Explosive electron emission from a surface-modified carbon/carbon composite cathode

Zhou, Fan; Wan, Hong; Chuan, Junbing; Bai, Shuxin; Yang, Jie

doi:10.1088/0022-3727/46/30/305203

Cited by 10 publications

(7 citation statements)

References 23 publications

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“…By limiting the amount of current flowing throw the cathode, small craters were created just as expected [9]. More importantly, the lifetime of a laser-induced ecton, unlike the lifetime of ectons induced by a high voltage pulse, was limited to (4.1±0.4) ns [10], see Fig. 2.…”

Section: A Electron Emission From Laser-induced Ectons and Low-densimentioning

confidence: 84%

Emission of charged particles from laser-induced germanium ecton, vacuum spark, and vacuum arc

Porshyn

2020

Physics of Plasmas

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The highly resolved temporal evolution of laser-induced micro-explosions on a germanium surface is studied in a triode configuration for various gate charge levels and cathode currents. Electron emission from individual spots is directly imaged with a luminescence screen, showing that the opening angle of the source is about 30°. Electron bunches of several nanocoulombs per pulse in a time interval of about 150 ns are directly extracted to the anode without vacuum breakdown in the cathodic gap. When breakdown occurs, a remarkable change in the arc behavior of a threshold gap potential of around 1 kV is observed, which hints at two different evaporation mechanisms that depend on the cathodic fall of an individual spot. Therefore, for voltages well above the threshold, a fast gate discharge is observed within the first 100-200 ns, followed by fundamental plasma oscillations and an electron emission of several µC per pulse from the plasma boundary. Additionally, highly efficient emission of germanium ion clusters occurs, evidencing a stable twofold electron multiplication in the plasma, with a charge of several µC per pulse below the threshold.

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Section: A Electron Emission From Laser-induced Ectons and Low-densimentioning

confidence: 84%

Emission of charged particles from laser-induced germanium ecton, vacuum spark, and vacuum arc

Porshyn

2020

Physics of Plasmas

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“…It is generally believed that the process of plasma formation and the state of electron emission from the cathode is highly related to the surface micro-topography of the cathode 36 . When applying the voltage, the electric field at impurities, microprotrusions and sharp edges is much larger than the externally applied electric field, which causes electron emission 37 . In addition, the desorption, vaporization and ionization of surface contaminants at high voltage 38 , 39 will also affect the distribution of the electric field and the uniformity of the electron emission distribution.…”

Section: Resultsmentioning

confidence: 99%

Transient Radiation Imaging Based on a ZnO:Ga Single-Crystal Image Converter

Chen

Yao

et al. 2018

Sci Rep

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A ZnO:Ga single crystal with an applicable size of φ40 × 1 mm was prepared using the hydro-thermal method. The crystal exhibits good crystallinity and scintillation properties with a 63.94-arcsec full-width at half-maximum (FWHM) in the X-ray rocking curve (XRC) spectrum, 8% luminous non-uniformity, emission at 389 nm in the X-ray excited luminescence spectrum, fast response and 5.5% BGO luminous intensity. Furthermore, an X-ray pinhole imaging system of nanosecond temporal resolution with a ZnO:Ga single-crystal image converter was established to diagnose the cathode electron emission spatial distribution of an intense current diode. Results for shutter times of 4 μs and 5 ns were obtained, which directly represent the cathode electron spatial distribution throughout the entire pulse duration and during a certain moment of the pulse, respectively. The results demonstrate that the large ZnO:Ga single crystal can diagnose the spatial distribution of cathode electron emission in an intense current diode with high temporal resolution and provide new solutions for high-temporal-resolution diagnosis of a pulse radiation field.

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“…The carbon fiber has both high emission current and long cathode life [17], [18], but its microwave performance is inferior in high power (>1GW) RM due to difficulty in uniform preparation. Carbon nanotubes [19], [20], carbon/carbon composites [21], carbon epoxy resins [22], [23] and graphene [24], there are scarcely ever studies have shown their outstanding microwave performance than POCO graphite in RMs. Graphite cathode has always been the most common cathode material in RM experiments, owing to low emission threshold, less gas release, stable, low cost, and good repetition frequency performance [25]- [28].…”

Section: Introductionmentioning

confidence: 99%

Study on Flake Graphite Cathode Surface Microstructure in Relativistic Magnetrons

Chen

Jiang²,

Yang

et al. 2023

IEEE J. Electron Devices Soc.

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Flake graphite has excellent explosive electron emission performance for its plenty surface micro-bulges and high graphitization degree, but its advantages have rarely been studied in relativistic magnetrons. In this paper, flake graphite cathodes with different fineness were used in coaxial diodes and relativistic magnetrons, and the influence of the surface microstructure of the flake graphite cathode on the relativistic magnetron performance is demonstrated for the first time. The result showed that the graphite microstructure mainly affected the initiation stage of explosive emission. Moreover, the delay time is determined by the degree of graphitization and the surface microstructure of graphite, and the surface microstructure plays a major role. Under the applied voltage of ∼ 330kV-∼ 490kV, The finer flake graphite possessed a shorter emission delay and facilitated the microwave excitation. The excitation time of finer flake graphite is ∼ 3ns, and ∼ 5ns for lager flake graphite. After several operations of the relativistic magnetron, the edges of flake graphite were blunted, and the surface of the flake graphite appeared droplet-like areas formed by anode atom sputtering. This work reveals the advantages of the finer flake graphite cathode in the fast priming of the relativistic magnetron, thus shedding new light on cathode design of the relativistic magnetron.

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Explosive electron emission from a surface-modified carbon/carbon composite cathode

Cited by 10 publications

References 23 publications

Emission of charged particles from laser-induced germanium ecton, vacuum spark, and vacuum arc

Emission of charged particles from laser-induced germanium ecton, vacuum spark, and vacuum arc

Transient Radiation Imaging Based on a ZnO:Ga Single-Crystal Image Converter

Study on Flake Graphite Cathode Surface Microstructure in Relativistic Magnetrons

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