TY - CPAPER AU - Ratner, D.F. AU - Gover, A. AU - Hemsing, E. AU - Marinelli, A. AU - Nause, A. TI - Subradiant Spontaneous Undulator Emission through Collective Suppression of Shot Noise J2 - Proc. of FEL2015 AB - The phenomenon of Dicke's subradiance, in which the collective properties of a system suppress radiation, has received broad interest in atomic physics, but can also be applied to relativistic electron beams. The resulting "quiet" beam generates less spontaneous undulator radiation than emitted even by a random shot noise beam. Quiet beams could have diverse accelerator applications, including lowering power requirements for seeded FELs. Here we present recent experimental observations at the Next Linear Collider Test Accelerator and discuss prospects for pushing the phenomenon to X-ray wavelengths. PB - JACoW CY - Geneva, Switzerland ER -