2020同步年報

096 ACTIVITY REPORT 2020 [U S V] = svd( M ) (1) ∆I = V*(diag(diag( S ). -1 )*( U .'*∆ν)) (2) Tune Shift of the Insertion Devices in TPS Figure 2 shows the tune shift caused by six IU moving simultaneously around the minimum gap at beam current 400 mA. The tune shifts are 0.0076 and 0.0087 for the horizontal and vertical planes, respectively. Another observation shows that the tune shifts caused by EPU46 are -0.0025 and 0.0018 for the horizontal and vertical planes, respectively, with the gap of 14 mm and the phase of 23 mm; the tune shifts caused by EPU48B are -0.0045 and 0.0024 for the horizontal and vertical planes, respectively, with gap of 13 mm and phase of 24 mm. Performance of the Global Tune Feedback Figure 3 shows the performance of the global tune feedback. A red vertical dash line indicates the global tune feedback on and off. To verify the performance of the global tune feedback in TPS, a machine study was conducted, described as follows. TPS operates in top-up injection mode. The deviations of the horizontal and vertical tune are pronounced with the gap closing of the EPU46 and EPU48B. When the global tune feedback is turned on, the tune deviations are brought back to the target tune. During the variation of the gap/phase of the EPU46 and EPU48B, the tune deviations are well controlled within a tolerance of 0.001 by the global tune feedback. (Reported by Mau-Sen Chiu) References 1. Algorithm of the tune feedback, P. J. Chou (private communication). 2. C. H. Kuo, P. C. Chiu, K. H. Hu, C. Y. Wu, C. Y. Liao, Y. S. Cheng, J. Chen, K. T. Hsu, Proc. IPAC' 11 , MOPO016, 517 (2011). Fig. 3 : The performance of the global tune feedback in TPS.