Two-frequency beam-loading compensation in the drive-beam accelerator of the CLIC Test Facility

Author

Braun, H.H. ; Valentini, M.

Author_Institution

CERN, Geneva, Switzerland

Volume

5

fYear

1999

fDate

1999

Firstpage

3402

Abstract

The CLIC Test Facility (CTF) is a prototype two-beam accelerator, in which a high-current “drive beam” is used to generate the RF power for the main-beam accelerator. The drive-beam accelerator consists of two S-band structures which accelerate a bunch train with a total charge of 500 nC. The substantial beam loading is compensated by operating the two accelerating structures at 7.81 MHz above and below the bunch repetition frequency, respectively. This introduces a change of RF phase from bunch to bunch, which leads, together with off-crest injection into the accelerator, to an approximate compensation of the beam loading. Due to the sinusoidal time-dependency of the RF field, an energy spread of about 7% remains in the bunch train. A set of idler cavities has been installed to reduce this residual energy spread further. In this paper, the considerations that motivated the choice of the parameters of the beam-loading compensation system, together with the experimental results, are presented

Keywords

accelerator RF systems; accelerator cavities; linear colliders; particle beam bunching; particle beam injection; test facilities; 7.81 MHz; CLIC Test Facility; CTF; RF phase; S-band structures; beam loading; bunch train; drive-beam accelerator; idler cavities; off-crest injection; prototype two-beam accelerator; two-frequency beam-loading compensation; Acceleration; Large Hadron Collider; Life estimation; Optical pulses; Particle beams; Prototypes; Radio frequency; Test facilities; Testing; Tin;

fLanguage

English

Publisher

ieee

Conference_Titel

Particle Accelerator Conference, 1999. Proceedings of the 1999

Conference_Location

New York, NY

Print_ISBN

0-7803-5573-3

Type

conf

DOI

10.1109/PAC.1999.792317

Filename

792317