Linear Collider Test Facility: Twiss Parameter Analysis at the Ip/post-ip Location of the Atf2 Beam Line *

At the first stage of the ATF2 beam tuning, vertical beam size is usually bigger than 3!m at the IP. Beam waist measurements using wire scanners and a laser wire are usually performed to check the initial matching of the beam through to the IP. These measurements are described in this paper for the optics currently used ("x=4cm and "y=1mm). Software implemented in the control room to automate these measurements with integrated analysis is also described. Measurements showed that " functions and emittances were within errors of measurements when no rematching and coupling corrections were done. However, it was observed that the waist in the horizontal (X) and vertical (Y) plane was abnormally shifted and simulations were performed to try to understand these shifts. They also showed that multiknobs are needed in the current optics to correct simultaneously #x, #y and the horizontal dispersion (Dx). Such multiknobs were found and their linearity and orthogonality were successfully checked using MAD optics code. The software for these multiknobs was implemented in the control room and waist scan measurements using the #y knob were successfully performed.