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LSBL Automated suppression of errors in LTP-II slope measurements with x-ray optics. Part1: Review of LTP errors and methods for the error reduction Zulfiqar Ali and Valeriy V. Yashchuk Lawrence Berkeley National Laboratory, Berkeley, California 94720 ABSTRACT Systematic error and instrumental drift are the major limiting factors of sub-microradian slope metrology with state- of-the-art x-ray optics. Significant suppression of the errors can be achieved by using an optimal measurement strategy suggested in [Rev. Sci. Instrum. 80, 115101 (2009)]. With this series of LSBL Notes, we report on development of an automated, kinematic, rotational system that provides fully controlled flipping, tilting, and shifting of a surface under test. The system is integrated into the Advanced Light Source long trace profiler, LTP-II, allowing for complete realization of the advantages of the optimal measurement strategy method. We provide details of the system’s design, operational control and data acquisition. The high performance of the system is demonstrated via the results of high precision measurements with a spherical test mirror. Keywords: surface slope metrology, drift error, systematic error, optimal scanning, metrology of x-ray optics, deflectometry 1. INTRODUCTION Development, characterization, and application of state-of-the-art X-ray optics for 3rd and 4th generation X-ray light sources with a level of surface slope precision of 0.1-0.2 rad requires the development of adequate dedicated metrology instrumentation and methods [1-3]. The best performing slope measuring profilers at synchrotron facilities, such as the Nanometer Optical Component Measuring Machines (NOM) at Helmholtz Zentrum Berlin (HZB)/BESSY-II (Germany) [4-7] and at the Diamond Light Source (UK) [8], as well as Long Trace Profilers (LTP) at SPring-8 (Japan) [9], at ESRF [10,11], at SOLEIL [12,13] (France), and at the ALS (U.S.A.) [14-16] come close to the required precision. The high performance of the instruments is based on thorough suppression of the measurement errors due to random noise, systematic effects, and instrumental drifts. A comprehensive analysis of errors of slope measurements and discussion of methods for decreasing the errors can be found, e.g., in Refs. [16-21]. Significant suppression of the errors (in particular, errors associated with instrumental and set-up drifts) can be achieved by using an optimal measurement strategy suggested and comprehensively analyzed in Ref. [20]. With the present Note, we start reporting on development of an automated, kinematic, rotational system that provides fully controlled flipping, tilting, and shifting of a surface under test. The system is integrated into the Advanced Light Source long trace profiler, LTP-II, allowing for complete realization of the advantages of the optimal measurement strategy method. We start here with analysis of the major contributors to the LTP error budget and a brief discussion of the methods developed to decrease the errors. The optimal measurement (scanning)