50 MHz transverse feedback system in the CERN ISR

Conference · Wed Jun 01 04:00:00 EDT 1977 · IEEE Trans. Nucl. Sci.; (United States)

OSTI ID:7294882

Carron, G; Myers, S; Thorndahl, L

One of the intensity limits in the ISR is imposed by the transverse coherent instability. The intensity at which the instability occurs may be raised by Landau damping, i.e., increasing the tune spread of the stacked beam. However, due to nonlinear resonances, the maximum tune spread is limited. A vertical feedback system which detects and damps the first eight modes of the instability has succeeded in increasing the intensity limit by a factor of approximately 1.6. Recently this factor has once again become insufficient due to the increase in intensity resulting from improvements in the longitudinal density and vacuum system. A new 50 MHz feedback system has now been installed which damps the first 166 modes of the instability. Hence at low chromaticity values the critical intensity is raised by around another factor of two. The electronic gain of this system decreases with frequency in order to limit the blow-up of vertical oscillations due to electronic noise and to reduce phase errors at high frequencies. The 50 MHz system has been used to explore the ISR vacuum limit to intensities of 39 A.

• Research Organization: CERN, Geneva
• OSTI ID: 7294882
• Conference Information: Journal Name: IEEE Trans. Nucl. Sci.; (United States) Journal Volume: NS-24:3
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
430400* -- Particle Accelerators-- Storage Rings
CERN ISR
CONTROL SYSTEMS
DAMPING
ELECTRONIC EQUIPMENT
FEEDBACK
INSTABILITY
NOISE
STORAGE RINGS