Feasibility of optical diffraction radiation for a non-invasive low-emittance beam diagnostics

A "proof-of-principle" experiment on the optical diffraction radiation (ODR ) as a single-pulse beam profile monitor is planned using an electron beam extracted from the KEK-ATF damping ring. The main goals of this experiment are the following: (i) To measure the yield and the angular distributions of the optical diffr action radiation from a large-size target at different wavelengths, impact parameters and beam characteristics for a comparison with analogous charact eristics of optical transition radiation from a foil with identical optical parameters and for a verification of the model assumption (perfectly condu cting semi-infinite target). (ii) To investigate the ODR angular distributions from a tilted target with a slit for observing the interference effects. (iii) To compare the results obtained by simulations based on classical app roaches, taking into account the optical characteristics of the equipment a nd the beam parameters. (iv) To estimate the prospects of using ODR as a new non-invasive tool for ultrarelativistic beams. We estimated that the ODR photon yield in 10% bandwidth for 500 nm is about 10(6) photons/bunch with an impact parameter of 100 pm. This indicates tha t the ODR monitor is a promising candidate for single-pulse beam-profile me asurements, and that it will be an extremely useful instrument for future l inear colliders (JLC, NLC, TESLA and CLIC). (C) 2001 Elsevier Science B.V. All rights reserved.