The new PTB angle comparator

Probst, R; Wittekopf, Reiner; Krause, Michael; Dangschat, H.; Ernst, Andreas

doi:10.1088/0957-0233/9/7/009

Cited by 106 publications

(97 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The In order to realize the stage's potential for calibration of profilometers, a high accuracy angular calibration of the stage is required. We have described an experimental method that allows us to have the tilting stage traceable back to the PTB high performance angle comparator WMT 220 34,35 via application of the AC calibrated at the PTB.…”

Section: Discussionmentioning

confidence: 99%

“…17˗19,24,37,39,40,43 The autocollimators are initially calibrated at the PTB using their Heidenhain TM WMT 220 angle comparator. 34,35 The angle comparator utilizes subdivision of a full circle enclosure, which removes the need for an outside angular reference, to establish an angular standard. The ultimate standard measurement uncertainty of the WMT 220 is about 5 nrad.…”

Section: Utm Tilt Stage Characterization With An Autocollimatormentioning

confidence: 99%

“…The tests at the ALS XROL were based on a comparison of the calibration of the autocollimator (AC) obtained with the UTM tilt stage to that of PTB's measured using their high precision angular comparator. 34,35 The tests have demonstrated high performance of the stage and its capability (after additional precision 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.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

View full text Add to dashboard Cite

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.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Utm Tilt Stage Characterization With An Autocollimatormentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

View full text Add to dashboard Cite

show abstract

“…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].…”

Section: Autocollimator Calibration Datamentioning

confidence: 99%

Aperture alignment in autocollimator-based deflectometric profilometers

Geckeler

Artemiev

Barber

et al. 2016

Review of Scientific Instruments

View full text Add to dashboard Cite

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

show abstract

“…the reliability of the instrument readings is not guaranteed at the same level. Indeed today only in exceptionally complex and accurate facilities operating in few National Metrology Institutes in the world can provide angle measurements/calibrations with nanoradian level accuracy [1,2]. The European project "Angles" [3] is devoted to develop instruments methods and guidelines to improve the accuracy of angle measurements in various application field.…”

Section: Introductionmentioning

confidence: 99%