Beam Tilt Signals as Emittance Diagnostic in the Next Linear Collider Main Linac

High frequency cavity beam position monitors (BPMs) can also provide information on the xz or yz correlation of the beam (yaw or pitch, respectively). Such a diagnostic is particularly desirable in the Next Linear Collider (NLC) main linacs, where the principal sources of emittance dilution generate such a correlation. Test results from the extremely low emittance beam at the KEK Accelerator Test Facility (ATF) (1) are described. The formalism of beam-tilt signal generation and detection are reviewed, and studies of possible emittance correction schemes based on the beam tilt signals are presented.