Abstract
In the CERN Antiproton Accumulator, transverse instabilities set in at circulating intensities as low as 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sup> p(p), mainly because of the unusually small variation of Q vs. momentum. The bunched p "test" beam is lost due to head-tail instabilities, and vertical coasting beam modes of the p stack lead to an intolerable emittance growth. Based on estimated AA transverse impedances, a fairly simple feedback system was built. Particular features are (i) low power requirements (10 W); (ii) housing the electronics outside the tunnel; (iii) a "double damper" arrangement enabling the system to tackle simultaneously the p stack and the counter-rotating p test beam; (iv) the system's use for controlled beam blow-up to determine machilne apertures. Whereas the measured growth rates match the resistive wall impedance, significantly higher damping rates are required to eliminate all coasting beam modes, for yet unknown reasons.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
