根据同步光与储存环中的束流信号具有相同的时间结构的原理,测量同步光脉冲的半高全宽值可以计算出束团的长度。根据合肥光源的特点和实际需要,选择快速光电接收器搭配高速高带宽示波器作为在线测量束团长度和纵向分布等的主要手段。对单束团模式下束团长度随流强和高频腔腔压的变化趋势进行了测量。测量结果表明:束团长度与腔压的0.3次方成反比,比理论值0.5小;而束团长度随流强的增长率为2.0 ps/mA。通过测量纵向量子寿命进行了能散随流强变化的间接测量,结果表明,束团的拉伸是能散变化和势阱效应共同作用的结果。

Based on the principle that the synchrotron light has the same time structure with the beam signal,bunch length can be calculated by measuring the full width half height of the synchrotron light pulse.The variation of bunch length with beam current and RF loltage in single bunch mode was measured.And the result shows that the bunch length is in reverse proportion to the RF voltage to the power of 0.3 and it is smaller than the theoretical result.The growth rate of bunch length with the beam current is 2.0 ps/mA.The energy spread was measured by measuring the longitudinal quantum lifetime,which indicates that the bunch lengthening is the result of energy spread and potential well distortion.