Atomic nitrogen density measurements by actinometry method in the toroidal device NAGDIS-T

Kajita, Shin; Asaoka, Koji; Tanaka, Hirohiko; Nishio, Ryosuke; Tsutsumi, Takayoshi; Hori, Masaru; Ohno, Noriyasu

doi:10.35848/1347-4065/aba456

Cited by 3 publications

(5 citation statements)

References 37 publications

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“…At p n = 4.74 mTorr and I d = 10 A, n N reached 6.2 × 10 17 m −3 . The actinometry resulted in nearly consistent values with the VUVAS and it decreases with p n [6].…”

mentioning

confidence: 56%

“…In previous studies using the NAGDIS-T, n N in the ground state was measured spectroscopically by assuming coronal equilibrium [5] and by actinometry [6]. As a result, it was confirmed that n N was on the order of 10 17 m −3 .…”

mentioning

confidence: 67%

“…In Ref. [6], VUVAS was used to compare with actinometry under limited experimental conditions; the present study extends the conditions to higher neutral pressure, p n , and higher discharge current, I d , to generate a highern N .…”

mentioning

confidence: 94%

“…For actinometry, 1% Ar is introduced into the nitrogen plasma, and an N emission line at λ = 746.8 nm and an Ar emission line at λ = 750.4 nm are measured. Then, n N is calculated from the ratio of the line emission intensities [6].…”

mentioning

confidence: 99%

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Nitrogen Atom Density Measurements in NAGDIS-T Using Vacuum Ultraviolet Absorption Spectroscopy

Nishio

Kajita

Tanaka

et al. 2022

Plasma and Fusion Research

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For the development of a high nitrogen atom density source, we produced nitrogen plasmas and measured the nitrogen atom density using vacuum ultraviolet absorption spectroscopy (VUVAS) at high neutral gas pressure (>1.5 mTorr) and discharge power (>500 W) in the NAGDIS-T, which could generate spiral-shaped dissociative recombining plasmas. It was seen that the nitrogen atom density increases with increasing neutral gas pressure and discharge power, and it reached 6.2 × 10 17 m −3 . In the low gas pressure case, the estimated atom density was confirmed to be consistent with that measured by the actinometry method.

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“…At p n = 4.74 mTorr and I d = 10 A, n N reached 6.2 × 10 17 m −3 . The actinometry resulted in nearly consistent values with the VUVAS and it decreases with p n [6].…”

mentioning

confidence: 56%

mentioning

confidence: 67%

mentioning

confidence: 94%

mentioning

confidence: 99%

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Nitrogen Atom Density Measurements in NAGDIS-T Using Vacuum Ultraviolet Absorption Spectroscopy

Nishio

Kajita

Tanaka

et al. 2022

Plasma and Fusion Research

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“…The density can then be determined because it is proportional to the ratio of the above lines, due to the population of the excited states being assumed to have been excited from the ground state. Some studies used this traditional actinometry method to obtain the densities of N, O, and F atoms [22][23][24][25][26]. However, the assumption that excitation from the ground state dominates the population of the measured states is incorrect in some operating conditions.…”

Section: Introductionmentioning

confidence: 99%

A novel state-resolved actinometry method to determine the nitrogen atom number density in the ground state and intra-shell excited states in low-pressure electron cyclotron resonance plasmas

Zhu,

Wang,

Wang

et al. 2024

Plasma Sources Sci. Technol.

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The active-particle number density is a key parameter for plasma material processing, space propulsion, and plasma-assisted combustion.The traditional actinometry method focuses on measuring the density of the atoms in the ground state, but there is a lack of an effective optical emission spectroscopy method to measure intra-shell excited-state densities. The latter atoms have chemical selectivity and higher energy, and they can easily change the material morphology as well as the ionization and combustion paths. In this work, we present a novel state-resolved actinometry (SRA) method, supported by a krypton line-ratio method for the electron temperature and density, to measure the number densities of nitrogen atoms in the ground and intra-shell excited states. The SRA method is based on a collisional-radiative model, considering the kinetics of atomic nitrogen and krypton including their excited states. The densities measured by our method are compared with those obtained from a dissociative model in a miniature electron cyclotron resonance plasma (ECR) source. Furthermore, the saturation effect, in which the electron density remains constant due to the microwave propagation in an ECR plasma once the power reaches a certain value, is used to verify the electron density measured by the line-ratio method. An ionization balance model is also presented to examine the measured electron temperature. All the values obtained with the different methods are in good agreement with each other, and hence a set of verified rate coefficient data used in our method can be provided. A novel concept, the "excited-state system", is presented to quickly build an optical diagnostic method based on the analysis of quantum number propensity and selection rules.

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Effect of plasma-species to functionalize isocyanate-groups on multiwalled carbon nanotubes

Ogawa

Abdel‐Fattah

Nakamura

2021

Journal of Vacuum Science &Amp; Technology B

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This article reports our recent investigation of the relationship between the density of the active species in nitrogen-oxygen plasma and the degree of isocyanate (R-NCO) functionalization onto multiwalled carbon nanotubes. We first monitored the plasma active species with optical emission spectroscopy focusing on atomic nitrogen and oxygen species, which are the major components to form NCO groups. The optical emission intensity allowed us to find the density of atomic nitrogen and oxygen in plasma through the plasma optical actinometry method. The actinometry result showed that the density of atomic nitrogen and oxygen becomes as close as the nitrogen content in plasma increased to 90%. We then investigated the functionalization ratio with the fluorescent method and Raman spectroscopy to monitor the degree of NCO functionalization. The results suggested that NCO groups on carbon nanotubes should increase as the content ratio of atomic nitrogen and oxygen becomes equal in the plasma.

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Atomic nitrogen density measurements by actinometry method in the toroidal device NAGDIS-T

Cited by 3 publications

References 37 publications

Nitrogen Atom Density Measurements in NAGDIS-T Using Vacuum Ultraviolet Absorption Spectroscopy

Nitrogen Atom Density Measurements in NAGDIS-T Using Vacuum Ultraviolet Absorption Spectroscopy

A novel state-resolved actinometry method to determine the nitrogen atom number density in the ground state and intra-shell excited states in low-pressure electron cyclotron resonance plasmas

Effect of plasma-species to functionalize isocyanate-groups on multiwalled carbon nanotubes

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