Ultra-precise characterization of LCLS hard X-ray focusing mirrors by high resolution slope measuring deflectometry

ArticleinOptics Express 20(4):4525-36 · February 2012with35 Reads
Impact Factor: 3.49 · DOI: 10.1364/OE.20.004525 · Source: PubMed

    Abstract

    We present recent results on the inspection of a first diffraction-limited hard X-ray Kirkpatrick-Baez (KB) mirror pair for the Coherent X-ray Imaging (CXI) instrument at the Linac Coherent Light Source (LCLS). The full KB system - mirrors and holders - was under inspection by use of high resolution slope measuring deflectometry. The tests confirmed that KB mirrors of 350mm aperture length characterized by an outstanding residual figure error of <1 nm rms has been realized. This corresponds to the residual figure slope error of about 0.05µrad rms, unprecedented on such long elliptical mirrors. Additional measurements show the clamping of the mirrors to be a critical step for the final - shape preserving installation of such outstanding optics.