ANL, Lemont, Illinois, USA
As part of the Advanced Photon Source Upgrade (APS-U) project, the Coherent Surface Scattering Imaging (CSSI) [1] instrument is currently being developed. One of the most important components of the CSSI instrument at the 9-ID beamline of the APS-U, the Kirkpatrick-Baez (K-B) mirror system, will focus hard X-rays to a diffrac-tion-limited size of 500 nanometers at a working distance of 550 mm. High angular stability (19 nrad for the hori-zontal mirror and 14 nrad for the vertical mirror) is speci-fied no just for the focused beamsize but, more important-ly, to ensure the beam stability at the detector position that is up to 24 m from the K-B mirrors. A large sample-to-detector distance (up to 23 m), one of the beamline’s unique features for achieving a sufficient coherent-imaging spatial oversampling, requires sample angular stability of 50 nrad. In CSSI scattering geometry, the vertically placed sample reflects X-rays in the horizontal direction at an extremely shallow angle. The design in-cludes two high-precision rotary stages for sample pitch (vertical axis) and yaw (horizontal axis). The current design of instrument’s nano-positioning stages [2] and metrology required to satisfy the stability and positioning requirements are discussed in this paper.
*T. Sun et al., Nat. Photonics 6, 586 (2012).
**D. Shu et al., this conference.
ANL, Lemont, Illinois, USA
Kirkpatrick and Baez (K-B) mirror-based nanofocusing optics* will be applied to many beamlines endstation instruments for the APS-Upgrade (APS-U) project. Precision nanopositioning stages with nanometer-scale linear positioning resolution and nanoradian-scale angular stability are needed as alignment apparatus for the K-B mirror hard X-ray nanofocusing optics. For instance, at the APS-U 19-ID In Situ Nanoprobe beamline endstation**, to maintain stability of a 20-nm focal spot on the sample, nanofocusing K-B mirror system with 5-nrad angular stability is required. Similar angular resolution and stability are also required for APS-U 9-ID CSSI***, APS-U 34-ID ATOMIC**** and other beamline endstation instruments. Modular nanopositioning flexure stages have been developed for the K-B mirror nanofocusing optics, which includes: linear vertical and horizontal flexure stages, tip-tilting flexure stages, and flexure mirror benders for bendable nanofocusing K-B mirrors, to overcome the performance limitations of precision ball-bearing-based or roller-bearing-based stage systems. The mechanical design and preliminary test results are described in this paper.
* Kirkpartrick and Baez, JOSA. 1948; 38(9): 766-773.
** S. Kearney et al., this conference.
*** J. Anton et al., this conference.
**** C. Preissner et al., this conference.