Comparison of angle standards with the aid of a high-resolution angle encoder

Just, A.; Krause, Michael; Probst, R; Bosse, Harald; Haunerdinger, H; Spaeth, C.; Metz, G; Israel, W.

doi:10.1016/j.precisioneng.2009.02.004

Cited by 51 publications

(38 citation statements)

References 6 publications

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“…At the PTB, autocollimator calibration is realized by its direct comparison to the primary angle standard, the Heidenhain WMT 220 angle comparator, manufactured by Dr. Johannes Heidenhain GmbH, Traunreut, Germany [26]. With the aid of various selfand cross-calibration techniques, the standard measurement uncertainty [27] of the WMT 220 could be reduced to u = 0.001 arcsec (5 nrad) [28,29]. With highly stable autocollimators, calibrations with standard uncertainties down to u = 0.003 arcsec (15 nrad) [11,16,17,25] have been achieved.…”

Section: Autocollimator Calibration Datamentioning

confidence: 99%

Aperture alignment in autocollimator-based deflectometric profilometers

Geckeler

Artemiev

Barber

et al. 2016

Review of Scientific Instruments

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Abstract. During the last ten years, deflectometric profilometers have become indispensible tools for the precision form measurement of optical surfaces. They have proven to be especially suitable for characterising beam-shaping optical surfaces for x-ray beamline applications at synchrotrons and Free Electron Lasers. Deflectometric profilometers use surface slope (angle) to assess topography and utilise commercial autocollimators for the contactless slope measurement. To this purpose, the autocollimator beam is deflected by a movable optical square (or pentaprism) towards the surface where a co-moving aperture limits and defines the beam footprint. In this paper, we focus on the precise and reproducible alignment of the aperture relative to the autocollimator's optical axis. Its alignment needs to be maintained while it is scanned across the surface under test. The reproducibility of the autocollimator's measuring conditions during calibration and during its use in the profilometer is of crucial importance to providing precise and traceable angle metrology. In the first part of the paper, we present the aperture alignment procedure developed at the Advanced Light Source, Lawrence Berkeley National Laboratory, USA, for use with their deflectometric profilometers. In the second part, we investigate the topic further by providing extensive ray tracing simulations and calibrations of a commercial autocollimator performed at the Physikalisch-Technische Bundesanstalt, Germany, for evaluating the effects of the positioning of the aperture on the autocollimator's angle response. The investigations which we performed are crucial for reaching fundamental metrological limits in deflectometric profilometry.Keywords: Deflectometry, profilometry, x-ray optics, synchrotron metrology, autocollimator, alignment, calibration, surface slope metrology 1 This research was performed while N. A. Artemiev was at

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Section: Autocollimator Calibration Datamentioning

confidence: 99%

Aperture alignment in autocollimator-based deflectometric profilometers

Geckeler

Artemiev

Barber

et al. 2016

Review of Scientific Instruments

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“…The ultimate standard measurement uncertainty of the WMT 220 is about 5 nrad. 46 In spite of the high precision of the calibration in Fig. 5, maintaining the traceability of the autocollimator to the PTB standard when used in an experimental arrangement and conditions like those at the ALS XROL, different from those during the PTB calibration, is an ongoing pursuit.…”

Section: Utm Tilt Stage Characterization With An Autocollimatormentioning

confidence: 99%

High precision tilt stage as a key element to a universal test mirror for characterization and calibration of slope measuring instruments

Yashchuk

Artemiev

Centers

et al. 2016

Review of Scientific Instruments

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The ultimate performance of surface slope metrology instrumentation, such as long trace profilers and autocollimator based deflectometers, is limited by systematic errors that are increased when the entire angular range is used for metrology of significantly curved optics. At the ALS X-Ray Optics Laboratory, in collaboration with the HZB/BESSY-II and PTB (Germany) metrology teams, we are working on a calibration method for deflectometers, based on a concept of a universal test mirror (UTM) [Proc. SPIE 6704, 67040A (2007)]. Potentially, the UTM method provides high performance calibration, and accounts for peculiarities of the optics under test (e.g., slope distribution) and the experimental arrangement (e.g., the distance between the sensor and the optic under test). At the same time, the UTM calibration method is inherently universal, applicable to a variety of optics and experimental arrangements. In this work we present the results of tests with a key component of the UTM system, a custom high precision tilt stage, which has been recently developed in collaboration with Physik Instrumente, a Author to whom correspondence should be addressed. Electronic mail: VVYashchuk@lbl.gov. 2GmbH. The tests have demonstrated high performance of the stage and its capability (after additional calibration) to provide angular calibration of surface slope measuring profilers over the entire instrumental dynamic range with absolute accuracy better than 30 nrad. The details of the stage design and tests are presented. We also discuss the foundation of the UTM method and calibration algorithm, as well as the possible design of a full scale UTM system.

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“…Accurate angle measure technologies are required in various precision engineering applications, e.g., manufacturing, robotics [1,2]. Indexing tables generate accurate angular positions, and their calibrations are important to ensure high accuracy and reliability in angle metrology [3].…”

Section: Introductionmentioning

confidence: 99%

Calibration of an Indexing Table Using a High Precision Angle Comparator

et al. 2017

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Abstract. The calibration of indexing table is important to ensure high accuracy and reliability in angle metrology. In this paper, we present calibrations of an indexing table and uncertainty analysis to evaluate the performance of the high precision angle comparator. The configuration of the angle comparator is explained. In the calibration, a complete closure method is applied to obtain the angle comparator's position error and the indexing table's angular deviation simultaneously based on the least square method. The position error of the angle comparator is evaluated to be about 0.08". The calibration result of an indexing table is compatible with that of the manufacturer and National Institute of Metrology of China within the expanded uncertainty of calibration, 0.04".

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Comparison of angle standards with the aid of a high-resolution angle encoder

Cited by 51 publications

References 6 publications

Aperture alignment in autocollimator-based deflectometric profilometers

Aperture alignment in autocollimator-based deflectometric profilometers

High precision tilt stage as a key element to a universal test mirror for characterization and calibration of slope measuring instruments

Calibration of an Indexing Table Using a High Precision Angle Comparator

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