Title :
Experiment of the RF feedback using a parallel comb filter
Author :
Yoshimoto, S. ; Ezura, E. ; Akai, K. ; Takashima, T.
Author_Institution :
KEK, Nat. Lab. for High Energy Phys., Ibaraki, Japan
Abstract :
In high beam-current storage rings like KEK B-factory, severe coupled-bunch longitudinal instability can be driven by the accelerating mode of significantly detuned RF cavities. The RF feedback with a comb filter, which can reduce the effective cavity impedance at the synchrotron sidebands of the revolution harmonics, is a possible way to damp the instability. This paper describes the results of the experimental RF feedback loop, which includes a N-path filter referred to as a parallel comb filter, a choke mode cavity, and a 1.2 MW klystron. With the feedback, the real part of the cavity impedance was reduced by 16 dB to 24 dB, at the five synchrotron sidebands 100 kHz apart each other
Keywords :
accelerator RF systems; accelerator control systems; beam handling techniques; colliding beam accelerators; electron accelerators; feedback; harmonics; storage rings; KEK B-factory; N-path filter; RF feedback; choke mode cavity; effective cavity impedance; high beam-current storage rings; klystron; parallel comb filter; revolution harmonics; severe coupled-bunch longitudinal instability; significantly detuned RF cavities; synchrotron sidebands; Acceleration; Feedback loop; Impedance; Inductors; Klystrons; Optical coupling; Power harmonic filters; Radio frequency; Storage rings; Synchrotrons;
Conference_Titel :
Particle Accelerator Conference, 1995., Proceedings of the 1995
Conference_Location :
Dallas, TX
Print_ISBN :
0-7803-2934-1
DOI :
10.1109/PAC.1995.505656
