行波电子直线加速器稳频系统的鉴频方法

A discriminating method of frequency stabilization system for travelling-wave LINAC

稳频系统的频率稳定度取决于谐振腔体的有载品质因素。因电子直线加速器的功率源是脉冲磁控管，其功率谱为形状，无限增大品质因素是不正确的，由帕息维尔定理知道腔体平方律检波器输出信号的面积正比于腔体输出能量，于是当磁控管振荡频率改变时，该信号面积的变化等效于腔体输出能量的变化，根据上述原理获得了品质因素的上限和推荐表达式。

The frequency stability of the frequency stabilization system is dependent on the loaded figure merit of the resonant cavity. To increase the figure merit infinitely is not correct because the power spectrum has a (siny/y)2 form for the pulse magnetron which is the power source of a LINAC. From the Parseval theory, area of the output signal of the square-law detector terminatied by the cavity will be directly proportional to output energy of the cavity so that the variation of the signal area is equivalent to that of output energy as oscillation frequency of the magnetron is changing. On the basis of this principle, a recommended expression and the upper limit of the figure merit are given.