- Roughness Tolerance Studies for the Undulator Beam Pipe Chamber of LCLS-II We investigate the effect of wall roughness on the wakefield-induced energy variation in the undulator beam pipe of LCLS-II. We find that a wall roughness equivalent to an rms surface slope of 30 mr increases the total induced energy variation within the bunch (due to the resistive wall wake) by a modest 20%. 2 authors · May 1, 2014
