Searcharxiv⌕ Search

arXiv · physics/0008101

The CLIC Main Linac Accelerating Structure

Abstract

This paper outlines the RF design of the CLIC (Compact Linear Collider) 30 GHz main linac accelerating structure and gives the resulting longitudinal and transverse mode properties. The critical requirement for multibunch operation, that transverse wakefields be suppressed by two orders of magnitude within 0.7 ns (twenty fundamental mode cycles), has been demonstrated in a recent ASSET experiment. The feasibility of operating the structure at an accelerating gradient of 150 MV/m for 130 ns has yet to be demonstrated. Damage of the internal copper surfaces due to high electric fields or resulting from metal fatigue induced by cyclic surface heating effects are a major concern requiring further study.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

I. Wilson, W. Wuensch. 2000-08-17. The CLIC Main Linac Accelerating Structure. https://arxiv.org/abs/physics/0008101

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

The problem of self-consistent particle phase space distributions for periodic focusing channels

Charged particle beams in equilibrium with their collective fields are represented by self-consistent phase space distributions. As the starting point, we assume the external focusing forces to act continuously on the beam. In the collisionless mean-field approximation, a broad class of stationary self-consistent particle phase space distributions can then be constructed. The method is reviewed how to determine the single-particle Hamiltonian of the focusing system for a given phase space density function. Subsequently, canonical transformations are used to relate this description to a beam passing through a non-continuous transport system. The correspondence is exact for the linear K-V model and provides an approximate matching prescription for distributions with nonlinear space-charge forces. The transverse Hamiltonian generally changes with the focusing strength, including in a rotationally symmetric periodic solenoid channel. Our computer simulations, presented in the second part of the paper, indicate very small rms-emittance changes for appropriately matched beams in the continuous and periodic solenoid channels investigated. The simulation for a periodic quadrupole channel yields a small persistent increase of the rms-emittance, whose physical interpretation requires control of numerical errors. Revised version of: Particle~Accelerators 39, 219--249 (1992)}

physics.acc-ph↗

Improved envelope and emittance description of particle beams using the Fokker-Planck approach

Beam dynamics calculations based on the collisionless Vlasov equation omit collisional correlations such as intra-beam scattering. For a short-correlated process dominated by small momentum changes, a Fokker-Planck equation can describe their effect on the one-particle distribution. From this equation we derive equations of motion for the beam envelopes and for the rms-emittances. Prescribed friction against an external bath is distinguished from momentum- and energy-conserving self-collisions. For the latter, an affine mean-flow approximation and a scalar relaxation coefficient give simple equations for temperature balancing within the beam. The longitudinal diffusion and temperature are expressed in terms of the physical random momentum rather than the signed effective longitudinal mass. The resulting growth-rate formulas apply to this reduced relaxation model. The original numerical examples are retained for comparison, with the limitations of the storage-ring and numerical-noise applications made explicit. Revised version of: Particle Accelerators~{\bf 45}, 229 (1994)

physics.acc-ph↗

Theoretical studies of envelope oscillations and instabilities of mismatched intense charged-particle beams in periodic focusing channels

The behavior of mismatched intense charged-particle beams in periodic transport channels of the solenoid and quadrupole type is studied theoretically. The envelope-oscillation frequencies of the mismatched beam are obtained by the smooth-approximation method and by numerical evaluation of the linearly perturbed K-V envelope equations. Phase shifts of the envelope oscillations and growth factors per focusing period in the case of instability are calculated for a solenoid and a magnetic quadrupole (FODO) channel using the parameters of the Maryland and GSI beam transport experiments. For comparison and the purpose of illustration, the K-V equations are integrated numerically, and envelope curves as well as single-particle trajectories for mismatched beams are shown in graphical form. In addition, computer simulation studies with the PARMILA code were performed, and results are presented both for K-V and a Gaussian distribution in transverse phase space.\\~\\ Revised version of: Particle~Accelerators~{\bf 14}, 227--260 (1984)}

physics.acc-ph↗