Corrugated pipe as a beam dechirper

We have studied the use of a metallic pipe with small corrugations for the purpose of passively dechirping, through its wakefield, a short, intense electron bunch. The corrugated pipe is attractive for this purpose because its wake: (i) has near maximal possible amplitude for a given aperture and (ii) has a relatively large oscillation wavelength, even when the aperture is small. We showed how the corrugated structure can satisfy dechirping requirements encountered in the NGLS project at LBNL [1]. We found that a linear chirp of −40MeV/mm can be induced by an NGLS-like beam, by having it pass through a corrugated, metallic pipe of radius 3mm, length 8.2m, and corrugation parameters full depth 450μm and period 1000μm. This structure is about 15 times as effective in the role of dechirper as an S-band accelerator structure used passively.