Orbit reconstruction, correction and monitoring in the ATF2 extraction line

Abstract

The orbit in the ATF2 extraction line has to be accurately controlled to allow orbit and optics corrections to work well downstream. The Final Focus section contains points with large beta function values which amplify incoming beam jitter, and few correctors since the steering is performed using quadrupole movers, and so good orbit stability is required. First experience monitoring the orbit and measuring transfer matrices in the extraction line during the ATF2 commissioning is described, along with relative orbit reconstruction, allowing comparisons with simulations to identify sources of variations