Abstract:
The fast stability of the closed orbit of the electron beam
at the Advanced Light Source (ALS) at Lawrence Berkeley
National Laboratory fulfills user requirements so far
with-out any fast active correction system. In the range
between 0.1 and 500 Hz the integrated rms closed orbit
motion is significantly below one tenth of one sigma
beamsizes. For the future there is some user demand to
improve this stabil-ity further. Moreover, the expansion of
the capabilities of the ALS creates new sources of closed
orbit noise. There-fore the design of a fast, global orbit
feedback system has been started in conjunction with a
general upgrade of the ALS control system. It will initially
operate with an up-date rate of 500 Hz 1 kHz, will include
24 beam position monitors and corrector magnets in each
plane and will use standard computer and networking
architecture. The sys-tem design, measurements of transfer
functions and tests with small prototype systems will be
presented.