scholarly journals Energy loss and effective charge of low-energy oxygen ions in partially ionized plasma

2000 ◽  
Vol 18 (4) ◽  
pp. 639-646
Author(s):  
K. NISHIGORI ◽  
U. NEUNER ◽  
M. TAKIZAWA ◽  
M. KOJIMA ◽  
T. SAGAMI ◽  
...  
Keyword(s):  
Energy Loss ◽  
Charge Distribution ◽  
Effective Charge ◽  
Low Energy ◽  
Stopping Power ◽  
Oxygen Ions ◽  
Power Equation ◽  
Slow Ions ◽  
Partially Ionized ◽  
Peak Value

This article reports on the interaction between slow ions and a partially ionized plasma. Temporal evolutions of energy loss and charge distribution of 2.4 MeV oxygen beams in the laser-induced polyethylene plasma were measured. The charge distribution showed strong stripping ability in the early phase of the plasma. Stopping power deduced from the experimental energy loss was 1.9 times larger than that for the solid. The effective charge of the projectile ion was estimated from the yields of 4+ and 6+ states. The peak value of the effective charge was 1.4 times larger than that of the solid. The stopping power equation given by Sigmund was extended for the partially ionized plasma and it could reproduce the measured energy loss.

NEUTRINO ENERGY LOSS AT MATTER-RADIATION DECOUPLING PHASE

2009 ◽  
Vol 24 (11n13) ◽  
pp. 1051-1054
Author(s):  
UNGKU FERWANI SALWA UNGKU IBRAHIM ◽  
NOR SOFIAH AHMAD ◽  
NORHASLIZA YUSOF ◽  
HASAN ABU KASSIM
Keyword(s):  
Energy Loss ◽  
Neutrino Energy ◽  
Electron Neutrino ◽  
Stopping Power ◽  
Power Equation ◽  
Electron Positron ◽  
Extra Energy ◽  
Expansion Of The Universe ◽  
Current Interaction ◽  
The Universe

Neutrinos are produced copiously in the early universe. Neutrinos and antineutrinos ceased to be in equilibrium with radiation when the weak interaction rate becomes slower than the rate expansion of the universe. The ratio of the temperature of the photon to the temperature of the neutrino at this stage is Tγ/Tν = (11/4)1/3. We investigate the neutrino energy loss due to the oscillation of the electron neutrino into a different flavor in the charged-current interaction of νe-e- based on the work of Sulaksono and Simanjuntak. The energy loss from the neutrinos ΔEν during the decoupling of the neutrinos with the rest of the matter would be a gain in the energy of the electrons and can be obtained from the integration of stopping power equation ΔEν = (dEν/dT-1)dT-1 where Eν and T are the energy of the neutrinos and the temperature respectively. When the universe expands and matter-radiation decouples, an extra energy will be transferred to the photons via the annihilation of the electron-positron pairs, e++e-→γ+γ. This consequently will increase the temperature of the photons. The net effect to the lowest order is an increase in the ratio of the photon temperature to the neutrino temperature. The magnitude of energy loss of the neutrino is ∼10-4-10-5 MeV for the probability of conversion of νe → νi (i = μ,τ) between 0 to 1.0.

scholarly journals Enhanced energy loss of heavy ions passing a fully ionized hydrogen plasma

1996 ◽  
Vol 14 (4) ◽  
pp. 599-604 ◽  
Author(s):  
R. Kowalewicz ◽  
E. Boggasch ◽  
D.H.H. Hoffmann ◽  
J. Jacoby ◽  
W. Laux ◽  
...  
Keyword(s):  
Energy Loss ◽  
Heavy Ions ◽  
Electrical Discharge ◽  
Hydrogen Plasma ◽  
Hydrogen Gas ◽  
Low Energy ◽  
Stopping Power ◽  
Electron Densities ◽  
Singly Charged

Experiments are presented that demonstrate the high stopping power of fully ionized hydrogen plasma for low-energy heavy ions. A plasma with electron densities up to 7.1016 cm–3 at temperatures above 1 eV was created by an electrical discharge. In the described experiment, a stopping power of 1.08 GeV/(mg/cm2) was measured using singly charged krypton ions at 45–keV/u energy. The measured stopping power exceeds the corresponding value in cold hydrogen gas by a factor of 35. These measurements confirm the theoretical stopping power predictions close to the expected maximum in a fully ionized plasma.

scholarly journals Measurement of stopping power of 240 MeV argon ions in partially ionized helium discharge plasma

2000 ◽  
Vol 18 (4) ◽  
pp. 647-653 ◽  
Author(s):  
M. OGAWA ◽  
U. NEUNER ◽  
H. KOBAYASHI ◽  
Y. NAKAJIMA ◽  
K. NISHIGORI ◽  
...  
Keyword(s):  
Energy Loss ◽  
Electron Density ◽  
Target Thickness ◽  
Stopping Power ◽  
Helium Plasma ◽  
Discharge Ignition ◽  
The Mean ◽  
Argon Ions ◽  
Partially Ionized ◽  
Mean Charge

An energy loss of 240 MeV argon ions in a Z-pinch helium plasma has been for the first time observed throughout the entire pinching process. Standard Stark broadening analysis gives an electron density ranging from 4 to 6 × 1017 cm−3 during the pinch. To deduce stopping power from the energy loss, the target thickness of the helium plasma has been evaluated assuming the mean charge of helium based on thermal equilibrium. The observed electron density and the mean charge of helium give a target thickness of 30 ± 3 μg cm−2 from 1 μs to 1.8 μs after the discharge ignition. The measured stopping power exceeds a tabulated value for cold helium gas by a factor of 2 to 3 around the time of the first pinch. The experimental stopping power is compared with theoretical values calculated using an equation of stopping power for a partially ionized plasma.

Energy loss effective charge for slow ions in electron gas

Vacuum ◽  
2003 ◽  
Vol 70 (2-3) ◽  
pp. 359-364
Author(s):  
Marek Moneta ◽  
Jerzy Czerbniak
Keyword(s):  
Energy Loss ◽  
Effective Charge ◽  
Electron Gas ◽  
Slow Ions

Electronic Stopping Power for Low Energy Ions

1985 ◽  
Vol 45 ◽  
Author(s):  
N. Azziz ◽  
K. W. Brannon ◽  
G. R. Srinivasan
Keyword(s):  
Effective Charge ◽  
Density Functional ◽  
Considerable Effect ◽  
Low Energy ◽  
Stopping Power ◽  
Target Electron ◽  
Functional Formalism ◽  
Low Energy Ions ◽  
Electronic Stopping Power

ABSTRACTA procedure to be used in ion implantation calculations has been developed to determine the stopping power of an ion at low energy as a function of its effective charge. The ion effective charge accounts for screening of the ion and has been found to have considerable effect on the stopping power through its dependence on the target electron density. Steps in the procedure include: the calculation of the Fermi momentum of the target, calculation of the relative velocity between the projectile and target electron cloud, determination of the screening distance for the ion, and calculation of the proton stopping power Sp according to the density-functional formalism. The ion stopping power is then is the ion effective charge. The procedure can be applied to semiconductors and metals. Comparisons are reported with the predictions of the Firsov and Lindhard methods which do not include any effective charge or shell structure considerations. The computer program MARLOWE has been modified to include this method for calculating the stopping power. Results in the form of implanted boron profiles in silicon will be presented.

Evolution of the shape of fission fragment energy spectrum with absorber thickness in two different media and effective charge correction

2022 ◽  
Author(s):  
Rajkumar Santra ◽  
V. G. Vamaravalli ◽  
Ankur Roy ◽  
Balaram Dey ◽  
Subinit Roy
Keyword(s):  
Energy Spectrum ◽  
Energy Loss ◽  
Effective Charge ◽  
Correction Term ◽  
Stopping Power ◽  
Absorber Thickness ◽  
Shape Parameters ◽  
Bohr Theory ◽  
Present Simulation ◽  
Charge Formula

The energy loss behavior of fission fragments (FFs) from [Formula: see text]Cf(sf) in thin Mylar [Formula: see text] and Aluminium absorber foils has been revisited. The aim is to investigate the observed change in the well-known asymmetric energy of spontaneous fission of [Formula: see text]Cf as the fragments pass through increasingly thick absorber foils. Two different types of absorbers have been used: one elemental and the other an organic compound. The stopping powers have been determined as a function of energy for three fragment mass groups with average masses having [Formula: see text], 141.8, 125.8 corresponding to light, heavy and symmetric fragments of [Formula: see text]Cf. The energy loss data have been compared with the predictions of SRIM 2013 code. The best representations of the data have been achieved using the effective Z correction term in the stopping power relation from the classical Bohr theory. Using the effective charge ([Formula: see text]) in the stopping power relation in the classical Bohr theory best describes the stopping power data. Spectrum shape parameters, subsequently, have been extracted from the energy spectra of FFs for different foil thicknesses. The effective charge ([Formula: see text]) correction term determined from the stopping power data is then used in the simulation for the absorber thickness dependence of the shape parameters of the energy spectrum. The present simulation results are compared with the TRIM prediction. The trends of the absorber thickness dependence of the spectrum shape parameters, for both Mylar and Aluminium, are well reproduced with the present simulation.

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