八电极束流能散检测器的计算与标定

Calculation and calibration of eight-stripline beam energy spread monitor

针对合肥光源高亮度注入器设计了一种四轴对称八条带电极束流能散检测器(BESM),以实现束流能散的非拦截测量。理论推导了从BESM电信号中提取束流横向尺寸分量的公式。通过对BESM的灵敏度、阻抗匹配、电极的时域频域响应等的分析,确定了BESM的电极张角、半径、长度等各方面的物理参数。通过天线法对BESM进行了位置和四极分量的标定,得到了电中心相对于机械中心的偏移、BESM的位置灵敏度和四极分量灵敏度等参数。通过对多组电信号和位置信号的处理拟合出了机械位置与对数比电位置信号的相关多项式,并给出了四极分量关于束流横向尺寸、束流中心位置以及它们高次项的经验公式。

A beam energy spread monitor（BESM） with eight stripline electrodes in four-axis symmetry is designed for high-brightness injector in Hefei Light Source,to achieve the non-intercept measurement of beam energy spread.The formula to get the beam transverse size from BESM＇s electrode signals is figured out.With the sensitivity of the BESM,impedance matching,the time domain and frequence domain response of the stripline electrodes,etc.,being considered,the physical structure of this eight-stripline BESM,such as the electrode＇s open-angle,radius,length,is got.The eight-stripline BESM is calibrated with a calibration system by antenna method,and the offset between the electrical center and the mechanical center,the position sensitivity and the quadrupole component sensitivity of the BESM are got.The fitting polynomials of the mechanical position and the log-ratio electrical position signals,and the fitting formula of the quadrupole component on the beam transverse size and the beam center position as well as their high order term can be figured out.