Residual orbit of BC bump for CSNS/RCS

Abstract

In a beam cycle, there is a chicane bump (BC bump) in the injection region of China Spallation Neutron Source (CSNS). It is a core part of the injection system and the important guarantee that the Linac beam injecting into the rapid cycling synchrotron (RCS). During the beam commissioning, the residual orbit of BC bump, i.e. the closedorbit distortion (COD) due to the imperfect BC bump, was an important problem which can affect the orbit correction and beam loss control of the RCS. In this paper, a method to measure the residual orbit of BC bump was studied and given. By using the three auxiliary powers of BC magnets, a method to correct the residual orbit of BC bump was developed. The numerical simulation results showed that the measurement and correction methods had worked well and they can be applied to the beam commissioning of CSNS/RCS. The measurement results in the machine study showed that the residual orbit of BC bump is not large and can be corrected by the three auxiliary powers of BC magnets.