Bunch lengthening recently observed at PF-AR

Author

Ieiri, T. ; Kasuga, T. ; Minagawa, Y. ; Obina, T. ; Fujita, T.

Author_Institution

KEK, Tsukuba

Volume

5

fYear

2003

fDate

12-16 May 2003

Firstpage

3077

Lastpage

3079

Abstract

The PF-AR (Photon Factory Advanced Ring for pulse X-rays) at KEK has been renewed to upgrade the performance. In this project, new vacuum ducts were installed with shielding bellows instead of non-shielding aluminium bellows. Thus, the coupling impedance of the ring was improved due to the shields. Measuring the bunch lengthening before and after the installation, we evaluated the longitudinal impedance of the bellows in a low bunch current. When the bunch current was high enough, a longitudinal instability was observed, accompanied by higher-order coherent synchrotron oscillations. We discuss the instability and the impedance issues based on various phenomena and calculations

Keywords

beam handling equipment; electron accelerators; particle beam bunching; particle beam stability; storage rings; Photon Factory Advanced Ring; bellow longitudinal impedance; bunch current; bunch lengthening; coupling impedance; higher-order coherent synchrotron oscillations; longitudinal instability; pulse X-rays; shielding bellows; vacuum ducts; Acceleration; Bellows; Damping; Ducts; Hysteresis; Impedance; Length measurement; Storage rings; Synchrotrons; X-rays;

fLanguage

English

Publisher

ieee

Conference_Titel

Particle Accelerator Conference, 2003. PAC 2003. Proceedings of the

Conference_Location

Portland, OR

ISSN

1063-3928

Print_ISBN

0-7803-7738-9

Type

conf

DOI

10.1109/PAC.2003.1289819

Filename

1289819