Power coupling

Power coupling is the subject of a huge amount of literature and material since for each particular RF structure it is necessary to design a coupler that satisfies some requirements, and several approaches are in principle possible. The choice of one coupler with respect to another depends on the particular RF design expertise. Nevertheless some 'design criteria' can be adopted and the scope of this paper is to give an overview of the basic concepts in power coupler design and techniques. We illustrate both the cases of normal-conducting and superconducting structures as well as the cases of standing-wave and travelling-wave structures. Problems related to field distortion induced by couplers, pulsed heating, and multipacting are also addressed. Finally a couple of design techniques using electromagnetic codes are illustrated. The paper brings together pictures, data, and information from several works reported in the references and I would like to thank all the authors of the papers.Comment: 23 pages, contribution to the CAS - CERN Accelerator School: Specialised Course on RF for Accelerators; 8 - 17 Jun 2010, Ebeltoft, Denmar

Rf Deflector Based Sub-Ps Beam Diagnostics:. Application to Fel and Advanced Accelerators

RF deflectors are very promising devices for longitudinal and transverse phase space characterization and beam manipulation in advanced accelerators. Measurement setups for longitudinal pulse shape as well as phase space and transverse beam slice emittance characterizations are described as well the main design criteria of traveling wave and standing wave RF deflectors used for beam diagnostics putting in evidence the advantages or disadvantages of the two devices in terms of performances, required power and power limitations

EuPRAXIA@SPARC_LAB Conceptual Design Report

It is widely accepted by the international scientific community that a fundamental milestone towards the realization of a plasma driven future Linear Collider (LC) will be the integration of high gradient accelerating plasma modules in a short wavelength Free Electron Laser (FEL) user facility. To this end, in October 2019 the Horizon2020 Design Study EuPRAXIA (European Plasma Research Accelerator with eXcellence In Applications) will propose the first European Research Infrastructure that is dedicated to demonstrate usability of plasma accelerators delivering high brightness beams up to 1-5 GeV for users. In this report we discuss the EuPRAXIA@ SPARC_LAB project, intended to put forward LNF as host of the EuPRAXIA European Facility. The EuPRAXIA@SPARC_- LAB facility will equip LNF with a unique combination of a high brightness GeV-range electron beam generated in a state-of-the-art X-band RF linac, a 0.5 PW-class laser system and the first 5th generation light source driven by a plasma accelerator. These unique features will enable at LNF new promising synergies between fundamental physics oriented research and high social impact applications, especially in the domain of Key Enabling Technologies (KET) and Smart Specialisation Strategies (S3)

TE Wave Measurement and Modeling

In the TE wave method, microwaves are coupled into the beam-pipe and the effect of the electron cloud on these microwaves is measured. An electron cloud (EC) density can then be calculated from this measurement. There are two analysis methods currently in use. The first treats the microwaves as being transmitted from one point to another in the accelerator. The second more recent method, treats the beam-pipe as a resonant cavity. This paper will summarize the reasons for adopting the resonant TE wave analysis as well as give examples from CESRTA and DA{\Phi}NE of resonant beam-pipe. The results of bead-pull bench measurements will show some possible standing wave patterns, including a cutoff mode (evanescent) where the field decreases exponentially with distance from the drive point. We will outline other recent developments in the TE wave method including VORPAL simulations of microwave resonances, as well as the simulation of transmission in the presence of both an electron cloud and magnetic fields.Comment: Presented at ECLOUD'12: Joint INFN-CERN-EuCARD-AccNet Workshop on Electron-Cloud Effects, La Biodola, Isola d'Elba, Italy, 5-9 June 2012; CERN-2013-002, pp. 193-20

Longitudinal beam dynamics simulation in electron rings in strong rf focusing regime

Obtaining very short bunches in an electron storage ring is one of the frontiers of the accelerator physics. The strong rf focusing (SRFF) is a way to have short bunches at a given position in the ring, thanks to the principle of the bunch length modulation. Until now, the bunch length modulation has been studied only in the limit of zero current; in this paper we present the results of a simulation code suitable to study the effects of coherent synchrotron radiation and vacuum chamber wakefields on the single bunch longitudinal dynamics in the SRFF regime . The code has been applied to three different lattices that can be realized in the Frascati e^{+}/e^{-} collider DAΦNE for a possible experiment on bunch length modulation