of the whole atom or, shell by shell in order to estimate their stopping power. Influence of temperature and density is analyzed in case of an impinging projectile. This influence becomes important for low projectile velocities and is negligible for high ones. Using free and bound electron analysis, the stopping power of an extended WDM is inferred from a dynamical calculation of energy transferred from the projectile to the plasma, where the stopping range is calculated. Finally, this theoretical framework is used to study a typical plasma density profile of a WDM heated by lasers.

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