学术报告：A Lattice Correction Approach Through Betatron Phase Advance
报告题目：A Lattice Correction Approach Through Betatron Phase Advance
Most lattice correction algorithms, such as LOCO, use beta function to characterize the lattice. Beta function is usually measured from the amplitude of a BPM signal. It is difficult and time-consuming to calibrate the BPMs precisely in terms of the gain and tilt error. On the other hand, betatron phase is equivalent to beta function and can be obtained from the turn-by-turn BPM signal. The measured phase is not affected by the BPM gain and tilt error. At NSLS-II it was found that the measurement precision of the phase is 1mr, which corresponds to 0.25% beta beat. The phase error can be corrected similarly using a response matrix, and a 5mr (rms) residual phase error can be achieved on the NSLS-II storage ring within half-an-hour. This high precision algorithm can be applied to other measurements, such as calibration of sextupoles and local impedances. A brief introduction to NSLS-II and the recent activities will be presented as well.
W. Guo obtained his Ph.D. in accelerator physics from Indiana University in 2003. He worked at Advanced Photon Source in Chicago from 2003 to 2006, where he proposed a method to generated pico-second short pulses in 3rd generation light sources. From 2006 to present he participated in the design, construction and commissioning of the accelerators of the NSLS-II project. His expertise is mostly linear and nonlinear beam dynamics.