Measurement of the symmetric charge-exchange cross section in helium and argon in the impact energy range 1-10 keV

Hegerberg, R; Stefánsson, Þórarinn; Elford, M. T.

doi:10.1088/0022-3700/11/1/017

Cited by 47 publications

(23 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, the absolute cross section information of these inelastic processes are of interest, in particular the energy dependence of collisions of K + ions with He atoms because the excitation probabilities in these collisions (with some exceptions) are one or two orders of magnitude smaller than in symmetric and quasisymmetric systems [11][12][13][14]. Another remarkable feature of inelastic collisions of these closed-shell particles is that the excitation into a doubly excited state occurs with a high probability.…”

Section: Introductionmentioning

confidence: 99%

“…In order to discuss quantitatively the excitation mechanism one has to evaluate the parameters of existing theories and explore the contributions of separate inelastic channels for the investigated processes by using experimental measurements. Despite many studies of K + -He collisions which have been carried out by various methods [11,[13][14][15][16][17][18][19][20][21], available data for the absolute cross sections of the above-mentioned processes are contradictory [11,16,17,20] and, in some cases, unreliable [15].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Inelastic processes in K+-He collisions in energy range 0.7–10 keV

et al. 2013

View full text Add to dashboard Cite

Absolute cross sections for charge exchange, ionization, stripping, and excitation in K + -He collisions were measured in the ion energy range 0.7-10 keV. The experimental data and the schematic correlation diagrams are used to analyze and determine the mechanisms for these processes. The increase of the excitation probability of inelastic channels with the angle of scattering is revealed. An exceptionally highly excited state of He is observed and a peculiarity for the excitation function of the resonance line is explained. The intensity ratio for the excitation of the K II λ = 60.1 nm and λ = 61.2 nm lines is 5:1, which indicates the high probability for excitation of the singlet resonance level 1 P 1 compared to the triplet level 3 P 1 . The similarity of the population of the 4p state of the potassium ion and atom as well as the anomalously small values of the excitation cross sections are explained.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Inelastic processes in K+-He collisions in energy range 0.7–10 keV

et al. 2013

View full text Add to dashboard Cite

show abstract

“…The cross section of such a mechanism has been estimated for helium by many authors to 10 À15 cm 2 at low kinetic energy [32][33][34][35]. k IMFP , k EMFP have been evaluated and are given in Table 2.…”

Section: Tablementioning

confidence: 99%

Low flux and low energy helium ion implantation into tungsten using a dedicated plasma source

Pentecoste

Thomann

Melhem

et al. 2016

Nuclear Instruments and Methods in Physics Research Section B:

View full text Add to dashboard Cite

a b s t r a c tThe aim of this work is to investigate the first stages of defect formation in tungsten (W) due to the accumulation of helium (He) atoms inside the crystal lattice. To reach the required implantation conditions, i.e. low He ion fluxes (10 11 -10 14 ions.cm 2 .s À1 ) and kinetic energies below the W atom displacement threshold (about 500 eV for He + ), an ICP source has been designed and connected to a diffusion chamber. Implantation conditions have been characterized by means of complementary diagnostics modified for measurements in this very low density helium plasma. It was shown that lowest ion fluxes could only be reached for the discharge working in capacitive mode either in a or c regime. Special attention was paid to control the energy gained by the ions by acceleration through the sheath at the direct current biased substrate. At very low helium pressure, in a regime, a broad ion energy distribution function was evidenced, whereas a peak centered on the potential difference between the plasma and the biased substrate was found at higher pressures in the c mode. Polycrystalline tungsten samples were exposed to the helium plasma in both regimes of the discharge and characterized by positron annihilation spectroscopy in order to detect the formed vacancy defects. It was found that W vacancies are able to be formed just by helium accumulation and that the same final implanted state is reached, whatever the operating mode of the capacitive discharge.

show abstract

“…At moderate energies, collisions of closed-shell ions with closed-shell atoms for various inelastic channels such as the ionization, charge-exchange, stripping, and excitation are well understood. However, the absolute cross section information of these inelastic processes are of interest -in particular, the energy dependence of collisions of K + ions with He atoms because the excitation probabilities in these collisions (with some exceptions) are one or two orders of magnitude smaller than in symmetric and quasisymmetric systems [11][12][13][14]. Another remarkable feature of inelastic collisions of these closed-shell particles is that the excitation into a doubly excited state occurs with a high probability.…”

Section: Introductionmentioning

confidence: 99%

Inelastic processes in K^(+)- He collisions in energy range 0.7 - 10 keV

Lomsadze,

Gochitashvili,

Kezerashvili

et al. 2013

Preprint

View full text Add to dashboard Cite

Absolute cross sections for charge exchange, ionization, stripping and excitation in K + −He collisions were measured in the ion energy range 0.7 − 10 keV. The experimental data and the schematic correlation diagrams are used to analyze and determine the mechanisms for these processes. The increase of the excitation probability of inelastic channels with the angle of scattering is revealed. An exceptionally highly excited state of He is observed and a peculiarity for the excitation function of the resonance line is explained. The intensity ratio for the excitation of the K II λ = 60.1 nm and λ = 61.2 nm lines is 5:1 which indicates the high probability for excitation of the singlet resonance level 1 P1 compared to the triplet level 3 P1. The similarity of the population of the 4p state of the potassium ion and atom as well as the anomalously small values of the excitation cross sections are explained.

show abstract

Measurement of the symmetric charge-exchange cross section in helium and argon in the impact energy range 1-10 keV

Cited by 47 publications

References 24 publications

Inelastic processes in K+-He collisions in energy range 0.7–10 keV

Inelastic processes in K+-He collisions in energy range 0.7–10 keV

Low flux and low energy helium ion implantation into tungsten using a dedicated plasma source

Inelastic processes in K^(+)- He collisions in energy range 0.7 - 10 keV

Contact Info

Product

Resources

About