APPARATUS FOR AMPLIFYING MICROBUNCHING INSTABILITIES OF ELECTRONS

摘要

The invention relates to an apparatus (1) for amplifying space-charge-driven microbunching instabilities of electrons for producing coherent synchrotron radiation in the extreme ultraviolet wavelength range. Here, the apparatus is provided as a constituent part of an accelerator machine. The apparatus comprises a first arrangement of magnets (10) for beam focusing, said first arrangement of magnets being arranged along a first direction (X). This first arrangement comprises a sequence of at least two multipoles (12) of the second order or higher that are arranged in succession along the first direction (X), wherein one multipole (12) has a focusing embodiment and the other has a defocusing embodiment. The beam cross section (σ_tra) lies in the first arrangement in the region of (Formula (I)), where λ = wavelength of the microbunching of the electrons and = γ Lorentz factor. The apparatus further comprises a second arrangement of magnets (40) which serve to convert the energy modulations into density modulations. It comprises a sequence of a plurality of groups (22) of dipoles (24) with different polarity that are arranged along the first direction (X), and a multipole (50), at least of second order, which precedes the dipoles. An input beta function is increased by at least a factor of four in the second arrangement.