Efforts by numerous institutions have been ongoing over the past decade to develop a Dielectric-Loaded Accelerating (DLA) structure capable of supporting high gradient acceleration when driven by an external rf source. Multipactor is the major issue limiting the gradient that was revealed in earlier experiments. A theoretical model predicts a solenoid field within an optimal range of field stre...

Breakdown of dielectric radio frequency (RF) windows is an important issue for particle accelerators and high-power RF sources. One the common reasons window failure multipactor on a surface. The may be responsible excessive heating discharge charges that accumulated in ceramic due to secondary emission. In this study, comprehensive self-consistent particle-in-cell simulations with space charge...

A multipactor discharge is a resonant condition for electrons in an alternating electric field. This discharge can be disruptive to radio frequency (RF) circuits, cavities, and resonators. The Coaxial Multipactor Experiment (CMX) investigates these discharges in parallel plate and coaxial transmission line geometries at frequencies from 40 to 150 MHz with goals of measuring the electron energy ...

Abstract This paper presents the design of a sixth-order cross-coupled L-band filter, specifically intended for space applications. The solution was based on principle stepped impedance coaxial resonators (SIRs), which allowed us to fulfill several electrical and size specifications more particularly high multipactor threshold. degrees freedom afforded by proposed topology offer wide choice con...

We present secondary electron yield (SEY) characterization of high porosity surfaces for multipactor-free microwave components. first calculate the SEYs through using Monte Carlo simulations. demonstrate that these can be treated as homogeneous materials with low effective SEYs. prove a significant SEY reduction is attainable by porosities, and above certain level, entire surface falls below un...

We measured the bulk optical damage thresholds of pure and Nd-doped ceramic yttrium aluminum garnet (YAG), and of pure, Nd-doped, Cr-doped, and Yb-doped crystalline YAG. We used 9.9 ns, 1064 nm, single-longitudinal mode, TEM00 pulses, to determine that the breakdown thresholds are deterministic, with multiple-pulse thresholds ranging from 1.1 to 2.2 kJ/cm2.

In spite of the mutual repulsion among the space charges, a new phase-focusing mechanism is discovered whereby the leading edge of the multipactor discharge in an rf circuit grows at the expense of the trailing edge. This effect arises from the different impact energies, and hence different secondary electron yields, experienced by different portions of the discharge. This phase focusing mechan...

Vacuum-dielectric interface is the most vulnerable part of vacuum insulation systems where surface electrical breakdown prone to happen, hence severely restricts development advanced electro-vacuum devices with large capacity and its miniaturisation. Generally, a direct effective way improve alleviate initiation multipactor phenomena. Inspired by this approach, authors report 3D-printed structu...

An 11.4 GHz standing wave Dielectric Loaded Accelerating (DLA) structure was recently developed. The structure is designed to achieve a 120 MV/m gradient powered by a 10 MW 200 ns rf pulse from the X-band Magnicon at the Naval Research Laboratory (NRL). The structure uses on-axis rf coupling, which helps to localize the maximum EM fields within the dielectric region. Bench testing shows excelle...