Vertical Beam Size Control in Tls and Tps

VERTICAL BEAM SIZE CONTROL IN TLS AND TPS C.C. Kuo, J.R. Chen, P.J. Chou, H.P. Chang, K.T. Hsu, G.H. Luo, H.J. Tsai, D.J. Wang, M.H. Wang National Synchrotron Radiation Research Center, Hsinchu, Taiwan A. Chao , SLAC W.T. Weng, BNL Abstract Vertical beam size control is an important issue in the light source operations. The horizontal-vertical betatron coupling and vertical dispersion were measured and corrected to small values in the TLS 1.5 GeV storage ring. Estimated beam sizes are compared with the measured values. By employing an effective transverse damping system, the vertical beam blow-up due to transverse coherent instabilities, such as the fast-ion beam instability, was suppressed. As a result, the light source is very stable. In NSRRC we are designing an ultra low emittance 3-GeV storage ring and its designed vertical beam size could be as small as a few microns. The ground and mechanic vibration effects, and coherent instabilities could spoil the expected photon brightness due to blowup of the vertical beam size if not well taken care of. The contributions of these effects to vertical beam size increase will be evaluated and the counter measures to minimize them will be proposed and reported in this paper.