Shu, D. Anton, J.W.J. Assoufid, L. Bean, S.J. Capatina, D. De Andrade, V. Dufresne, E.M. Graber, T. Harder, R. Haskel, D. Jasionowski, K. Kearney, S.P. Khan, A.A. Lai, B. Liu, W. Maser, J. Mashrafi, S.T. Mistri, G.K. Narayanan, S. Preissner, C.A. Ramanathan, M. Rebuffi, L. Reininger, R. Schmidt, O.A. Shi, X. Tischler, J.Z. Wakefield, K.J. Walko, D. Wang, J. Zhang, X. JACoW Publishing Geneva, Switzerland 2673-5520 978-3-95450-229-5 10.18429/JACoW-MEDSI2020-TUPC10 English 199-202 focusing optics alignment photon synchrotron Contribution to a conference proceedings 2021 2021-10 https://doi.org/10.18429/JACoW-MEDSI2020-TUPC10 https://jacow.org/medsi2020/papers/tupc10.pdf 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.