Title :
Local bump method for measurement of transverse impedance of narrow-gap ID chambers in storage rings
Author :
Ernery, L. ; Decker, G. ; Galayda, J.
Author_Institution :
Adv. Photon Source, Argonne Nat. Lab., IL, USA
Abstract :
A local bump method has been proposed to determine the transverse impedance of narrow-gap insertion-device (ID) vacuum chambers. As a stored bunch passes through an impedance section, the bunch receives a small transverse kick, which depends on the bunch total charge, the bunch length, and the transverse position. The kick can be measured as a function of orbit by applying a four-magnet bump and forcing closure by a running orbit correction. We measured the ID vacuum chambers with apertures of 5 mm and 8 mm, and a straight section with regular 42 mm aperture extrusion. Two types of local bumps are applied: a parallel and an angle bump, each of which emphasizes the impedance of different parts of the straight section
Keywords :
accelerator magnets; electromagnets; particle beam bunching; particle beam dynamics; particle beam stability; storage rings; wigglers; 42 mm; 5 mm; 8 mm; bunch length; bunch total charge; four-magnet bump; local bump method; narrow-gap ID chambers; narrow-gap insertion-device vacuum chambers; running orbit correction; storage rings; stored bunch; transverse impedance; transverse kick; transverse position; Apertures; Extraterrestrial measurements; History; Impedance measurement; Intrusion detection; Laboratories; Monitoring; Phase measurement; Position measurement; Storage rings;
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.2001.987195
