  China spallation neutron source(CSNS) is a high intensity proton accelerator
based facility, and its accelerator complex includes two main parts: an H-
linac and a rapid cycling synchrotron(RCS). The rcs accumulates the 80MeV
proton beam, and accelerates it to 1.6GeV, with a repetition rate of 25 Hz. The
AC dipole of the RCS is operated at a 25Hz sinusoidal alternating current which
causes severe vibration. The vibration will influence the long-term safety and
reliable operation of the magnet. The dipole magnet of RCS is active vibration
equipment which is different with ground vibration accelerator. It is very
important to design and research the dynamic characteristic of the
dipole-girder system. This paper takes the dipole and girder as a specific
model system, a method for researching the dynamic characteristic of the system
is put forward by combining theoretical calculation with experimental testing.
The ansys simulation method plays a very important role in the girder structure
design stage. With the method the mechanical resonance phenomenon was avoided
in the girder design time. At the same time the dipole vibratory force will
influence the other equipment through the girder. It is necessary to isolate
and decrease the dipole vibration. So a new isolator was designed to isolate
the vibratory force and decrease the vibration amplitude of the magnet.
