Beam Jitter Studies at ATF and ATF2

The Accelerator Test Facility (ATF and ATF2) aims to verify key concepts and develop and\nimprove novel technologies for future linear accelerators. One of these key concepts is the\nfocusing of particle beams to extremely small sizes and at the same time achieving very tight\ntolerances of the transversal beam motion. The reduction of the beam motion, especially pulse-topulse\njitter, is therefore of essential importance for the ATF project. Recent measurements show a\ncurrent beam jitter level of about 10% to 20%, which has to be reduced to below 5%. In this\nwork, beam position measurements are used for correlation studies and frequency domain\nanalysis to locate possible beam jitter sources in the damping ring and the ATF2 beam line. As a\nresult of these studies several possible jitter sources have been identified and their individual\nimportance with respect to the overall beam jitter has been quantified. Also the performance of\nthe already operating orbit feedback systems in the damping ring and the ATF2 beam line has\nbeen assessed and suggestions for possible improvements are made. A future inspection of the\nidentified potential jitter sources as well as a refinement of the operating orbit feedback systems\nwith the made suggestions will help to achieve the ultimate beam jitter objectives of ATF2.