Related papers: Cavity and HOM Coupler Design for CEPC
Circular Electron-Positron Collider(CEPC) is one of the largest plans in high energy physics study at China, which would serve as Higgs Factory firstly and then upgrade to a hadron collider. In this paper we give the 50km and 100km design…
Higher order mode (HOM) damping is a crucial issue for the next generation of high-current energy recovery linacs (ERLs). Beam-induced HOMs can store sufficient energy in the superconducting RF (SRF) cavities, giving rise to beam…
An electron beam entering an accelerator cavity excites higher order modes (HOM). These are radiated to HOM couplers and subsequently damped. They can also be used to facilitate beam position monitoring. The modes excited by off-axis beams…
The Circular Electron Positron Collider (CEPC) is a large scientific project initiated and hosted by China, fostered through extensive collaboration with international partners. The complex comprises four accelerators: a 30 GeV Linac, a 1.1…
The design of both higher order mode (HOM) and fundamental power (FP) couplers for a unique New Low Surface Field (NLSF) cavity is presented. Here we present a study which uses ILC baseline couplers. The Balleyguier method of calculating…
Higher order mode (HOM) beam position monitors (BPM) are being developed for the 3.9 GHz third harmonic superconducting accelerating cavities at FLASH. The transverse beam position in a cavity can be determined utilizing beam-excited HOMs…
Superconducting cavities with low RF frequencies and heavy damping of higher order modes (HOM) are desired for the main accelerator of High Energy Photon Source (HEPS), a 6 GeV synchrotron light source promising ultralow emittance currently…
A new Higher Order Mode (HOM) damper was designed and tested for the Booster accelerator cavity at Fermilab. In anticipation of the PIP-II upgrade, it was discovered that the higher beam intensity of PIP-II may cause beam instability due to…
The Circular Electron Positron Collider (CEPC) is a large-scale future collider facility that can serve as a factory of the Higgs boson, the W boson and the Z boson. This document provides a brief summary of the CEPC physics potential and…
We will derive the general theory of the beam-breakup instability in recirculating linear accelerators with coupled beam optics and with polarized higher order dipole modes. The bunches do not have to be at the same RF phase during each…
In cavities, there exists not only the fundamental mode which is used to accelerate the beam but also higher order modes (HOMs). The higher order modes excited by beam can seriously affect beam quality, especially for the higher R/Q modes.…
The Circular Electron Positron Collider (CEPC) is a large international scientific facility proposed by the Chinese particle physics community to explore the Higgs boson and provide critical tests of the underlying fundamental physics…
We analyse the higher order modes (HOM's) in the 3.9GHz bunch shaping cavities installed in the FLASH facility at DESY. A suite of finite element computer codes (including HFSS and ACE3P) and globalised scattering matrix calculations (GSM)…
Polarized lepton beams are an important aspect in the design of the future 100 km-scale Circular Electron-Positron Collider (CEPC). Precision beam energy calibration using resonant depolarization, as well as longitudinally polarized…
This paper presents a study of beam alignment in accelerating cavities based on beam-excited higher order modes (HOM). Among the transverse HOMs, dipole modes have the dominant contribution, and may have an adverse effect on the beam…
The Circular Electron-Positron Collider (CEPC), a next-generation high-luminosity collider, employs a crab waist scheme to achieve ultrahigh $5 \times 10^{34} \, \text{cm}^{-2}\text{s}^{-1}$ luminosity at Higgs mode. Owing to the extremely…
The Circular Electron Positron Collider (CEPC) is a large international scientific project initiated and hosted by China. It is located in a 100-km circumference underground tunnel. The accelerator complex consists of a linear accelerator…
This study is focused on the development of a HOM-based BPM system for the ACC39 module currently installed and in operation at FLASH. A similar system is anticipated to be installed at XFEL. Coupled inter-cavity modes are simulated…
Higher-order mode (HOM) based intra-cavity beam diagnostics has been proved effectively and conveniently in superconducting radio-frequency (SRF) accelerators. Our recent research shows that the beam harmonics in the bunch train excited HOM…
The physics potential of the Circular Electron Positron Collider (CEPC) can be significantly strengthened by two detectors with complementary designs. A promising detector approach based on the Silicon Detector (SiD) designed for the…