  China Spallation Neutron Source is a high intensity proton accelerator based
facility, and its accelerator complex includes two main parts an H- linac and a
rapid cycling synchrotron. The RCS accumulates the 80MeV proton beam, and
accelerates it to 1.6GeV, with a repetition rate of 25Hz. The dipole of the
CSNS RCS is operated at a 25 Hz sinusoidal alternating current which causes
severe vibrate. The vibration will influence the long term safety and reliable
operation of the magnet. The dipole of the CSNS RCS is an active vibration
equipment which is different from the ground vibration accelerator. It is very
important to design and study the dynamic characteristics of the dipole girder
system. This paper takes the dipole and girder as a specific model system, a
method for studying the dynamic characteristics of the system is put forward by
combining theoretical calculation with experimental testing. The modal
parameters with and without vibration isolator of the dipole girder system are
obtain through ANSYS simulation and testing. Then the dynamic response of the
system is calculated with modal analysis and vibration testing data. The dipole
girder takes four-point support system which maybe appears over constrained in
the progress of adjustment. The dynamic characteristics and dynamic response of
the three point girder system were studied with the same method.
