Spatial and temporal diagnostics of a high-brightness electron beam by technique of laser Thomson scattering

A technique of spatial and temporal diagnostics of an electron beam was investigated experimentally by Thomson scattering of the electron beam with a femtosecond laser beam at a 90° configuration. The spatial structure of the electron beam was measured by scanning the laser across the electron beam in the Thomson scattering, and compared with imaging of the beam profile on a phosphor screen using a charge coupled device. By scanning the femtosecond laser beam in time along the electron beam, we measured the temporal density distributions of short and long electron bunches which were produced in a photocathode rf gun with laser injection phases of 30° and 55°. A subpicosecond time slice of the actual electron beam was achieved in the measurement.