Efficiency of copper and gold cathode in initiation of secondary emission in nitrogen-filled tube

Pejović, Momčilo M.; Marković, Vera; Ristić, Goran S.; Mekic, S

doi:10.1016/s0042-207x(97)00029-8

Cited by 7 publications

(5 citation statements)

References 14 publications

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“…For these τ values, the considerable concentrations of some neutral active states are also present [2], but because of their electrical neutrality and, consequently, their diffusion time greater than the drift time of positive ions, their role in SEE process is insignificant. On the basis of plateau lengths in figure 6, it can be estimated that the recombination times of positive ions are about 70 and 200 ms for CWT and MWT, respectively, and the value for MWT is in good agreement with our previous investigations [13,21]. These results give a very important conclusion that positive ions are more effectively absorbed at the copper than at the molybdenum glass.…”

Section: Recombination Processes At Molybdenum Glass and At Copper At...supporting

confidence: 86%

“…For such a process, the value of recombination coefficient should then be proportional to the atom concentration n and consequently it leads to 1/n decay. Else, it has been shown that nitrogen atom recombination processes also perform at copper [62], and that these processes are more intensive at gold than at copper [21]. On the other side, our investigations [41] showed that if the recombination process at the molybdenum glass is the second order one, while at the copper is the first order one, then our proposed numerical method fits the memory curves the best.…”

Section: Recombination Processes At Molybdenum Glass and At Copper At...mentioning

confidence: 70%

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Influence of tube wall material type and tube temperature on the recombination processes of nitrogen ions and atoms in afterglow

Ristić¹,

Milosavljević²,

Pejović³

2002

J. Phys. D: Appl. Phys.

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The recombination of positive ions and atoms during an afterglow period, created during previous electrical breakdown and gas discharge, at the molybdenum glass and copper is investigated using the time delay method. It has been shown that the recombination of the positive ions at the copper wall, while the atoms at the molybdenum wall, at room temperature, is more intensive. The temperature influence on the recombination of these particles at copper has also been monitored by the same method, showing that the positive ion recombination rate increases and atom recombination rate decreases with temperature.

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Section: Recombination Processes At Molybdenum Glass and At Copper At...supporting

confidence: 86%

Section: Recombination Processes At Molybdenum Glass and At Copper At...mentioning

confidence: 70%

Influence of tube wall material type and tube temperature on the recombination processes of nitrogen ions and atoms in afterglow

Ristić¹,

Milosavljević²,

Pejović³

2002

J. Phys. D: Appl. Phys.

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“…The moment method is based on the fact that shifted exponential distribution ( 14) is strongly asymmetrically and monotonically decreased, and, consequently, lim N →∞ = 0, where = t d min − t f . Figure 7 shows the comparison of the three different estimation methods of formative time, showing t f vs τ [28]. It can be seen that for small τ , t f estimated from Lauegram deviates from those obtained by other two methods.…”

Section: Analysis Of Time Delaymentioning

confidence: 94%

“…A very important parameter which affects the shape of the memory curve is the cathode material. The memory curves for nitrogen-filled tube at 6.7 mbar and 50% overvoltage, with Cu and Au cathodes are presented in figure 16 [57], showing that the curves have plateaus up to τ = 400 ms. The SEE is induced by the positive ions in this τ region, and t d changes very slightly.…”

Section: Memory Curvesmentioning

confidence: 99%

Electrical breakdown in low pressure gases

Pejović

Ristić

Karamarković

2002

J. Phys. D: Appl. Phys.

167

128

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The paper presents the results of investigation of the electrical breakdown in low pressure gases when the secondary electrons released from the cathode play the dominant role in the initiation of electrical breakdown. The secondary electrons are created by the charged and neutral species formed during the previous breakdown and discharge as well as by γ-rays. Electrical breakdown investigations are based on the measurements of electrical breakdown voltage and electrical breakdown time delay for gas-filled tubes with spherical electrodes with diameters much larger than an interelectrode distance. Stochastic nature of both the breakdown voltage and time delay are discussed and their distributions based on experimental data are shown. The methods for the determination of static breakdown voltage are also analysed. The influence of different parameters (overvoltage, cathode material and its surface purity, gas pressure, glow current, etc) on time delay are studied. A special attention is paid to the memory effect in various gases that depends on the positive ion recombination times, catalytic recombination times in the case of nitrogen and hydrogen, as well as metastable states deexcitation times in noble gases. The analysis of this effect is done by memory curves on the basis of which the presence of long-lived neutral active states can be followed to their very low concentrations when cosmic and environment radiation play the dominant role in electrical breakdown initiation.

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“…The decrease in N( 4 S) atom concentration in the late afterglow in the nitrogen-filled tube and air-filled tube has been analysed using expression (2), where it can be assumed, under our experimental conditions, that ts = td and P ≈ 1 (see section 3.2.2). Y , which comes from the recombination of N( 4 S) atoms at the electrodes, can be expressed as [79]…”

Section: Discussionmentioning

confidence: 99%

Analysis of processes responsible for the memory effect in air at low pressures

Pejović

Živanović

Karamarković

2010

Plasma Sources Sci. Technol.

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The memory effect in air at 0.7 and 6.6 mbar pressures, due to post-discharge survival of some species that affect subsequent breakdowns, was analysed using memory curves. In order to complete the analysis of the processes, memory curves for nitrogen have also been monitored, because air is 78% nitrogen. In an early afterglow, the memory effect in air, as well as in pure nitrogen, is a consequence of the same processes, i.e. the presence of N + 2 and N + 4 ions, formed by the collision between nitrogen metastable molecules from the previous discharge. The concentrations of nitrogen ions in an air-filled tube are lower than the concentration in a nitrogen-filled tube for a given afterglow period because of their recombination with O, O 2 and NO particles which are also present in the early afterglow in air. De-excitation of N 2 (A) and N 2 (a ) metastable molecules due to their collision with O 2 , O and O − particles also contributes to the reduction in the concentration of N + 2 and N + 4 ions. In the late afterglow in air and pure nitrogen, N( 4 S) atoms created during the previous discharge are responsible for the memory effect. In the early air afterglow N( 4 S) atoms can be formed by the collision of O + ions with N 2 (X) molecules. However, because of the relatively small concentration of these ions the most probable process is the recombination of N( 4 S) atoms with O 2 , O, NO and NO 2 particles. The net effect is that the concentration of N( 4 S) atoms in the late afterglow is less in air than in nitrogen. When the concentration of N( 4 S) atoms is sufficiently reduced, the breakdown is initiated by cosmic rays.

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Efficiency of copper and gold cathode in initiation of secondary emission in nitrogen-filled tube

Cited by 7 publications

References 14 publications

Influence of tube wall material type and tube temperature on the recombination processes of nitrogen ions and atoms in afterglow

Influence of tube wall material type and tube temperature on the recombination processes of nitrogen ions and atoms in afterglow

Electrical breakdown in low pressure gases

Analysis of processes responsible for the memory effect in air at low pressures

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