Coherent transition and diffraction radiation from a bunched 6.1Â MeV electron beam

The intensity of CBTR and CBDR from a finite conducting target for different impact-parameters depending on the target inclination angle θ (θ-scan) has been investigated using the 6 MeV electron beam of the Tomsk microtron. The model allowing to calculate both TR and DR characteristics for any impact-parameter h (the shortest distance between particle trajectory and target edge) was developed and tested by comparison with experimental results. The calculations were performed for the real experimental conditions. For γλ ≫ h (γ - Lorentz-factor, λ - TR (DR) wavelength) and large detector bandwidth γ(λmax-λmin)h>1 the measured TR angular distribution shows a single maximum only (like DR one) in contrast to a lobe-shaped OTR distribution.