腔式束流位置探测器的设计与实验研究

Study of cavity beam position monitor

束流位置探测器对自由电子激光装置的研制和运行具有重要的意义。其中,腔式束流位置探测器(腔式BPM)又以其高精度、高分辨率的特点而得到广泛的应用。本文对应用于上海深紫外自由电子激光装置上的腔式BPM进行了理论分析、模拟计算和BPM腔的测量等方面的研究。

BPM system is essential for the operation of SASE FEL facilities. Among various types of BPMs, such as the button-type BPM or the stripline-type BPM, only the cavity BPM has the potential to achieve a higher beam position resolution. The amplitude of the TM110-mode excited by an off-center beam in the BPM cavity yields a signal proportional to the beam displacement and to the bunch charge; and the signal phase gives the direction of the displacement. This paper discusses the fundamental characteristics of cavity BPM, and reports our MAFIA simulations and RF measurement of an BPM cavity.