SOLEIL, Gif-sur-Yvette
Beam orbit stability is a crucial parameter for 3rd generation light sources in order to achieve their optimum performance. Sub-micron stability is now a common requirement for vertical beam position. To reach such performance, Global Orbit Feedback Systems are mandatory. This paper describes the different design approaches for Global Orbit Feedback Systems. A few machines can use a single set of strong correctors. Most machines have their strong corrector bandwidth limited by eddy currents in aluminium vacuum chamber, or power-supplies speed or digitization granularity. Then, a second set of fast correctors is required for high frequency correction. But Fast and Slow Orbit Feedback Systems cannot work together with a common frequency range, they fight each other. An earlier solution has been to separate fast and slow systems by a frequency deadband. This approach does not allow correcting efficiently the orbit shift due to the gap movements of the increasingly sophisticated insertion devices that are installed on new machines. The different solutions that have been recently implemented are reviewed.
NSRRC, Hsinchu
The BPM electronics of the Taiwan Light Source (TLS) have been upgraded to the Libera Brilliance in August 2008 to improve performance and functionality. Orbit feedback system is also migrated into fast orbit feedback system to enhance orbit stability. Infrastructure of the orbit acquisition system and orbit feedback system has been reconstructed to accommodate with new BPM electronics and satisfy requirements of fast orbit feedback loops. Gigabit Ethernet grouping was adopted for the data transfer rate of 10 kHz between BPM and the orbit feedback system. A summary of the efforts and performance of this upgrade will be presented in this report.