Study on the effects of chromaticity and magnetic field tracking errors at CSNS/RCS

Abstract

Abstract:The Rapid Cycling Synchrotron (RCS) is a key component of the China Spallation Neutron Source (CSNS). For this type of high intensity proton synchrotron, the chromaticity, space charge effects and magnetic field tracking errors between the quadrupoles and the dipoles can induce beta function distortion and tune shift, and induce resonances. In this paper the combined effects of chromaticity, magnetic field tracking errors and space charge on beam dynamics at CSNS/RCS are studied systemically. 3-D simulations with different magnetic field tracking errors are performed by using the code ORBIT, and the simulation results are compared with the case without tracking errors. The lattice of the CSNS/ RCS is trip let based four-fold structure. Table 1 Effects on Lattice functionThe natural chromat icity of the CSNS/ RCS lattice is (-4.3, -8.2), which can produce the tune shift of (±0.04, ±0.08) for the mo mentum spread of p/p=±0.01 (The maximu m mo mentu m spread during accelerat ion according to the simu lation results ). The dependence of the Beta functions on the mo mentu m spread along a super-period without chromatic correct ion is shown in Fig.