Slow orbit feedback at the ALS using MATLAB

The third generation Advanced Light Source (ALS) produces extremely bright and finely focused photon beams using undulators, wigglers, and bend magnets. In order to position the photon beams accurately, a slow global orbit feedback system has been developed. The dominant causes of orbit motion at the ALS are temperature variation and insertion device motion. This type of motion can be removed using slow global orbit feedback with a data rate of a few Hertz. The remaining orbit motion in the ALS is only 1-3 micron rms. Slow orbit feedback does not require high computational throughput. At the ALS, the global orbit feedback algorithm, based on the singular valued decomposition method, is coded in MATLAB* and runs on a control room workstation. Using the MATLAB* environment to develop, test, and run the storage ring control algorithms has proven to be a fast and efficient way to operate the ALS.