Effective charges of ions and the stopping power of dense media

Brandt, Werner

doi:10.1016/0029-554x(82)90482-7

Cited by 92 publications

(22 citation statements)

References 24 publications

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“…was obtained by removing the nuclear stopping power component from their experimental measurements. The analytical model by Heredia-Avalos and co-workers [48] employs the dielectric response formulation using a Mermin-type dielectric function [49] together with a modified Brandt-Kitagawa model [50,51] for the effective charge state of the proton. The dielectric function was obtained by fitting to the experimental spectrum of the energy loss function in the optical limit (q = 0).…”

Section: Resultsmentioning

confidence: 99%

“…In addition to this mass-density effect, the velocity dependence of the charge state has also been widely studied, and various theoretical descriptions exist in the literature. The commonly used Brandt-Kitagawa theory [50,51], for example, models the charge state as a function of the scaled velocity based on the Thomas-Fermi model. Clearly, an important aspect in applying the linear response theory formalism for calculating stopping power is the question of whether the use of an effective charge for the swift ion can better represents the electronic stopping power curve.…”

Section: Hementioning

confidence: 99%

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Electronic stopping for protons andαparticles from first-principles electron dynamics: The case of silicon carbide

Yost

Kanai

2016

Phys. Rev. B

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We present the first-principles determination of electronic stopping power for protons and α-particles in a semiconductor material of great technological interest: silicon carbide. The calculations are based on non-equilibrium simulations of the electronic response to swift ions using real-time time-dependent density functional theory (RT-TDDFT). We compare the results from this first-principles approach to those of the widely used linear response formalism and determine the ion velocity regime within which linear response treatments are appropriate. We also use the non-equilibrium electron densities in our simulations to quantitatively address the long-standing question of the velocity-dependent effective charge state of projectile ions in a material, due to its importance in linear response theory. We further examine the validity of the recently proposed centroid path approximation recently proposed for reducing the computational cost of acquiring stopping power curves from RT-TDDFT simulations.

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Section: Resultsmentioning

confidence: 99%

Section: Hementioning

confidence: 99%

Electronic stopping for protons andαparticles from first-principles electron dynamics: The case of silicon carbide

Yost

Kanai

2016

Phys. Rev. B

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“…[6][7][8][9][10][11][12] If a SHI with energy E enters a target and its initial charge q init is lower than the mean equilibrium one in the target bulk ͗q͘ ͑can be calculated, e.g., using formulas given in Ref. [6][7][8][9][10][11][12] If a SHI with energy E enters a target and its initial charge q init is lower than the mean equilibrium one in the target bulk ͗q͘ ͑can be calculated, e.g., using formulas given in Ref.…”

Section: Introductionmentioning

confidence: 99%

Charge state effect on near-surface damage formation in swift heavy ion irradiated InP

Kamarou

Wendler

Wesch

2005

Journal of Applied Physics

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“…The summation is performed over all the possible charge states q of the projectile, characterized by the Fourier transform ρ q (k) of its electronic density, which is described by the Brandt-Kitagawa model [57,58]. φ q are the equilibrium charge state fractions of the projectile, which depend on its energy and the target nature; we have used in this work a parametrization to experimental data [59].…”

Section: Theoretical Energy Loss Calculationsmentioning

confidence: 99%

Energy deposition of H and He ion beams in hydroxyapatite films: A study with implications for ion-beam cancer therapy

et al. 2014

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Ion-beam cancer therapy is a promising technique to treat deep-seated tumors; however, for an accurate treatment planning, the energy deposition by the ions must be well known both in soft and hard human tissues. Although the energy loss of ions in water and other organic and biological materials is fairly well known, scarce information is available for the hard tissues (i.e., bone), for which the current stopping power information relies on the application of simple additivity rules to atomic data. Especially, more knowledge is needed for the main constituent of human bone, calcium hydroxyapatite (HAp), which constitutes 58% of its mass composition. In this work the energy loss of H and He ion beams in HAp films has been obtained experimentally. The experiments have been performed using the Rutherford backscattering technique in an energy range of 450-2000 keV for H and 400-5000 keV for He ions. These measurements are used as a benchmark for theoretical calculations (stopping power and mean excitation energy) based on the dielectric formalism together with the MELF-GOS (Mermin energy loss function-generalized oscillator strength) method to describe the electronic excitation spectrum of HAp. The stopping power calculations are in good agreement with the experiments. Even though these experimental data are obtained for low projectile energies compared with the ones used in hadron therapy, they validate the mean excitation energy obtained theoretically, which is the fundamental quantity to accurately assess energy deposition and depth-dose curves of ion beams at clinically relevant high energies. The effect of the mean excitation energy choice on the depth-dose profile is discussed on the basis of detailed simulations. Finally, implications of the present work on the energy loss of charged particles in human cortical bone are remarked.

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Effective charges of ions and the stopping power of dense media

Cited by 92 publications

References 24 publications

Electronic stopping for protons andαparticles from first-principles electron dynamics: The case of silicon carbide

Electronic stopping for protons andαparticles from first-principles electron dynamics: The case of silicon carbide

Charge state effect on near-surface damage formation in swift heavy ion irradiated InP

Energy deposition of H and He ion beams in hydroxyapatite films: A study with implications for ion-beam cancer therapy

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