Abstract
The Cornell Electron-Positron Storage Ring (CESR) has a longitudinal dipole-coupled-bunch instability that limits the total amount of current that can be stored in the ring without feedback. As a result, it is one of the major limitations for higher stored current and luminosity. This paper reports the measurements of multiple bunch longitudinal dynamics done on CESR with a streak camera. The camera was used to measure the dependence of the bunch distribution on current and accelerating rf voltage, for multiple bunches stored in CESR, as well as the effects of the longitudinal instability on the bunch distribution. Measurements of the beam's longitudinal bunch distribution with multiple bunches present in the ring help give an understanding of the instability, how it affects the bunch distribution, and possibly give insight into a cure of the instability.
Highlights
The measurements of Cornell Electron-Positron Storage Ring (CESR) provide information about the behavior of the bunch during multiple bunch operations, when the dipole-coupled-bunch longitudinal instability was present in CESR
The general conclusions from the measurements are that in terms of longitudinal dynamics there is no difference between the positrons and electrons in CESR
The coupled-bunch longitudinal instability is a dipole mode instability, which may be damped by a strong feedback system thereby increasing the current threshold [7]
Summary
Multiple bunches refers to more than one bunch of electrons or positrons being present in the Cornell ElectronPositron Storage Ring (CESR) at one time. We begin with the time-independent longitudinal phase sult, the wakefields can cause a change in the synchrotron space density rt, f, which can be written in actionoscillation frequency, a change in the bunch distribution, angle coordinates in terms of the synchrotron oscillation or instability. These collective effects can cause collective amplitude t and phase f. The beam-induced field depends on the amount of charge in the bunch and the bunch distribution It can be concluded from Eq (1) that azimuthal structure in longitudinal phase space is present when synchrotron sidebands are observed [4]. Higher order terms (above the quadrupole mode) have been observed at CESR, but they have been either induced or driven from the dipole mode so they are not the primary mode of interest
Sign-in/Register to view highlights & summary 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 callMore From: Physical Review Special Topics - Accelerators and Beams
Disclaimer: 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.
