为了测量和校正线性光学参数,在上海光源储存环调束过程当中使用了基于响应矩阵的线性光学参数分析(LOCO)的方法。介绍了应用LOCO进行计算和校正的过程,包括:数值模拟得到束流位置探测器的测量精度对拟合结果的影响,调整四极铁电源电流强度来校正工作点和beta函数周期性的恢复。测量结果表明,在四极铁强度调整幅度在1.5%以内的情况下,储存环的束流光学参数成功地恢复到和设计值相当接近的状态,beta函数和色散函数畸变小于1%。通过束流光学参数的校正,使得在今后的工作当中可以轻松地控制储存环的工作模式。

Linear optics from closed orbits (LOCO) has been used during the commissioning of the Shanghai Synchrotron Radiation Facility (SSRF) storage ring. The LOCO compares a model response matrix to the real machine response matrix. Using the measured response matrix of the SSRF storage ring,the gradients in all 200 quadrupole magnets were determined,and the calibration factors of steering magnets and beam position monitors (BPMs) were obtained at the same time. After adjusting the currents of quadrupole-magnet power supplies by the maximum of 1.5%,the optics parameters were restored very close to the designed values. The horizontal and vertical differences of beta function from the design values are around 10% before correction and 1% after correction.