Studies of xenon ECR plasma: search for a better understanding of the gas-mixing and anomalous effects

Kumar, Pravin; Mal, Kedar; Kanjilal, D.

doi:10.1088/0963-0252/23/6/065007

Cited by 6 publications

(7 citation statements)

References 20 publications

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“…The observed trends in the intensities of Kr isotopes may be due to the nonlinear effects (induced ion sound wave scattering on ions), which take the smallness of the relative mass difference (ΔA/A) into account to model the heating mechanism of the ions having different charge to mass ratios [23,24] in two-component plasmas. The comparison of the present results with previously studied Xe plasma [21] , which showed complete absence of the isotope anomaly, further indicates that the relative mass difference plays some role to yield final ion intensities in the plasma. However, validating the nonlinear Landau damping model would require more experiments by varying the mixing ratios and simplifying the experimental procedure to two-component plasma without oxygen mixing.…”

Section: Resultssupporting

confidence: 83%

“…The observed trends in the isotope anomaly do not follow the prediction of linear Landau damping. In comparison with the previous study of the xenon plasma , the influence of the relative mass difference on the isotopic anomaly is also seen in the present experiment. The present experiment performed with powerful ECR ion sources, which produce high intensities of highly charged ions, will certainly be very useful to shed more light on the isotope anomaly in ECR plasmas.…”

Section: Resultsmentioning

confidence: 99%

“…The 90 0 beam line of the new LEIBF was used for analysing the isotopic intensities. The extraction, pre and post analysis systems of the new LEIBF are described elsewhere . A high power Faraday cup installed in 90 0 beam line was used to measure the ion intensities.…”

Section: Methodsmentioning

confidence: 99%

“…The isotope anomaly has been studied so far only in the ECR plasmas produced by the dissociation of the molecular gases (O 2 , CO 2 and N 2 ) and the ionization of the released atomic species, which are chemically reactive with the metallic wall of the ion source. To decouple the effects arising from the plasma surface interactions, the charge state distribution of chemically inert Xe ECR plasma has been studied in a very recent experiment . The isotope anomaly was completely missing in the pure and the oxygen‐mixed xenon plasmas because of the quite closer natural abundances of 129 Xe, 131 Xe and 132 Xe isotopes (~26%, 21% and 27%, respectively) and a very low relative mass difference in the isotopes.…”

Section: Introductionmentioning

confidence: 99%

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Charge state distribution studies of pure and oxygen mixed krypton ECR plasma – signature of isotope anomaly and gas mixing effect

2016

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We report the charge state distributions of the pure, 25% and 50% oxygen mixed krypton plasma to shed more light on the understanding of the gas mixing and the isotope anomaly [A. G. Drentje, Rev. Sci. Instrum. 63 (1992) 2875 and Y Kawai, D Meyer, A Nadzeyka, U Wolters and K Wiesemann, Plasma Sources Sci. Technol. 10 (2001) 451] in the electron cyclotron resonance (ECR) plasmas. The krypton plasma was produced using a 10 GHz all-permanent-magnet ECR ion source. The intensities of the highly abundant four isotopes, viz. Kr (~11.58%), Kr (~11.49%), Kr (~57%) and Kr (17.3%) up to ~ +14 charge state have been measured by extracting the ions from the plasma and analysing them in the mass and the energy using a large acceptance analyzer-cum-switching dipole magnet. The influence of the oxygen gas mixing on the isotopic krypton ion intensities is clearly evidenced beyond +9 charge state. With and without oxygen mixing, the charge state distribution of the krypton ECR plasma shows the isotope anomaly with unusual trends. The anomaly in the intensities of the isotopes having quite closer natural abundance, viz. Kr, Kr and Kr, Kr is prominent, whereas the intensity ratio of Kr to Kr shows a weak signature of it. The isotope anomaly tends to disappear with increasing oxygen mixing in the plasma. The observed trends in the intensities of the krypton isotopes do not follow the prediction of linear Landau wave damping in the plasma. Copyright © 2016 John Wiley & Sons, Ltd.

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Section: Resultssupporting

confidence: 83%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Charge state distribution studies of pure and oxygen mixed krypton ECR plasma – signature of isotope anomaly and gas mixing effect

2016

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“…A set of pristine indium oxide films was implanted with 25‐keV N + ions at three different fluences (viz. 1.0 × 10 15 , 5.0 × 10 15 and 1.0 × 10 16 ions/cm 2 ) using electron cyclotron resonance (ECR) ion sourced‐based low energy ion beam facility (LEIBF) . Another set of the pristine films was implanted with 25‐keV Co − ions also at the same fluences using the source of negative ions by Cs sputtering (SNICS).…”

Section: Methodsmentioning

confidence: 95%

Ion induced controlled modifications in structural and optical properties of indium oxide thin films – studies with 25‐keV Co⁻ and N⁺ beam implantations

Sethi

Kaushik

Aziz

et al. 2017

Surface & Interface Analysis

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Two sets of indium oxide thin films (~150 nm) grown on quartz substrates using thermal evaporation technique were processed separately with 25-keV Co À and N + ions with several fluences ranging from 1.0 × 10 15 to 1.0 × 10 16 ions/cm 2 . The pristine and the ion implanted films were characterized by Rutherford backscattering spectroscopy (RBS), X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and UV-Vis spectrometry. The RBS spectra reveal signature of only cobalt and nitrogen in accordance to their fluences confirming absence of any contamination arising due to ion implantation. An increase in the average crystallite size (from 13.7 to 15.3 nm) of Co À ions implanted films was confirmed by XRD. On the other hand, the films implanted with N + ions showed a decrease in the average crystallite size from 20.1 to 13.7 nm. The XRD results were further verified by SEM micrographs. As seen in AFM images, the RMS surface roughness of the samples processed by both ion beams was found to decrease a bit (29.4 to 22.2 nm in Co À implanted samples and 24.2 to 23.3 nm in N + implanted samples) with increasing fluence. The Tauc's plot deduced from UV-visible spectroscopy showed that the band gap decreases from 3.54 to 3.27 eV in Co À implanted films and increases from 3.38 to 3.58 eV for films implanted with N + ions. The experimental results suggest that the modifications in structural and optical properties of indium oxide films can be controlled by optimizing the implantation conditions.

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Studies of pure and nitrogen gas mixed xenon ECR plasma: Signature of abundance dependent unusual trends in isotope anomaly

2022

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We report the effect of N 2 gas-mixing in the xenon electron cyclotron resonance (ECR) plasma, and abundance-dependent novel, exciting and unusual trends of the isotope anomaly. The xenon plasma was produced using a 10 GHz all-permanentmagnet NANOGAN ECR ion source, and the charge state distributions of naturally abundant six stable xenon isotopes with and without N 2 gas-mixing (at 25%, 50%, and 75%) were recorded. The intensity ratio of the heavier to lighter isotope, where the heavier isotope is less abundant, showed a clear signature of the isotope anomaly as explained by the linear Landau wave damping theory. Contrary to the theoretical prediction that the isotope anomaly should vanish with a relatively large fraction of the heavier isotope in mixed plasmas, the trends of intensity ratios observed in such cases are very unusual and have almost the mirror-symmetrical shapes of those trends recorded with less abundant heavier isotope. Further, the effect of relative mass difference on the isotope anomaly was also evidenced. The N 2 gas-mixing of the xenon plasma at 25% and 50% shifted the entire charge state distribution toward the higher intensity side owing to the supply of additional electrons that caused high ionization efficiency. However, a prominent gas-mixing effect was observed at 75% of N 2 mixing in the xenon plasma beyond the +7 charge state. The abundancedependent unusual trends in isotope anomaly have been explained by considering different ionic temperatures, ion heating by the wave damping, and Coulomb scattering in the core of the plasma.charge state distribution, electron cyclotron resonance (ECR) plasma, gas mixing effect, isotope anomaly, low energy accelerator, mass analyzer | INTRODUCTIONThe capability of producing multiply charged positive ions via the electron-impact ionization without using any cathode/filament made the electron cyclotron resonance ion sources (ECRIS) very popular among the accelerator physicists. [1][2][3][4][5][6][7] The intensities in ECRIS are mainly governed by the ion-confinement using the magnetic fields. In a typical structure, multipole permanent magnets are used for the radial confinement of the ions, whereas the axial confinement of the ions is achieved either by the permanent magnets or the electromagnets. 8,9 The fourth generation high-frequency ECRIS utilized superconducting magnetic coils for the axial confinement of the ions. [10][11][12] The resonant electrons, which have a gyration frequency equals to the frequency of the input electromagnetic wave, gain enough kinetic energy to ionize the gaseous atom/molecules and yield intense plasma. 13

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Studies of xenon ECR plasma: search for a better understanding of the gas-mixing and anomalous effects

Cited by 6 publications

References 20 publications

Charge state distribution studies of pure and oxygen mixed krypton ECR plasma – signature of isotope anomaly and gas mixing effect

Charge state distribution studies of pure and oxygen mixed krypton ECR plasma – signature of isotope anomaly and gas mixing effect

Ion induced controlled modifications in structural and optical properties of indium oxide thin films – studies with 25‐keV Co⁻ and N⁺ beam implantations

Studies of pure and nitrogen gas mixed xenon ECR plasma: Signature of abundance dependent unusual trends in isotope anomaly

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Studies of xenon ECR plasma: search for a better understanding of the gas-mixing and anomalous effects

Cited by 6 publications

References 20 publications

Charge state distribution studies of pure and oxygen mixed krypton ECR plasma – signature of isotope anomaly and gas mixing effect

Charge state distribution studies of pure and oxygen mixed krypton ECR plasma – signature of isotope anomaly and gas mixing effect

Ion induced controlled modifications in structural and optical properties of indium oxide thin films – studies with 25‐keV Co− and N+ beam implantations

Studies of pure and nitrogen gas mixed xenon ECR plasma: Signature of abundance dependent unusual trends in isotope anomaly

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Ion induced controlled modifications in structural and optical properties of indium oxide thin films – studies with 25‐keV Co⁻ and N⁺ beam implantations