Noninvasive beam position, size, divergence and energy diagnostics using diffraction radiation

We have developed non-invasive methods to measure the size, position, divergence and energy of a relativistic charged particle beam using diffraction radiation (DR). The DR is produced by the interaction of the beam fields with single or multiple apertures inclined at an angle of 45 deg. with respect to the beam velocity, {nu}. We propose to utilize the near field image, far field angular distribution (AD) and polarization of backward DR, observed at 90 deg. with respect to {nu}, to diagnose the beam. Unlike transition radiation (TR), the AD of DR is generally a function of the beam's transverse size, {rho} and position of the centroid relative to the center of the aperture, b as well as the divergence, s and energy, E. We show how the effects of {rho} and b on the AD can be minimized or maximized by proper choice of the ratio: R=a/{gamma}{lambda}, where a is the distance from the edge of the aperture to the center of the beam, {lambda}={lambda}/2{pi},{lambda} is the observed wavelength and {gamma} is the Lorentz factor. For example, when R