Investigation of a high voltage vacuum insulator for the DARHT accelerator

Cravey, W.R.; Devlin, G.L.; Downing, J.N.

doi:10.1109/ppc.1997.679395

Cited by 14 publications

(5 citation statements)

References 2 publications

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“…As with conventional insulators 8 , HGIs are able to withstand higher gradients as the duration of the applied voltage decreases 16,19,23 . We are currently developing a compact accelerator for proton radiotherapy which will take advantage of this effect 4 .…”

Section: Displacement Current Effectsmentioning

confidence: 96%

Vacuum insulator development for the dielectric wall accelerator

Harris

Blackfield

Caporaso

et al. 2008

Journal of Applied Physics

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At Lawrence Livermore National Laboratory, we are developing a new type of accelerator, known as a Dielectric Wall Accelerator, in which compact pulse forming lines directly apply an accelerating field to the beam through an insulating vacuum boundary. The electrical strength of this insulator may define the maximum gradient achievable in these machines. To increase the system gradient, we are using "High Gradient Insulators" composed of alternating layers of dielectric and metal for the vacuum insulator. In this paper, we present our recent results from experiment and simulation, including the first test of a High Gradient Insulator in a functioning Dielectric Wall Accelerator cell. a) Electronic mail: harris89@llnl.gov 2

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Section: Displacement Current Effectsmentioning

confidence: 96%

Vacuum insulator development for the dielectric wall accelerator

Harris

Blackfield

Caporaso

et al. 2008

Journal of Applied Physics

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“…Experience has shown that, in addition to being difficult to fabricate and maintain, HGIs with protruding vanes did not perform much differently than those without protruding vanes [23], and so most recently-built HGIs have used metal layers that are nominally flush with the dielectric surface. Finally, the thin metal layers typical of these designs are susceptible to vaporization under vacuum flashover conditions due to their small thermal mass, and this metal has been observed to be deposited on the surface of the HGI [7].…”

Section: Theories Of Operationmentioning

confidence: 99%

Multilayer High-Gradient Insulators

Harris

2006

2006 International Symposium on Discharges and Electrical Insulation in Vacuum

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High voltage systems operated in vacuum require insulating materials to maintain spacing between conductors held at different potentials, and may be used to maintain a nonconductive vacuum boundary. Traditional vacuum insulators generally consist of a single material, but insulating structures composed of alternating layers of dielectric and metal can also be built.These "High-Gradient Insulators" have been experimentally shown to withstand higher voltage gradients than comparable conventional insulators. As a result, they have application to a wide range of highvoltage vacuum systems where compact size is important. This paper describes ongoing research on these structures, as well as the current theoretical understanding driving this work.

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“…Surface flashover occurs in many vacuum electronic devices when the applied voltage exceeds a certain value, resulting in the failure of or damage to the device [ 5 , 6 , 7 , 8 , 9 , 10 ]. With the development of vacuum electronic devices toward high power, high frequency, and miniaturization, such as high-power klystron and high-power pseudo spark switch, the operating voltage of the device increases exponentially, making surface flashover of Al 2 O 3 ceramics become an important factor affecting their reliability and restricting the development of vacuum electronic devices [ 11 , 12 , 13 , 14 , 15 ]. Therefore, improving the surface voltage holdoff capacity of Al 2 O 3 ceramics has become one of the urgent problems to be solved in the field of vacuum electronics.…”

Section: Introductionmentioning

confidence: 99%

Study of TiO2 on the Voltage Holdoff Capacity of Cr/Mn-Doped Al2O3 Ceramic in Vacuum

et al. 2023

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With the development of vacuum electronic devices toward high power, high frequency, and miniaturization, the voltage holdoff capacity of the insulation materials in devices has also been raised to a higher demand. Cr/Mn/Ti-doped Al2O3 ceramics were prepared, and the bulk density, micromorphology, phase composition, resistivity, secondary electron emission coefficient, and surface flashover threshold in the vacuum of the Al2O3 were characterized. The results show that the addition of TiO2 to the Al2O3 ceramic can promote the sintering of the ceramic. The Cr/Mn/Ti-doped Al2O3 ceramic with a homogeneous microstructure can be obtained by an appropriate amount of TiO2 addition. In the process of the heat treatment, the TiO2 in the ceramics was reduced to a certain degree, which had an impact on the microstructure of the Al2O3 ceramic. Adding a small amount of TiO2 can improve the voltage holdoff performance in the vacuum. The value of the surface flashover threshold in the vacuum of the Cr/Mn/Ti-doped Al2O3 ceramic containing 1 wt.% TiO2 reached a value of 33 kV, which is 32% higher than that of the basic Al2O3 ceramic. The preparation of Al2O3 ceramics with a high voltage holdoff capacity in a vacuum provides fundamental technical support for the development of vacuum electronic devices.

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Investigation of a high voltage vacuum insulator for the DARHT accelerator

Cited by 14 publications

References 2 publications

Vacuum insulator development for the dielectric wall accelerator

Vacuum insulator development for the dielectric wall accelerator

Multilayer High-Gradient Insulators

Study of TiO2 on the Voltage Holdoff Capacity of Cr/Mn-Doped Al2O3 Ceramic in Vacuum

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