Change in the Longitudinal Shape of Bunches in the U-70 Synchrotron by Noise RF-Gymnastics

Abstract

The shape of bunches in the U-70 proton accelerator needs to be changed in order to decrease the peak beam density per unit length and to decrease the Coulomb shift of the frequency of betatron oscillations on the input plateau. It is proposed that longitudinal noise pumping, based on introduction of a controllable phase noise into the accelerating rf voltage, be used for this. In the spring (2002) session of U-70, an experimental check was made of the principle of noise gymnastics on the input plateau. Measurements were performed on the beam which confirmed the workability of the method. A technical description of a model of the noise-pumping system is given. The experimental data obtained in testing the method are presented and compared with computational results.