Related papers: Surface Analysis of OFE-Copper X-Band Accelerating…
X-band accelerator structures, meeting the Next Linear Collider (NLC) design requirements, have been found to suffer damage due to radio frequency (RF) breakdown when processed to high gradients. Improved understanding of these breakdown…
In an effort to locate the cause(s) of high electric-field breakdown in x-band accelerating structures, we have cleanly-autopsied (no debris added by post-operation structure disassembly) an RF-processed structure. Macroscopic localization…
RF processing studies of 1.8-m X-band (11.4 GHz) traveling wave structures at the Next Linear Collider Test Accelerator (NLCTA) have revealed breakdown-related damage at gradients lower than expected from earlier tests with standing wave…
Understanding the effects of RF breakdown in high-gradient accelerator structures on the accelerated beam is an extremely relevant aspect in the development of the Compact Linear Collider (CLIC) and is one of the main issues addressed at…
The occurrence of vacuum arcs or radio frequency (rf) breakdowns is one of the most prevalent factors limiting the high-gradient performance of normal conducting rf cavities in particle accelerators. In this paper, we search for the…
This work studies the suitability of a set of different materials for manufacturing of more efficient and durable Radio-Frequency Quadrupole (RFQ) structures compared to that currently used in many linear particle accelerators,…
During operation, the radio-frequency quadrupole (RFQ) of the LINAC4 at CERN is exposed to high electric fields, which can lead to vacuum breakdown. It is also subject to beam loss, which can cause surface modification, including…
Conditioning of a metal structure in a high-voltage system is the progressive development of resistance to vacuum arcing over the operational life of the system. This is, for instance, seen during the initial operation of radio frequency…
Vacuum breakdown in accelerator structures is a critical challenge that occurs under high electric fields. In environments subjected to hydrogen ion irradiation or high beam losses, such as in Radio-Frequency Quadrupoles (RFQ), residual…
We describe breakdown in 805 MHz rf accelerator cavities in terms of a number of self consistent mechanisms. We divide the breakdown process into three stages: 1) we model surface failure using molecular dynamics of fracture caused by…
We calculate the geometric luminosity loss caused by filamentation of transverse kicks, upright and skew quadrupolar errors due to discharges, so-called RF-breakdown, in the acceleration structures of a Linear Collider.
A plasma model is presented for the formation of ``cathode spots'' and subsequent crater development near field emission sites on a copper surface in the presence of a strong dc electric field. Adding to previously published models, we…
High-gradient acceleration is a key research area that could enable compact linear accelerators for future colliders, light sources, and other applications. In the pursuit of high-gradient operation, RF breakdown limits the attainable…
In the NLC (Next Linear Collider) small misalignments in each of the individual accelerator structures (or the accelerator cells) will give rise to wakefields which kick the beam from its electrical axis. This wakefield can cause BBU (Beam…
High-gradient linacs of next generation require novel accelerating structures which are compact, robust and cost-effective. Dedicated research and development have been launched in the linear-collider community. This paper focuses on the…
A novel quantity for predicting the high-gradient performance of radio frequency accelerating structures is presented. The quantity is motivated, derived and compared with earlier high-gradient limits and experiments. This new method models…
The application of a high electrical field on metallic surfaces leads to the well described phenomena of breakdown. In the classical scenario, explosive electron emission (EEE), breakdown (BD) originates from an emitting site (surface…
The low-level RF (LLRF) systems for linear accelerating structures are typically based on heterodyne architectures. The linear accelerators normally have many RF stations and multiple RF inputs and outputs for each station, so the…
The development of high gradient accelerating structures is one of the leading activities of the accelerator community. In the technological research of new construction methods for these devices, high-power testing is a critical step for…
We argue that the physics of unipolar arcs and surface cracks can help understand rf breakdown, and vacuum arc data. We outline a model of the basic mechanisms involved in breakdown and explore how the physics of unipolar arcs and cracks…