OBSERVATION OF COHERENT SYNCHROTRON RADIATION AT THE CORNELL LINAC

The behavior of the far infrared radiation produced by the passage of a mm long bunch of electrons through a vertical 0.44 T magnetic field is found to be consistent with the properties expected for coherent synchrotron radiation. The radiation intensity is proportional to the square of the number of electrons in the bunch. Averaged over the entire spectral bandwidth, the radiation is 82% polarized in the orbit bending plane. A novel metal mesh and hole filter spectrometer is used to determine that most of the radiation appears at wavelengths longer than 1 mm but our observation of shorter wavelength radiation suggests either a non-Gaussian bunch shape or a Gaussian with a submillimeter bunch length.