Electron swarm parameters in oxygen and methane

Al-Amin, S A J; Kucukarpaci, H N; Lucas, J.

doi:10.1088/0022-3727/18/9/009

Cited by 35 publications

(18 citation statements)

References 51 publications

(34 reference statements)

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“…The calculated diffusion coefficients (drift velocity and transversal diffusion over the mobility ratio) agree with swarm experiments [29,[55][56][57][58][59][60] within 10% in the whole 0.01-10 Td range of reduced-electric field, see Figure 4. However, it was shown already in the past that in the case of methane Boltzmann's multi-term [61,62] or Monte Carlo [63] methods are needed.…”

Section: Integral Cross Sectionssupporting

confidence: 79%

“…Experimental swarm parameters: (a) the drift velocity and (b) the transverse diffusion coefficient, compared to solutions of two-term Boltzmann equation [38] using MERT-derived momentum transfer cross-section as the input data. The experimental results are from Schmidt [29], Hunter et al [55], Haddad [56], Al-Amin et al [57], Cochran and Forester [58], Millican and Walker [59] and Pollock [60]. To choose recommended vibrational integral CS we performed a thorough screening of theories [15,45,51,52], beam experiments [30,31] and swarm analysis [29,49,50].…”

Section: Discussionmentioning

confidence: 99%

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Ramsauer-Townsend minimum in methane — modified effective range analysis

Fedus

Karwasz

2014

Eur. Phys. J. D

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Abstract. Electron-scattering cross sections in methane are analysed in the very-low energy region. The correspondence between integral elastic, elastic differential and momentum transfer cross sections is checked via a novel approach to modified effective range theory, in order to determine the depth and position of the Ramsauer-Townsend minimum. Phase shifts of the two lowest partial waves are obtained explicitly and parameterized by four coefficients with the physical meaning of the scattering lengths and the effective ranges. Using recent experiments on vibrational cross sections performed over an extended (0-180• ) angular range and comparing several theories, an agreement within 10% has been obtained between experimental total and present summed (elastic + vibrational) cross sections in the whole 0.1-2.0 eV energy range. An additional check for consistency is done using two-term Boltzmann analysis to derive electron diffusion coefficients. Calculated drift velocities and transversal diffusion coefficients at 0-10 Td reduced electric field agree within 5% with experiments.

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Section: Integral Cross Sectionssupporting

confidence: 79%

Section: Discussionmentioning

confidence: 99%

Ramsauer-Townsend minimum in methane — modified effective range analysis

Fedus

Karwasz

2014

Eur. Phys. J. D

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“…Since the drift velocity as well as the diffusion coefficient are determined from a set of measurements using different drift lengths, field uncertainties and boundary effects near the anode cancel out as does the time resolution of the detector and the initial spread of the electron 'cloud'. The probability that an electron starting at a distance z passes the totally absorbing boundary between the drift region and the proportional counter in the time interval Ct, Hdt) is given by (Chandrasekhar 1943) ( z…”

Section: Apparatus and Experimental Procedures (2a) Principle Of The Mmentioning

confidence: 99%

Drift Velocity, Longitudinal and Transverse Diffusion in Hydrocarbons derived from Distributions of Single Electrons

Schmidt¹,

Roncossek²

1992

Aust. J. Phys.

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A time of flight method is described which allows the simultaneous measurement of drift velocity w and the ratios of the longitudinal and transverse diffusion coefficients to mobility (DL/JL, DT/JL) of electrons in gases. The accuracy achieved in this omnipurpose experiment is comparable with that of specialised techniques and is estimated to be ±1 % for w and ±5% for the D / JL measurements .. Results for methane, ethane, ethene, propane, propene and cyclopropane for values of E/N (the electric field strength divided by the number density) ranging from 0·02 to 15 Td are presented and discussed (1 Td = 10-21 Vm 2 ).

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“…3 for comparison. The experimental studies in methane have been reported by investigators such as Al-Amin et al, 21 Haddad, 23 FIG. 2.…”

Section: Resultsmentioning

confidence: 89%

“…In Fig. 3, the drift velocities taken from AlAmin et al 21 and Hunter et al 22 are denoted by W because it is unclear whether their velocities are equivalent to W r or W m . As is shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Time-of-flight observation of electron swarm in methane

Hasegawa¹,

Date²,

Yoshida³

et al. 2009

Journal of Applied Physics

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This paper reports on the evolution of an isolated electron swarm, which is experimentally observed as spatial distributions at every moment. This observation is assumed to directly correspond to the conventional time-of-flight theory. We have measured the spatial distribution of electrons using a double-shutter technique in the drift tube, where a shutter electrode to collect electrons can be slid along the field ͑E / N͒ direction in order to capture a relative electron number at a certain range of location. As a typical parameter defined by this spatial distribution, the center-of-mass drift velocity ͑W r ͒ is determined for methane gas. The result is compared with the mean-arrival-time drift velocity ͑W m ͒ defined from the arriving electron number at fixed positions. We have also performed a theoretical analysis in which a Fourier transformed Boltzmann equation is solved to deduce both of the drift velocities from a dispersion relationship. The difference between W r and W m at high E / Ns ͑above 200 Td͒ is clearly ascertained in the experimental and theoretical investigations, which is attributable to the occurrence of ionization events.

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Electron swarm parameters in oxygen and methane

Cited by 35 publications

References 51 publications

Ramsauer-Townsend minimum in methane — modified effective range analysis

Ramsauer-Townsend minimum in methane — modified effective range analysis

Drift Velocity, Longitudinal and Transverse Diffusion in Hydrocarbons derived from Distributions of Single Electrons

Time-of-flight observation of electron swarm in methane

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