A great majority of the Advanced Photon Source (APS) users have chosen an u
ndulator as the only source for their insertion device beamline. Compared w
ith a wiggler source, the undulator source has a much smaller horizontal di
vergence, providing us with an opportunity to optimize the beamline front-e
nd design further. In this paper, the particular designs and specifications
, as well as the optical and bremsstrahlung ray-tracing analysis of the new
APS front ends for undulator-only operation are presented. (C) 2001 Elsevi
er Science B.V. All rights reserved.