Priorities of cathode and anode contaminations in triggering the short-pulsed voltage breakdown in vacuum

Batrakov, A. V.; Onischenko, S. A.; Proskurovsky, D.I.; Johnson, D. J.

doi:10.1109/tdei.2006.1593400

Cited by 21 publications

(4 citation statements)

References 16 publications

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“…Radio frequency (RF) breakdown is a crucial factor that degrades the performance of high-gradient accelerating structures and high-power microwave (HPM) generators [1][2][3][4][5][6]. Many researchers have proposed that field electron emission (FEE) is considered to be strongly related to RF breakdown [7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Mechanism analysis of field electron emission of titanium

Tan¹,

Wu²,

Hua³

et al. 2023

Phys. Scr.

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Field electron emission (FEE) is generally considered to be closely correlated with radio frequency (RF) breakdown in accelerating structures and high-power microwave (HPM) devices. In this study, the field emission characteristics of titanium are investigated by using a field emission test system. With the increase of the number of field emission tests and stability tests, the repeatability of the field emission characteristic curve of titanium tends to be better, and the amplitude of the current oscillation in the stability tests gradually decreases, indicating that the field emission performance of titanium gradually becomes stable. Subsequently, the field emission characteristic curve of titanium is analyzed by adopting the field emission theory of metal microprotrusions. Combined with the analysis of the electric field enhancement effects caused by the surface morphology, the dominant effect of the metal microprotrusions on the FEE of titanium is excluded from the two aspects of the electric field enhancement factor and local maximum emission current density. At last, the field emission theory of dielectric micropoints is introduced to analyze the field emission characteristics of titanium. The electric field enhancement factor of 102 ~ 103 are explained theoretically. Simultaneously, the reasonable effective emission area and local emission current density are given, which can better explain the field emission phenomena of titanium, such as the sharp decrease in emission current and repeatability of the field emission curve. Hence, it is revealed that the key factor that dominates the FEE of titanium is the dielectric impurities on the surface, rather than the metal microprotrusions.

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Section: Introductionmentioning

confidence: 99%

Mechanism analysis of field electron emission of titanium

Tan¹,

Wu²,

Hua³

et al. 2023

Phys. Scr.

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“…However, with the continuous increase of microwave output power, the intensity of the electromagnetic field on the structure surfaces increases accordingly, which will inevitably lead to the occurrence of radio frequency (RF) breakdown. e existence of RF breakdown causes irreversible structural damage, produces large amount of plasma, results in pulse shortening, and ultimately limits the performance of RBWOs [15][16][17][18][19][20]. e concept of explosive-electron emission (EEE) has been developed by many researchers to explain the vacuum breakdown in RBWOs [21,22].…”

Section: Introductionmentioning

confidence: 99%

Analysis of Destructive Effects with Electron Bombardment in Slow-Wave Structures

Tan

Hua

et al. 2022

Laser Part. Beams

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Radio frequency (RF) breakdown can result in pulse shortening and seriously degrade the stability and reliability of relativistic backward wave oscillators (RBWOs). This paper discusses the energy range of electrons causing breakdown traces in slow-wave structures (SWSs) through particle-in-cell (PIC) simulation, numerical calculation, and experimental verification. The PIC simulation and numerical calculation results reveal that the energy of the majority of the field-induced electrons bombarding the SWS surfaces after being accelerated is less than 120 keV. Furthermore, the micro appearances of the breakdown traces in SWSs and the witness targets bombarded directly by electrons of various energy levels have been analyzed. Scanning electron microscope (SEM) shows that the breakdown traces are featured with corrugated morphologies with a wide range and a shallow depth. A mass of craters emerge in the vicinity of the corrugated morphologies. These appearances are quite similar to destructive traces impacted directly by low-energy electrons (around 160 keV). Thus, it is confirmed that the breakdown traces result from the bombardment of low-energy electrons. Therefore, the breakdown mechanism of field-emitted electrons impacting on the structure surfaces in RBWOs has been further improved.

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“…First, it is thought that electrically conductive microparticles raise the electric field between the microparticles and the cathode, thereby promoting field electron emission from the microprotrusions on the cathode, which leads to breakdown . Next, it is thought that electrically insulating microparticles raise the electric field between the microparticles and the cathode and promote field electron emission due to a microparticle‐vacuum‐electrode triple point being formed, which leads to breakdown . Additionally, in some cases, the microparticles act as microprotrusions on the electrode and the electric field enhancement coefficient β increases.…”

Section: Introductionmentioning

confidence: 99%

“…7 Next, it is thought that electrically insulating microparticles raise the electric field between the microparticles and the cathode and promote field electron emission due to a microparticlevacuum-electrode triple point being formed, which leads to breakdown. 8,9 Additionally, in some cases, the microparticles act as microprotrusions on the electrode and the electric field enhancement coefficient increases. This may also lead to breakdowns.…”

Section: Introductionmentioning

confidence: 99%

Monte Carlo simulation of microparticle motion in vacuum gap

Ejiri

Kumada

Hidaka

et al. 2018

Electrical Engineering Japan

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Breakdown voltages of vacuum gaps become lower when the gaps are contaminated by metallic and ceramic microparticles. In this paper, the motion of the microparticles in the gap is simulated using Monte Carlo method in order to evaluate the effect of parameters upon motion and the removal time of the microparticles. As the parameters, we focused on the material of the microparticle, the frequency, the peak value of the applied voltage, the gap length, and the diameter of the lower and upper electrodes. It turned out that the maximum time needed to remove all microparticles could be expressed as multiple regression function. It is suggested that the reliability of the microparticle removal can be increased by spark conditioning with opening/closing operation.

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Priorities of cathode and anode contaminations in triggering the short-pulsed voltage breakdown in vacuum

Cited by 21 publications

References 16 publications

Mechanism analysis of field electron emission of titanium

Mechanism analysis of field electron emission of titanium

Analysis of Destructive Effects with Electron Bombardment in Slow-Wave Structures

Monte Carlo simulation of microparticle motion in vacuum gap

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