合肥光源钮扣型束流位置检测器的离线标定

摘要

为满足合肥光源重大维修改造项目对储存环束流位置测量的高精度要求，对钮扣束流位置检测器（BPM ）电极进行了重新设计，本文对新设计的BPM进行特征阻抗、分布电容和标定系数等参数离线标定。采用时域反射计（TDR）测量其阻抗特性和分布电容，测量结果表明，50Ω标准阻抗测试电缆与BPM Feedthrough连接处的阻抗一致性较好，说明其特性符合设计的50Ω阻抗，计算得到分布电容约为2.9 pF ，满足设计要求。通过天线法进行标定，分别采用差比和法与对数比法得到直观的mapping图，计算得到BPM的水平和垂直方向的灵敏度，差比和法与对数比法获得的灵敏度相对偏差在垂直方向小于0.5％，水平方向小于2.8％，离线标定获得的各项参数均满足要求。%According to the high precision requirements of the Hefei Light Source major maintenance and reconstruction project , a new button type beam position monitor (BPM) was designed for HLS Ⅱ electron storage ring .The characteristic impedance and distributed capacitance of button pickup were measured by time-domain reflectometer (TDR) ,and scaling coefficient of the new BPM was determined through antenna method .The TDR test results show that the impedance of pickup is 50 Ω which matches the cable impedance ,and the capacitance is about 2.9 pF w hich meets design requirements . Furthermore , the intuitive mapping diagram and calibration factor of beam position were obtained by antenna scanning .Compared with the design value ,the sensitivity deviation of new BPM is less than 0.5% in the vertical direction and less than 2.8% in the horizontal direction .