A Second Harmonic (6-16 MHz) RF System with Feedback-Reduced Gap Impedance for Accelerating Flat-Topped Bunches in the CERN PS Booster

Since all experimental and theoretical evidence indicates that the beam intensity in the PSB is at present limited by the Laslett Q shift after trapping, a second harmonic accelerating system is being added with the aim of producing flat-topped bunches. Calculations indicate that the resulting improvement in bunching factor should permit an intensity increase of 25 to 40 %. Additionally, the bucket area is increased by 25 to 45 % depending on intensity.