STUDIES OF HIGH HARMONICS BROADENED SPECTRUM UNDULATORS

This study suppresses effectively some unwanted harmonics and broadens the preferred harmonics by introducing a periodic gap between undulat ors and properly selecting the gap size. This effect is ascribed to th e interference between each part of the separated undulator. Closely e xamining the envelop term (i.e. the diffraction term in the case of a grating) of the undulator radiation spectrum reveals the possibility o f this energy redistribution. Analytical results and numerical results are presented to confirm the idea. (C) 1998 Elsevier Science B.V. All rights reserved.