Use of dual rf systems to accelerate large longitudinal emittance intense beam in a synchrotron

Abstract

Preserving the beam brightness and emittance during acceleration for high energy collider operation is a long-standing challenge for synchrotron injectors. Radio-frequency manipulation schemes used to produce bright bunches in these synchrotrons are often responsible for both beam loss and for the emittance dilution; the impact of such effects becomes the main obstacle to improve the collider luminosity. We have developed a scheme for acceleration of intense beam bunches of large longitudinal emittance using two rf systems. The development of such a method primarily came about to improve the overall injection to extraction efficiency of the antiproton beam in the Main Injector used for the proton-antiproton collider operation of the Tevatron at Fermilab. This technique is quite general and can be applied at other facilities. Multiparticle beam dynamics simulations of the scheme have shown that one can eliminate the beam loss and minimize the emittance growth. The scheme has been demonstrated with beam experiments in the Main Injector using the 2.5 and 53 MHz rf systems with harmonic ratio of 1∶21.