Electron ionization and excitation coefficients for argon, krypton, and xenon in the low <i>E</i>/<i>N</i> region

Specht, L. T.; Lawton, S. A.; DeTemple, T. A.

doi:10.1063/1.327395

Cited by 55 publications

(34 citation statements)

References 16 publications

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“…This can be seen in low pressure measurements for Ar and CO 2 . Our measurements for Ar agree well with the references from Kruithof [24] and Specht [25] over the whole measured range. For CO 2 our measurements are between those of Bhalla [26] and Yousfi [27], the spread in the values of reported ionization rate is quite significant in [27].…”

Section: Benchmark Resultssupporting

confidence: 80%

“…9 the effective ionization coefficient is shown. As we provide a full set of swarm parameters, it is possible to scale our effective ionization rate constant with the corre- [24], (x) Specht [25]), for CO 2 ( (+) Bhalla [26], (x) Yousfi [27], ( ) Petri [5]) and for N 2 ( (+) Yousfi [27], (x) Haydon [28], ( ) Petri [5]) sponding drift velocity and compare it to literature where only the effective ionization coefficient is given. The drift velocity increases for most measurements around a factor of 4.…”

Section: Benchmark Resultsmentioning

confidence: 99%

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Detailed precision and accuracy analysis of swarm parameters from a pulsed Townsend experiment

Haefliger

Franck

2018

Review of Scientific Instruments

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Abstract. A newly built Pulsed Townsend experimental setup which allows to measure both electron and ion currents is presented. Based on findings operating a previous experiment and on literature, the accuracy of the experimental input parameters was identified as necessary requirement to obtain accurate swarm parameters such as the effective ionization rate coefficient, the density-reduced mobility and the density-normalized longitudinal diffusion coefficient. The influence of the input parameters (gap distance, applied voltage, measured pressure and temperature) is analyzed in detail. An overall accuracy of ±0.5% in the density reduced electric field (E/N ) is achieved, which is close to the theoretically possible limit using the chosen components. The precision of the experimental results is higher than the accuracy. Through an extensive measurement campaign, the repeatability of our measurements proved to be high and similar to the precision. The reproducibility of results at identical (E/N ) is similar to the precision for different distances but decreases for varying pressures. For benchmark purposes, measurements for Ar, CO 2 and N 2 are presented and compared with our previous experimental setup, simulations and other experimental references.PACS numbers: 00.00, 20.00, 42.10 Submitted to: Rev. Sci. Instrum. 2 Definitions (from [1] based on GUM [2]):True value:Value that would be obtained by a perfect measurement, true values are indeterminate by nature. Accuracy:Closeness of the agreement between the result of a measurement and a true value of the measurand. Error:Difference between a measurement and the true value of the measurand. Precision:Closeness of agreement between independent measurements of a quantity under the same conditions. It is a measure of how well a measurement can be made without reference to a theoretical or true value (only in [1]). For example the ionization rate is determined by a linear regression of the log(I) versus time there a random noise affecting I would affect the obtained ionization rate. I is the measured current. Repeatability:Precision of results of successive, independent measurements carried out under the same conditions. Reproducibility: Precision of results of successive independent measurements carried out under different conditions. Uncertainty:Parameter, associated with the result of a measurement, that characterizes the dispersion of the values that could reasonably be attributed to the measurand.

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Section: Benchmark Resultssupporting

confidence: 80%

Section: Benchmark Resultsmentioning

confidence: 99%

Detailed precision and accuracy analysis of swarm parameters from a pulsed Townsend experiment

Haefliger

Franck

2018

Review of Scientific Instruments

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“…The present values of the reduced ionization coefficient are shown in figure 3(c) in comparison with the data of Jelenak et al [34] and Bozin et al [35] who obtained the ionization and excitation coefficients for a wide range of the reduced electric field, 50 Td-9 kTd, via measurements of the spatial dependence of the optical emission intensity from a stationary Townsend discharge (operated in the µA regime); Specht et al [36] who deduced the ionization coefficient from the ratio of the integrated ion and electron cur rents in a pulsed drifttube apparatus, and Lakshminarasimha and Lucas [37] who obtained N / α under stationary conditions, between 8 and 1271 Td, based on the measurements of the current as a function of electrode gap in a drift tube. Our measured values (of which the accuracy we estimate to be below 6%) cover a wider range of E/N, compared to the previous studies.…”

Section: Argonmentioning

confidence: 49%

“…The results were accepted and are presented here only for those cases when the deviations between the data obtained from the fits over different z domains were within ±3% for W, ±5% for D L and ν (±10% for synthetic air, due to the worse signal to noise ratio, see later). [31], Nakamura [32], Hernández-Ávila et al [33], Jelenak et al [34], Bozin et al [35], Specht et al [36], Lakshminarasimha and Lucas [37]. Panel (a) [25] reprinted with permission AIP Publishing LLC.…”

Section: Experimental Apparatus and Data Evaluationmentioning

confidence: 99%

Scanning drift tube measurements of electron transport parameters in different gases: argon, synthetic air, methane and deuterium

Korolov¹,

Vass²

2016

J. Phys. D: Appl. Phys.

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Measurements of transport coefficients of electrons in a scanning drift tube apparatus are reported for different gases: argon, synthetic air, methane and deuterium. The experimental system allows the spatio-temporal development of the electron swarms ('swarm maps') to be recorded and this information, when compared with the profiles predicted by theory, makes it possible to determine the 'time-of-flight' transport coefficients: the bulk drift velocity, the longitudinal diffusion coefficient and the effective ionization coefficient, in a well-defined way. From these data, the effective Townsend ionization coefficient is determined as well. The swarm maps provide, additionally, direct, unambiguous information about the hydrodynamic/ non-hydrodynamic regimes of the swarms, aiding the selection of the proper regions applicable for the determination of the transport coefficients.

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“…However the most important recent development has been the introduction of Ar-N 2 lasers [8][9][10][11][12]. The precise knowledge of the rate coefficients for different inelastic collision processes which take place in such lasers is of great importance for understanding their kinetics [13][14]. There are many data for excitation transfer (from Ar m to N2) [15][16], , quenching of metastable states [17][18], charge transfer [19][20][21] and other important processes [22-243. However for some reactions the knowledge is far * and Faculty of Natural Sciences, Beograd, Yugoslavia ** Present address: Elect.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of excitation of argon metastables by an electron swarm in argon nitrogen gas mixtures

1983

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Excitation of argon metastable levels (43P2 +43Po) in a nonselfsustained discharge in Ar(>99%)+N2(<__l%) gas mixtures has been investigated by measuring N 2 second positive group which is the result of excitation transfer from Ar metastables to N 2 molecules. The method is based on the assumption, experimentally verified, that addition of small quantities of N 2 do not change markedly the probability of Ar excitation. The obtained excitation coefficients for production of Ar m in the E/N range (20-70) x 10 21 Vm 2 are (3.5-13) x 10 22 m 2 with an estimated uncertainty of -t-50 %. Simultaneously, excitation coefficients for direct excitation of nitrogen C-state by swarm electrons in Ar-N 2 mixtures have been obtained. A comparison of nitrogen spectra excited by electrons and by argon metastables showed significant differences in relative population of vibrational and rotational levels of the N2(CaH,) state in these two cases.

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Electron ionization and excitation coefficients for argon, krypton, and xenon in the low E/N region

Cited by 55 publications

References 16 publications

Detailed precision and accuracy analysis of swarm parameters from a pulsed Townsend experiment

Detailed precision and accuracy analysis of swarm parameters from a pulsed Townsend experiment

Scanning drift tube measurements of electron transport parameters in different gases: argon, synthetic air, methane and deuterium

Experimental investigation of excitation of argon metastables by an electron swarm in argon nitrogen gas mixtures

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