Zhu, Y. Hulbert, S. Idir, M. Jarrige, I. O'Hara, S. Vescovo, E. JACoW Publishing Geneva, Switzerland 978-3-95450-207-3 10.18429/JACoW-MEDSI2018-FROAMA05 English 435-439 FROAMA05 photon optics diagnostics MMI electron Contribution to a conference proceedings 2018 2018-12 https://doi.org/10.18429/JACoW-MEDSI2018-FROAMA05 http://jacow.org/medsi2018/papers/froama05.pdf Two of the five NSLS-II Experimental Tools (NEXT) project insertion-device beamlines developed for the NSLS-II facility at Brookhaven National Laboratory are state-of-the-art soft X-ray beamlines covering the 15 eV- 1500 eV photon energy range. The engineering challenges of these two beamlines included: accurate and realistic optical simulations, nearly perfect optic figure and mechanical/thermal implementation, and advanced diagnostics systems developed in-house. The measured performance (flux, spot size, resolution) of these two beamlines closely matches the calculated values. Here, the engineering design and performance measurements of these two beamlines are presented.