北京正负电子对撞机同步辐射光脉冲形状的高分辨率测量

SHAPE MEASUREMENT OF SYNCHROTRON RADIATION WITH HIGH TIME RESOLUTION

用国产BWS-5KII型皮秒扫描相机测量了北京正负电子对撞机(BEPC)上极端相对论性运动正负电子束团产生的同步辐射光脉冲的时间结构、光脉冲长度与电子束流强度以及射频源电压的关系.当负电子束流强度由2mA增加到30mA时,光脉冲长度由220ps增加到670ps;在20mA电子束流强度条件下,射频源电压由250kV增加到500kV时,光脉冲长度在500ps到700ps范围内变化.测量系统的时间分辨率为30ps;时间刻度误差±15％,触发晃动小于±200ps.

By using BWS-5K Ⅱ streak camera made in China, we have measured the time structure of Synchrotron Radiation (SR) from the relativistic electron and positron beam bunches of Beijing Electron Positron Collider (BEPC). The dependence of SR width to the intensity of beam current and the voltage of RF source was also measured. The main data taken with 30ps time resolution in the experiment are as follows: The length of CR at E_e = 1.549 GeV is changed from 220ps to 670ps when the average beam current from 2mA to 30mA, the variation range of CR length at 20mA beam current is 500-700ps with RF source voltage varying between 250kV and 500kV. The time calibration uncertainty of the experiment is ±15%. The trigger jitter is less than±200ps.