Reducing the coupled-bunch oscillation in the Fermilab Booster by optimizing RF voltage

Author

Shan, J.P. ; McGinnis, D. ; Tomlin, R.

Author_Institution

Fermi Nat. Accel. Lab., Batavia, IL, USA

fYear

1993

fDate

17-20 May 1993

Firstpage

3787

Abstract

In the Fermilab Booster, the coupled bunch oscillation is excited between transition and extraction by parasitic high order modes (HOM) in 17 RF cavities. the growth rate is determined by the coherent frequency shift and natural Landau damping due to nonlinearity of RF waveform. The passive damping and active feedback are normally used to reduce coherent frequency shift. Here we report that Landau damping can be enhanced through careful programming of RF voltage through the acceleration cycle. It is very effective during ramping where synchronous phase is big and bucket area is very sensitive to the RF voltage. In the case of a stationary bucket, the Landau damping is not sensitive to RF voltage

Keywords

beam handling techniques; cavity resonators; proton accelerators; synchrotrons; Fermilab Booster; RF cavities; RF voltage; RF waveform nonlinearity; acceleration cycle; active feedback; bucket area; coherent frequency shift; coupled-bunch oscillation reduction; extraction; growth rate; natural Landau damping; parasitic high order modes; passive damping; ramping; stationary bucket; synchronous phase; transition; Acceleration; Damping; Feedback; Radio frequency; Timing; Voltage;

fLanguage

English

Publisher

ieee

Conference_Titel

Particle Accelerator Conference, 1993., Proceedings of the 1993

Conference_Location

Washington, DC

Print_ISBN

0-7803-1203-1

Type

conf

DOI

10.1109/PAC.1993.309789

Filename

309789