Title :
Resistive-wall coupled-bunch instability driven by in-vacuum insertion devices in the SPring-8 storage ring
Author :
Nakamura, T. ; Soutome, K. ; Takao, M. ; Masaki, M. ; Hara, T.
Author_Institution :
JASRI/SPring-8, Hyogo, Japan
Abstract :
More than ten of in-vacuum type insertion devices are installed in the SPring-8- storage ring. When their gap was closed, we observed the low frequency vertical coupled bunch instability. We consider that this instability is driven by resistive-wall impedance caused by the magnet blocks made of NdFeB, of which conductivity is two order lower than aluminum. We calculated the resistive-wall impedance and measured its characteristics
Keywords :
X-ray production; accelerator magnets; electric impedance; electromagnets; electron accelerators; electron beams; particle beam bunching; particle beam diagnostics; particle beam stability; storage rings; wigglers; NdFeB; SPring-8 storage ring; closed gap; conductivity; low frequency vertical coupled bunch instability; magnet blocks; resistive-wall coupled-bunch instability; resistive-wall impedance; vacuum insertion devices; Aluminum; Conductivity; Frequency; Impedance measurement; Magnetic resonance; Magnetic shielding; Shape; Storage rings; Surface impedance; Surface treatment;
Conference_Titel :
Particle Accelerator Conference, 2001. PAC 2001. Proceedings of the 2001
Conference_Location :
Chicago, IL
Print_ISBN :
0-7803-7191-7
DOI :
10.1109/PAC.2001.987245
