Study of LAMPF H- Beam Position Motion and a Predictive Algorithm for Noise Reduction

The position noise in the LAMPF H- beam has been studied through examination of the autocorrelation and spectral density functions1 for position motion. The LAMPF H- beam is a pulsed 800-MeV beam, and the position of each beam pulse was treated as a discrete value. Also investigated was the reduction in position noise that can be attained with an algorithm that predicts beam position from the measured positions of previous beam pulses. The basis for this predictive algorithm is the calculation of the optimal linear estimator (see the appendix). We conclude that the majority of low-frequency noise occurs within the 10- to 15-Hz frequency range, and that, with a simple, 2-pulse predictive correction system, one could improve the noise in this frequency region by as much as a factor of 15.