Effect of dc voltage pulsing on high-vacuum electrical breakdowns near Cu surfaces

Abstract

Vacuum electrical breakdowns, also known as vacuum arcs, are a limiting factor in many devices that are based on application of high electric fields near their component surfaces. Understanding of processes that lead to breakdown events may help mitigating their appearance and suggest ways for improving operational efficiency of power-consuming devices. Stability of surface performance at a given value of the electric field is affected by the conditioning state, i.e. how long the surface was exposed to this field. Hence, optimization of the surface conditioning procedure can significantly speed up the preparatory steps for high-voltage applications. In this article, we use pulsed dc systems to optimize the surface conditioning procedure of copper electrodes, focusing on the effects of voltage recovery after breakdowns, variable repetition rates as well as long waiting times between pulsing runs. Despite the differences in the experimental scales, ranging from $10^{-4}$ s between pulses, up to pulsing breaks of $10^5$ s, the experiments show that the longer the idle time between the pulses, the more probable it is that the next pulse produces a breakdown. We also notice that secondary breakdowns, i.e. those which correlate with the previous ones, take place mainly during the voltage recovery stage. We link these events with deposition of residual atoms from vacuum on the electrode surfaces. Minimizing the number of pauses during the voltage recovery stage reduces power losses due to secondary breakdown events improving efficiency of the surface conditioning.

arXiv comment14 pages, 11 figures. Submitted to Physical Review Accelerators and Beams

References in corpus (8)

• Direct observation of vacuum arc evolution with nanosecond resolution
• Stochastic Model of Breakdown Nucleation under Intense Electric Fields
• Dynamic coupling between particle-in-cell and atomistic simulations
• Electromigration occurrences and its effects on metallic surfaces submitted to high electromagnetic field : A novel approach to breakdown in accelerators
• Growth mechanism for nanotips in high electric fields
• Atomistic behavior of metal surfaces under high electric fields
• Classification of vacuum arc breakdowns in a pulsed DC system
• Vacuum electrical breakdown conditioning study in a parallel plate electrode pulsed DC system

Cited by in corpus (2)

• Surface and sub-surface modifications of copper electrodes exposed to high-field conditioning at cryogenic temperatures
• Linear voltage recovery after a breakdown in a pulsed dc system