Measurement of Beam Position Using Highly-Damped Accelerating Structures

Active alignment algorithms for linear colliders such as the Compact LInear Collider (CLIC), require measurements of beam positions inside accelerating structures in order to control short and long-range transverse wakefields. Highly-damped accelerating structures offer the possibility that damping waveguides can provide position signals so the accelerating structure itself can be used to make these position measurements. A demonstration of beam position measurement using a 3GHz slotted iris structure with a dipole mode Q of about 16 was made in CTF II (CLIC Test Facility) and results are compared to computations using HFSS and GdfidL.