Cathode-like luminescence from vacuum-dielectric interface induced by self-stabilizing secondary electron emission

Zhan, Jiasui; Mu, Hai‐Bao; Zhang, Guanjun; Huang, Xiaona; Shao, Xianjun; Deng, Jian

doi:10.1063/1.4738999

Cited by 16 publications

(5 citation statements)

References 14 publications

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“…A primitive above-surface model was first proposed by Boersch [11], who assumed that the initial emitted electrons from a cathode triple junction (CTJ) develop toward the anode along the dielectric surface and leave positive surface charges on the insulator. Prior to the final breakdown, electron flux over the dielectric could be stable in the saturated secondary electron emission (SSEE) stage [12], and a secondary electron emission avalanche (SEEA) serves as the origin of flashover [7]. Further developments were supplemented with the importance of near-surface outgassing as well as an ionization avalanche, introduced by Pillai and Anderson [13,14].…”

Section: Introductionmentioning

confidence: 99%

Mechanism of vacuum flashover on surface roughness

Guo¹,

Sun²,

Zhang³

et al. 2019

J. Phys. D: Appl. Phys.

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An investigation is conducted regarding the influence of surface roughness on the flashover strength of an insulator in vacuum. A series of experiments is first presented, showing the relationship between surface roughness and flashover voltage, combined with measurement of surface potential distribution. It is found that surface charging on a roughened dielectric is suppressed remarkably; also the flashover voltage threshold depicts a rise-and-fall trend with roughness increasing, exhibiting a voltage summit at a certain roughness value. In addition, optical observation is implemented to draw a parallel with an electron trajectory in vacuum. A proposal can therefore be made that multipactor expansion tends to be mitigated as electron bombardment on a dielectric occurs with a lower secondary electron yield. Then a theoretical model considering the microscopic physical process is established to explain the above phenomena, consisting of an internal charge migration layer, an interfacial electron absorption layer and an external electron obstruction layer. The validity of this theoretical model can be confirmed by obtaining the surface trap distribution, microscopic morphology and net secondary electron yield.

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Section: Introductionmentioning

confidence: 99%

Mechanism of vacuum flashover on surface roughness

Guo¹,

Sun²,

Zhang³

et al. 2019

J. Phys. D: Appl. Phys.

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“…Its mechanism, according to the widely accepted secondary electron emission avalanche (SEEA) theory firstly proposed by Boersch [3], can be ascribed to a single-surface multipactor discharge which also exists in high power microwave system [4,5]. Prior to the final breakdown, a self-sustained stage called saturated secondary electron emission (SSEE) stage can be preserved in nanosecond scale where electron flux and surface charges remain dynamically balanced combined with cathode-like luminescence [6]. Subsequently, desorbed gas builds up local pressure just above insulator until a critical pressure is reached, ultimately leading to a gaseous breakdown [7].…”

Section: Introductionmentioning

confidence: 99%

Estimation of surface flashover threshold in vacuum: from multipactor to discharge plasma

Sun¹,

Song²,

Guo³

et al. 2018

J. Phys. D: Appl. Phys.

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We propose a novel theoretical formula to estimate the surface flashover threshold in vacuum using the intrinsic properties of dielectric material as well as dielectric-vacuum configuration. The method is based on an above-surface model called secondary electron emission avalanche (SEEA), where flashover development can be divided into multipactor discharge, outgassing and an ionization avalanche which eventually leads to a plasma discharge. The transition from SEE-dominated regime to discharge plasma is supposed to be of significance where gas breakdown takes place within a nonuniform desorbed gas cloud in the vicinity of dielectric surface. Flashover occurs when specific space charge multiplication is achieved, yielding the critical pressure and breakdown voltage. The depiction of previous stages involves the secondary electron emission of dielectric materials, desorption and diffusion of adsorbed gas, ambient temperature, electrode structure, etc. Both particle-in-cell simulation and experiment data can corroborate the obtained theoretical results.

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“…When the impacting energy of electron is near to E i2 , a continuous multiplication or decline of positive charge density is more likely to occur, which is not stable. 5,9,10 In this SSEE state, electrons emitted from CTJ and secondary electrons emitted from surface will impact the surface continually, and they move towards anode but not lead to flashover. It is critical that the energy of an electron to make r being unity is about several tens of eV, 11,12 which is much higher than the band gap of general insulators (several eV).…”

Section: Theoretical Analysis On Ssee and Related Surface Charginmentioning

confidence: 99%

“…Such a process may be a special form of cathodoluminescence, and we call it as CLL. 5 In addition, on the basis of Ref. 4, the phase 1 of flashover process under steady voltage excitation could be separated into two stages, including phase 1(a) which means SSEE process and phase 1(b) which means general SEEA, as shown in Fig.…”

Section: Theoretical Analysis On Ssee and Related Surface Charginmentioning

confidence: 99%

Theoretical and simulation research on self-stabilizing secondary electron emission process across solid dielectrics in vacuum

Zhan

Huang

et al. 2013

Journal of Applied Physics

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Recently, the cathode-like luminescence phenomena are observed from the surface of solid dielectrics under steady-state high voltage excitation in vacuum, which is closely related to the self-stabilizing secondary electron emission (SSEE) occurring on insulator surface. In this paper, the theoretical analysis about surface charging based on the SSEE is made, and a one-dimensional Mont Carlo simulation on surface charge accumulation under DC voltage excitation is provided. The results reveal that surface charging process can be divided into three stages including initial accumulation, fast multiplication, and final stable stage. In the final stage, the SSEE phenomena are achieved and surface charges are invariable and reach up to a stable distribution. The simulated stable surface charge distribution is consistent with the theoretical deduction results, which confirms the existence of SSEE process.

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Cathode-like luminescence from vacuum-dielectric interface induced by self-stabilizing secondary electron emission

Cited by 16 publications

References 14 publications

Mechanism of vacuum flashover on surface roughness

Mechanism of vacuum flashover on surface roughness

Estimation of surface flashover threshold in vacuum: from multipactor to discharge plasma

Theoretical and simulation research on self-stabilizing secondary electron emission process across solid dielectrics in vacuum

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