Keywords: 
• 加速器 /
• 弯晶 /
• 束流控制 /
• 引出效率

Abstract: In the classical mechanics frame and with a dipole approximation the particle motion equation in the periodic bent crystal is reduced to the general pendulum equation with a damping term and the forced term by using the sine-squared potential.This paper discusses the problem of the sub-harmonic bifurcation of the periodic orbit and the stabilities of the channeling motion by using Melnikov method,so as to derive the critical condition and the dechanneling length of the periodic bent crystal.The results show that channeling motion must be stable in addition that the crystal length is smaller than the dechanneling length in order to ensure higher extracted efficiency.The analysis of the critical condition shows that the system stabilities are related to its parameters.Just by properly regulating the parameters of the system,the dynamic stabilities by the use of periodic bent crystal as beam control cell can be ensured.