Experimental research on intense pulsed emission of carbon nanotube cathode

Yi, 谌怡 Shen; Liansheng, 夏连胜 Xia; Huang, 张篁 Zhang; Liu, Xingguang; Qingliang, 廖庆亮 Liao

doi:10.3788/hplpb20112303.0775

Cited by 7 publications

(2 citation statements)

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“…Liang et al [20] reported that, within the frequency range of 26.5-40.0 GHz, both the dielectric constant and dielectric loss of AlN/CNT composites increased significantly as the CNT content increased, and a high dielectric loss of 0.1−0.61 was achieved at 5 vol% CNT. Nonetheless, as CNTs have a very large specific surface area and a hollow tubular structure, they can adsorb a large amount of gas and may undergo out-gassing under a high vacuum environment, thus limiting their application in preparing vacuum electronic materials [21,22]. Graphene has an ultra-high thermal conductivity along the in-plane direction, while its layered structure readily produces a large heterogeneous interface between AlN matrix and graphene, which greatly reduces the thermal conductivity of AlN/graphene composite materials [7,8].…”

Section: Introductionmentioning

confidence: 99%

High-thermally Conductive AlN-based Microwave Attenuating Composite Ceramics with Spherical Graphite as Attenuating Agent

Xia

Jiang

Pan

et al. 2020

Preprint

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High-thermally conductive AlN-based microwave attenuating composite ceramics with spherical graphite (SG) as the attenuating agent were fabricated through hot-pressing sintering. The SG maintains its three-dimensional morphology within the sintered bodies, which considerably impedes the sintering of the composites to some extent but slightly influences on the growth of AlN grains. The addition of SG reduces the strength of the composites, but provides a moderate toughening effect at the optimal addition amount (3.8 MPa·m1/2 at 4 wt% SG). Benefiting from the low anisotropy, high thermal conductivity, and the three-dimensional morphology of SG, the composites exhibit a relatively higher thermal conductivity (76.82 W·m-1·k-1 at 10 wt% SG) compared with composites added with non-spherical attenuating agent. The dielectric constant and loss (8.2–12.4 GHz) increase remarkably as the amount of SG added increases up to 8 wt%, revealing that the incorporation of SG improves the dielectric property of the composite. The composite with 7 wt% SG exhibits the best absorption performance with a minimum reflection loss of -14 dB at 12.4 GHz and an effective absorbing bandwidth of 0.87 GHz. The excellent overall properties of the SG/AlN microwave attenuating composites render them as a promising material for various applications. Moreover, SG has a great potential as an attenuating agent for microwave attenuating composites due to its strong attenuation upon integration, high thermal conductivity, and low anisotropy.

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Section: Introductionmentioning

confidence: 99%

High-thermally Conductive AlN-based Microwave Attenuating Composite Ceramics with Spherical Graphite as Attenuating Agent

Xia

Jiang

Pan

et al. 2020

Preprint

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“…During the EEE process [20], the gas from the explosion vaporization of cathode material is ionized to form cathode plasma. But in the PFE process, the neutral gas which is desorbed from the cathode is ionized.…”

Section: Introductionmentioning

confidence: 99%

Plasma-induced field emission study of carbon nanotube cathode

Shen

Xia

Zhang

et al. 2011

Phys. Rev. ST Accel. Beams

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An investigation on the plasma-induced field emission (PFE) properties of a large area carbon nanotube (CNT) cathode on a 2 MeV linear induction accelerator injector is presented. Experimental results show that the cathode is able to emit intense electron beams. Intense electron beams of 14:9-127:8 A=cm 2 are obtained from the cathode. The CNT cathode desorbs gases from the CNTs during the PFE process. The fast cathode plasma expansion affects the diode perveance. The amount of outgassing is estimated to be 0:06-0:49 Pa Á L, and the ratio of outgassing and electron are roughly calculated to be within the range of 170-350 atoms per electron. The effect of the outgassing is analyzed, and the outgassing mass spectrum of the CNT cathode has been studied during the PFE. There is a significant desorption of CO 2 , N 2 ðCOÞ, and H 2 gases, which plays an important role during the PFE process. All the experiments demonstrate that the outgassing plays an important role in the formation of the cathode plasma. Moreover, the characteristic turn-on time of the CNT cathode was measured to be 39 ns.

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CNT/Cu composite cathode: A new approach to long lifetime for explosive emission cathode

Yang

Sun

et al. 2022

Journal of Applied Physics

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Carbon nanotube (CNT) cathodes have attracted much attention in recent years due to the advantages of large field enhancement factor and low emission threshold. However, the severe ablation under intense emission makes the lifetime short and therefore limits the application in the field such as high power microwave generation. To resolve this problem, this paper proposes to mix CNTs with metals, and a novel CNT/Cu composite cathode is manufactured. The lifetime experiments under voltage of 940 kV and repetition frequency of 20 Hz demonstrate that the lifetime of the CNT/Cu composite cathode is over 3 × 105 pulses, which is much longer than that of the normal copper cathode by at least one order of magnitude. The microscopic morphology analysis reveals that the CNT micro-protrusions and whiskers should be vital for the good emission property of the new cathode.

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Experimental research on intense pulsed emission of carbon nanotube cathode

Cited by 7 publications

References 0 publications

High-thermally Conductive AlN-based Microwave Attenuating Composite Ceramics with Spherical Graphite as Attenuating Agent

High-thermally Conductive AlN-based Microwave Attenuating Composite Ceramics with Spherical Graphite as Attenuating Agent

Plasma-induced field emission study of carbon nanotube cathode

CNT/Cu composite cathode: A new approach to long lifetime for explosive emission cathode

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