WorldWideScience

Sample records for frequency metrology based

  1. Frequency Standards and Metrology

    Science.gov (United States)

    Maleki, Lute

    2009-04-01

    Preface / Lute Maleki -- Symposium history / Jacques Vanier -- Symposium photos -- pt. I. Fundamental physics. Variation of fundamental constants from the big bang to atomic clocks: theory and observations (Invited) / V. V. Flambaum and J. C. Berengut. Alpha-dot or not: comparison of two single atom optical clocks (Invited) / T. Rosenband ... [et al.]. Variation of the fine-structure constant and laser cooling of atomic dysprosium (Invited) / N. A. Leefer ... [et al.]. Measurement of short range forces using cold atoms (Invited) / F. Pereira Dos Santos ... [et al.]. Atom interferometry experiments in fundamental physics (Invited) / S. W. Chiow ... [et al.]. Space science applications of frequency standards and metrology (Invited) / M. Tinto -- pt. II. Frequency & metrology. Quantum metrology with lattice-confined ultracold Sr atoms (Invited) / A. D. Ludlow ... [et al.]. LNE-SYRTE clock ensemble: new [symbol]Rb hyperfine frequency measurement - spectroscopy of [symbol]Hg optical clock transition (Invited) / M. Petersen ... [et al.]. Precise measurements of S-wave scattering phase shifts with a juggling atomic clock (Invited) / S. Gensemer ... [et al.]. Absolute frequency measurement of the [symbol] clock transition (Invited) / M. Chwalla ... [et al.]. The semiclassical stochastic-field/atom interaction problem (Invited) / J. Camparo. Phase and frequency noise metrology (Invited) / E. Rubiola ... [et al.]. Optical spectroscopy of atomic hydrogen for an improved determination of the Rydberg constant / J. L. Flowers ... [et al.] -- pt. III. Clock applications in space. Recent progress on the ACES mission (Invited) / L. Cacciapuoti and C. Salomon. The SAGAS mission (Invited) / P. Wolf. Small mercury microwave ion clock for navigation and radioScience (Invited) / J. D. Prestage ... [et al.]. Astro-comb: revolutionizing precision spectroscopy in astrophysics (Invited) / C. E. Kramer ... [et al.]. High frequency very long baseline interferometry: frequency standards and

  2. Swept Frequency Laser Metrology System

    Science.gov (United States)

    Zhao, Feng (Inventor)

    2010-01-01

    A swept frequency laser ranging system having sub-micron accuracy that employs multiple common-path heterodyne interferometers, one coupled to a calibrated delay-line for use as an absolute reference for the ranging system. An exemplary embodiment uses two laser heterodyne interferometers to create two laser beams at two different frequencies to measure distance and motions of target(s). Heterodyne fringes generated from reflections off a reference fiducial X(sub R) and measurement (or target) fiducial X(sub M) are reflected back and are then detected by photodiodes. The measured phase changes Delta phi(sub R) and Delta phi (sub m) resulting from the laser frequency swept gives target position. The reference delay-line is the only absolute reference needed in the metrology system and this provides an ultra-stable reference and simple/economical system.

  3. Terahertz frequency metrology based on high-T sub c Josephson junctions

    CERN Document Server

    Chen, J; Wang, H B; Nakajima, K; Yamashita, T; Wu, P H

    2002-01-01

    Using YBa sub 2 Cu sub 3 O sub 7 /MgO bicrystal Josephson junctions operating between 6-77 K, we have studied their responses to monochromatic electromagnetic radiation from 50 GHz to 4.25 THz. We have obtained direct detections for radiation at 70 K from 50 GHz to 760 GHz and at 40 K from 300 GHz to 3.1 THz. This indicates that fast detectors can be realized to cover the 10:1 frequency band at one operation temperature, and about 100:1 can be covered by operating only one junction at two different temperatures. Both the highest response frequency and the maximum value of the normalized response are shown to be proportional to the I sub C R sub N product of the junction, where I sub C and R sub N are the critical current and the normal resistance of the junction, respectively.

  4. New approaches in diffraction based optical metrology

    Science.gov (United States)

    Ebert, M.; Vanoppen, P.; Jak, M.; v. d. Zouw, G.; Cramer, H.; Nooitgedagt, T.; v. d. Laan, H.

    2016-03-01

    Requirements for on-product overlay, focus and CD uniformity continue to tighten in order to support the demands of 10nm and 7nm nodes. This results in the need for simultaneously accurate, robust and dense metrology data as input for closed-loop control solutions thereby enabling wafer-level control and high order corrections. In addition the use of opaque materials and stringent design rules drive the need for expansion of the available measurement wavelengths and metrology target design space. Diffraction based optical metrology has been established as the leading methodology for integrated as well as standalone optical metrology for overlay, focus and CD monitoring and control in state of the art chip manufacturing. We are presenting the new approaches to diffraction based optical metrology designed to meet the processing diffraction based metrology signals. In this paper we will present the new detection principle and its impact on key performance characteristics of overlay and focus measurements. We will also describe the wide range of applications of a newly introduced increased measurement spot size, enabling significant improvements to accuracy and process robustness of overlay and focus measurements. With the YS350E the optical CD measurement capability is also extended, to 10x10μm2 targets. We will discuss the performance and value of small targets in after-develop and after-etch applications.

  5. Frequency metrology using highly charged ions

    Science.gov (United States)

    Crespo López-Urrutia, J. R.

    2016-06-01

    Due to the scaling laws of relativistic fine structure splitting, many forbidden optical transitions appear within the ground state configurations of highly charged ions (HCI). In some hydrogen-like ions, even the hyperfine splitting of the 1s ground state gives rise to optical transitions. Given the very low polarizability of HCI, such laser-accessible transitions are extremely impervious to external perturbations and systematics that limit optical clock performance and arise from AC and DC Stark effects, such as black-body radiation and light shifts. Moreover, AC and DC Zeeman splitting are symmetric due to the much larger relativistic spin-orbit coupling and corresponding fine-structure splitting. Appropriate choice of states or magnetic sub-states with suitable total angular momentum and magnetic quantum numbers can lead to a cancellation of residual quadrupolar shifts. All these properties are very advantageous for the proposed use of HCI forbidden lines as optical frequency standards. Extremely magnified relativistic, quantum electrodynamic, and nuclear size contributions to the binding energies of the optically active electrons make HCI ideal tools for fundamental research, as in proposed studies of a possible time variation of the fine structure constant. Beyond this, HCI that cannot be photoionized by vacuum-ultraviolet photons could also provide frequency standards for future lasers operating in that range.

  6. Frequency metrology in quantum degenerate helium

    Directory of Open Access Journals (Sweden)

    Vassen Wim

    2013-08-01

    Full Text Available We have measured the absolute frequency of the 1557-nm doubly forbidden transition between the two metastable states of helium, 2 3S1 (lifetime 8000 s and 2 1S0 (lifetime 20 ms, with 1 kHz precision. With an Einstein coefficient of 10−7 s−1 this is one of weakest optical transitions ever measured. The measurement was performed in a Bose-Einstein condensate of 4He* as well as in a Degenerate Fermi Gas of 3He*, trapped in a crossed dipole trap. From the isotope shift we deduced the nuclear charge radius difference between the α-particle and the helion. Our value differs by 4σ with a very recent result obtained on the 2 3S → 2 3P transition.

  7. Frequency comb metrology with an optical parametric oscillator.

    Science.gov (United States)

    Balskus, K; Schilt, S; Wittwer, V J; Brochard, P; Ploetzing, T; Jornod, N; McCracken, R A; Zhang, Z; Bartels, A; Reid, D T; Südmeyer, T

    2016-04-18

    We report on the first demonstration of absolute frequency comb metrology with an optical parametric oscillator (OPO) frequency comb. The synchronously-pumped OPO operated in the 1.5-µm spectral region and was referenced to an H-maser atomic clock. Using different techniques, we thoroughly characterized the frequency noise power spectral density (PSD) of the repetition rate frep, of the carrier-envelope offset frequency fCEO, and of an optical comb line νN. The comb mode optical linewidth at 1557 nm was determined to be ~70 kHz for an observation time of 1 s from the measured frequency noise PSD, and was limited by the stability of the microwave frequency standard available for the stabilization of the comb repetition rate. We achieved a tight lock of the carrier envelope offset frequency with only ~300 mrad residual integrated phase noise, which makes its contribution to the optical linewidth negligible. The OPO comb was used to measure the absolute optical frequency of a near-infrared laser whose second-harmonic component was locked to the F = 2→3 transition of the 87Rb D2 line at 780 nm, leading to a measured transition frequency of νRb = 384,228,115,346 ± 16 kHz. We performed the same measurement with a commercial fiber-laser comb operating in the 1.5-µm region. Both the OPO comb and the commercial fiber comb achieved similar performance. The measurement accuracy was limited by interferometric noise in the fibered setup of the Rb-stabilized laser.

  8. Advanced applications of scatterometry based optical metrology

    Science.gov (United States)

    Dixit, Dhairya; Keller, Nick; Kagalwala, Taher; Recchia, Fiona; Lifshitz, Yevgeny; Elia, Alexander; Todi, Vinit; Fronheiser, Jody; Vaid, Alok

    2017-03-01

    The semiconductor industry continues to drive patterning solutions that enable devices with higher memory storage capacity, faster computing performance, and lower cost per transistor. These developments in the field of semiconductor manufacturing along with the overall minimization of the size of transistors require continuous development of metrology tools used for characterization of these complex 3D device architectures. Optical scatterometry or optical critical dimension (OCD) is one of the most prevalent inline metrology techniques in semiconductor manufacturing because it is a quick, precise and non-destructive metrology technique. However, at present OCD is predominantly used to measure the feature dimensions such as line-width, height, side-wall angle, etc. of the patterned nano structures. Use of optical scatterometry for characterizing defects such as pitch-walking, overlay, line edge roughness, etc. is fairly limited. Inspection of process induced abnormalities is a fundamental part of process yield improvement. It provides process engineers with important information about process errors, and consequently helps optimize materials and process parameters. Scatterometry is an averaging technique and extending it to measure the position of local process induced defectivity and feature-to-feature variation is extremely challenging. This report is an overview of applications and benefits of using optical scatterometry for characterizing defects such as pitch-walking, overlay and fin bending for advanced technology nodes beyond 7nm. Currently, the optical scatterometry is based on conventional spectroscopic ellipsometry and spectroscopic reflectometry measurements, but generalized ellipsometry or Mueller matrix spectroscopic ellipsometry data provides important, additional information about complex structures that exhibit anisotropy and depolarization effects. In addition the symmetry-antisymmetry properties associated with Mueller matrix (MM) elements

  9. Operation of an optically coherent frequency comb outside the metrology lab

    CERN Document Server

    Sinclair, Laura C; Swann, William C; Rieker, Greg B; Hati, Archita; Iwakuni, Kana; Newbury, Nathan R

    2013-01-01

    We demonstrate a self-referenced fiber frequency comb that can operate outside the well-controlled optical laboratory. The frequency comb has residual optical linewidths of < 1 Hz, sub-radian residual optical phase noise, and residual pulse-to-pulse timing jitter of 2.4 - 5 fs, when locked to an optical reference. This fully phase-locked frequency comb has been successfully operated in a moving vehicle with 0.5 g peak accelerations and on a shaker table with a sustained 0.5 g rms integrated acceleration, while retaining its optical coherence and 5-fs-level timing jitter. This frequency comb should enable metrological measurements outside the laboratory with the precision and accuracy that are the hallmarks of comb-based systems. Work of the U.S. government, not subject to copyright

  10. Operation of an optically coherent frequency comb outside the metrology lab.

    Science.gov (United States)

    Sinclair, L C; Coddington, I; Swann, W C; Rieker, G B; Hati, A; Iwakuni, K; Newbury, N R

    2014-03-24

    We demonstrate a self-referenced fiber frequency comb that can operate outside the well-controlled optical laboratory. The frequency comb has residual optical linewidths of < 1 Hz, sub-radian residual optical phase noise, and residual pulse-to-pulse timing jitter of 2.4 - 5 fs, when locked to an optical reference. This fully phase-locked frequency comb has been successfully operated in a moving vehicle with 0.5 g peak accelerations and on a shaker table with a sustained 0.5 g rms integrated acceleration, while retaining its optical coherence and 5-fs-level timing jitter. This frequency comb should enable metrological measurements outside the laboratory with the precision and accuracy that are the hallmarks of comb-based systems.

  11. Whispering gallery mode resonators for frequency metrology applications

    Science.gov (United States)

    Baumgartel, Lukas

    This dissertation describes an investigation into the use of whispering gallery mode (WGM) resonators for applications towards frequency reference and metrology. Laser stabilization and the measurement of optical frequencies have enabled myriad technologies of both academic and commercial interest. A technology which seems to span both motivations is optical atomic clocks. These devices are virtually unimaginable without the ultra stable lasers plus frequency measurement and down-conversion afforded by Fabry Perot (FP) cavities and model-locked laser combs, respectively. However, WGM resonators can potentially perform both of these tasks while having the distinct advantages of compactness and simplicity. This work represents progress towards understanding and mitigating the performance limitations of WGM cavities for such applications. A system for laser frequency stabilization to a the cavity via the Pound-Drever-Hall (PDH) method is described. While the laser lock itself is found to perform at the level of several parts in 1015, a variety of fundamental and technical mechanisms destabilize the WGM frequency itself. Owing to the relatively large thermal expansion coefficients in optical crystals, environmental temperature drifts set the stability limit at time scales greater than the thermal relaxation time of the crystal. Uncompensated, these drifts pull WGM frequencies about 3 orders of magnitude more than they would in an FP cavity. Thus, two temperature compensation schemes are developed. An active scheme measures and stabilizes the mode volume temperature to the level of several nK, reducing the effective temperature coefficient of the resonator to 1.7x10-7 K-1; simulations suggest that the value could eventually be as low as 3.5x10-8 K-1, on par with the aforementioned FP cavities. A second, passive scheme is also described, which employs a heterogeneous resonator structure that capitalizes on the thermo-mechanical properties of one material and the optical

  12. Advanced overlay analysis through design based metrology

    Science.gov (United States)

    Ji, Sunkeun; Yoo, Gyun; Jo, Gyoyeon; Kang, Hyunwoo; Park, Minwoo; Kim, Jungchan; Park, Chanha; Yang, Hyunjo; Yim, Donggyu; Maruyama, Kotaro; Park, Byungjun; Yamamoto, Masahiro

    2015-03-01

    As design rule shrink, overlay has been critical factor for semiconductor manufacturing. However, the overlay error which is determined by a conventional measurement with an overlay mark based on IBO and DBO often does not represent the physical placement error in the cell area. The mismatch may arise from the size or pitch difference between the overlay mark and the cell pattern. Pattern distortion caused by etching or CMP also can be a source of the mismatch. In 2014, we have demonstrated that method of overlay measurement in the cell area by using DBM (Design Based Metrology) tool has more accurate overlay value than conventional method by using an overlay mark. We have verified the reproducibility by measuring repeatable patterns in the cell area, and also demonstrated the reliability by comparing with CD-SEM data. We have focused overlay mismatching between overlay mark and cell area until now, further more we have concerned with the cell area having different pattern density and etch loading. There appears a phenomenon which has different overlay values on the cells with diverse patterning environment. In this paper, the overlay error was investigated from cell edge to center. For this experiment, we have verified several critical layers in DRAM by using improved(Better resolution and speed) DBM tool, NGR3520.

  13. High-precision, wavelength flexible frequency division for metrology

    NARCIS (Netherlands)

    Gross, Petra; Klein, Marvin E.; Boller, Klaus-Jochen

    2005-01-01

    We realize and investigate wavelength-flexible phase-coherent all-optical frequency division by 2. Frequency division is obtained via self-phase-locking in a degenerate continuous-wave (cw) optical parametric oscillator (OPO). The wavelength flexibility of the divider is based on the use of quasi-ph

  14. In-field Raman amplification on coherent optical fiber links for frequency metrology.

    Science.gov (United States)

    Clivati, C; Bolognini, G; Calonico, D; Faralli, S; Mura, A; Levi, F

    2015-04-20

    Distributed Raman amplification (DRA) is widely exploited for the transmission of broadband, modulated signals used in data links, but not yet in coherent optical links for frequency metrology, where the requirements are rather different. After preliminary tests on fiber spools, in this paper we deeper investigate Raman amplification on deployed in-field optical metrological links. We actually test a Doppler-stabilized optical link both on a 94 km-long metro-network implementation with multiplexed ITU data channels and on a 180 km-long dedicated fiber haul connecting two cities, where DRA is employed in combination with Erbium-doped fiber amplification (EDFA). The performance of DRA is detailed in both experiments, indicating that it does not introduce noticeable penalties for the metrological signal or for the ITU data channels. We hence show that Raman amplification of metrological signals can be compatible with a wavelength division multiplexing architecture and that it can be used as an alternative or in combination with dedicated bidirectional EDFAs. No deterioration is noticed in the coherence properties of the delivered signal, which attains frequency instability at the 10(-19) level in both cases. This study can be of interest also in view of the undergoing deployment of continental fiber networks for frequency metrology.

  15. Frequency and time transfer for metrology and beyond using telecommunication network fibres

    CERN Document Server

    Lopez, Olivier; Jiang, Haifeng; Haboucha, Adil; Bercy, Anthony; Stefani, Fabio; Chanteau, Bruno; Kanj, Amale; Rovera, Daniele; Achkar, Joseph; Chardonnet, Christian; Pottie, Paul-Eric; Amy-Klein, Anne; Santarelli, Giorgio

    2015-01-01

    The distribution and the comparison of an ultra-stable optical frequency and accurate time using optical fibres have been greatly improved in the last ten years. The frequency stability and accuracy of optical links surpass well-established methods using the global navigation satellite system and geostationary satellites. In this paper, we present a review of the methods and the results obtained. We show that public telecommunication network carrying Internet data can be used to compare and distribute ultra-stable metrological signals over long distances. This novel technique paves the way for the deployment of a national and continental ultra-stable metrological optical network.

  16. Lightweight UAV with on-board photogrammetry and single-frequency GPS positioning for metrology applications

    Science.gov (United States)

    Daakir, M.; Pierrot-Deseilligny, M.; Bosser, P.; Pichard, F.; Thom, C.; Rabot, Y.; Martin, O.

    2017-05-01

    This article presents a coupled system consisting of a single-frequency GPS receiver and a light photogrammetric quality camera embedded in an Unmanned Aerial Vehicle (UAV). The aim is to produce high quality data that can be used in metrology applications. The issue of Integrated Sensor Orientation (ISO) of camera poses using only GPS measurements is presented and discussed. The accuracy reached by our system based on sensors developed at the French Mapping Agency (IGN) Opto-Electronics, Instrumentation and Metrology Laboratory (LOEMI) is qualified. These sensors are specially designed for close-range aerial image acquisition with a UAV. Lever-arm calibration and time synchronization are explained and performed to reach maximum accuracy. All processing steps are detailed from data acquisition to quality control of final products. We show that an accuracy of a few centimeters can be reached with this system which uses low-cost UAV and GPS module coupled with the IGN-LOEMI home-made camera.

  17. Web-Based Learning and Training for Virtual Metrology Lab

    CERN Document Server

    Al-Zahrani, Fahad

    2010-01-01

    The use of World Web Wide for distance education has received increasing attention over the past decades. The real challenge of adapting this technology for engineering education and training is to facilitate the laboratory experiments via Internet. In the sciences, measurement plays an important role. The accuracy of the measurement, as well as the units, help scientists to better understand phenomena occurring in nature. This paper introduces Metrology educators to the use and adoption of Java-applets in order to create virtual, online Metrology laboratories for students. These techniques have been used to successfully form a laboratory course which augments the more conventional lectures in concepts of Metrology course at Faculty of Engineering, Albaha University, KSA. Improvements of the package are still undergoing to incorporate Web-based technologies (Internet home page, HTML, Java programming etc...). This Web-based education and training has been successfully class-tested within an undergraduate prel...

  18. Electromagnetic Nanoscale Metrology Based on Entropy Production and Fluctuations

    Directory of Open Access Journals (Sweden)

    James Baker-Jarvis

    2008-10-01

    Full Text Available The goal in this paper is to show how many high-frequency electromagnetic metrology areas can be understood and formulated in terms of entropy evolution, production, and fluctuations. This may be important in nanotechnology where an understanding of fluctuations of thermal and electromagnetic energy and the effects of nonequilibrium are particularly important. The approach used here is based on a new derivation of an entropy evolution equation using an exact Liouville-based statistical-mechanical theory rooted in the Robertson-Zwanzig-Mori formulations. The analysis begins by developing an exact equation for entropy rate in terms of time correlations of the microscopic entropy rate. This equation is an exact fluctuation-dissipation relationship. We then define the entropy and its production for electromagnetic driving, both in the time and frequency domains, and apply this to study dielectric and magnetic material measurements, magnetic relaxation, cavity resonance, noise, measuring Boltzmann’s constant, and power measurements.

  19. Metrological analysis of type MTs-3 cesium frequency reference

    Energy Technology Data Exchange (ETDEWEB)

    Abashev, Y.G.; Baryshev, V.N.; Elkin, G.A.; Polyakova, L.I.; Pushkin, S.B.; TimoFeev, Y.V.

    1986-07-01

    This paper describes the type MTs-3 atomic-beam system whichhas a bipolar sorting magnet and a transverse, uniform magnetic field that is created by a system of four rods. A multichannel collimator with a cross section of 0.5 x 9 mm is used in the source for the beam of cesium atoms. In order to determine the frequency shift due to phase differences in the resonator provision was made for changing the direction of the atomic beam to the opposite. The MTs-3 was compared with the state frequency standard; results are presented. A comparison of the frequency reproduced by the MTs-3 with the frequencies reproduced by types MTs-1 and MTs-2 references whows that their differences do not exceed 1.10/sup -13/ and the nonexcluded systematic frequency error of the MTs-3 is apparently close to 0.7.10/sup -13/.

  20. Atom chip based generation of entanglement for quantum metrology

    CERN Document Server

    Riedel, Max F; Li, Yun; Hänsch, Theodor W; Sinatra, Alice; Treutlein, Philipp

    2010-01-01

    Atom chips provide a versatile `quantum laboratory on a microchip' for experiments with ultracold atomic gases. They have been used in experiments on diverse topics such as low-dimensional quantum gases, cavity quantum electrodynamics, atom-surface interactions, and chip-based atomic clocks and interferometers. A severe limitation of atom chips, however, is that techniques to control atomic interactions and to generate entanglement have not been experimentally available so far. Such techniques enable chip-based studies of entangled many-body systems and are a key prerequisite for atom chip applications in quantum simulations, quantum information processing, and quantum metrology. Here we report experiments where we generate multi-particle entanglement on an atom chip by controlling elastic collisional interactions with a state-dependent potential. We employ this technique to generate spin-squeezed states of a two-component Bose-Einstein condensate and show that they are useful for quantum metrology. The obser...

  1. Metrology of human-based and other qualitative measurements

    Science.gov (United States)

    Pendrill, Leslie; Petersson, Niclas

    2016-09-01

    The metrology of human-based and other qualitative measurements is in its infancy—concepts such as traceability and uncertainty are as yet poorly developed. This paper reviews how a measurement system analysis approach, particularly invoking as performance metric the ability of a probe (such as a human being) acting as a measurement instrument to make a successful decision, can enable a more general metrological treatment of qualitative observations. Measures based on human observations are typically qualitative, not only in sectors, such as health care, services and safety, where the human factor is obvious, but also in customer perception of traditional products of all kinds. A principal challenge is that the usual tools of statistics normally employed for expressing measurement accuracy and uncertainty will probably not work reliably if relations between distances on different portions of scales are not fully known, as is typical of ordinal or other qualitative measurements. A key enabling insight is to connect the treatment of decision risks associated with measurement uncertainty to generalized linear modelling (GLM). Handling qualitative observations in this way unites information theory, the perceptive identification and choice paradigms of psychophysics. The Rasch invariant measure psychometric GLM approach in particular enables a proper treatment of ordinal data; a clear separation of probe and item attribute estimates; simple expressions for instrument sensitivity; etc. Examples include two aspects of the care of breast cancer patients, from diagnosis to rehabilitation. The Rasch approach leads in turn to opportunities of establishing metrological references for quality assurance of qualitative measurements. In psychometrics, one could imagine a certified reference for knowledge challenge, for example, a particular concept in understanding physics or for product quality of a certain health care service. Multivariate methods, such as Principal Component

  2. Diffraction-based overlay metrology for double patterning technologies

    Science.gov (United States)

    Dasari, Prasad; Korlahalli, Rahul; Li, Jie; Smith, Nigel; Kritsun, Oleg; Volkman, Cathy

    2009-03-01

    The extension of optical lithography to 32nm and beyond is made possible by Double Patterning Techniques (DPT) at critical levels of the process flow. The ease of DPT implementation is hindered by increased significance of critical dimension uniformity and overlay errors. Diffraction-based overlay (DBO) has shown to be an effective metrology solution for accurate determination of the overlay errors associated with double patterning [1, 2] processes. In this paper we will report its use in litho-freeze-litho-etch (LFLE) and spacer double patterning technology (SDPT), which are pitch splitting solutions that reduce the significance of overlay errors. Since the control of overlay between various mask/level combinations is critical for fabrication, precise and accurate assessment of errors by advanced metrology techniques such as spectroscopic diffraction based overlay (DBO) and traditional image-based overlay (IBO) using advanced target designs will be reported. A comparison between DBO, IBO and CD-SEM measurements will be reported. . A discussion of TMU requirements for 32nm technology and TMU performance data of LFLE and SDPT targets by different overlay approaches will be presented.

  3. Robust, frequency-stable and accurate mid-IR laser spectrometer based on frequency comb metrology of quantum cascade lasers up-converted in orientation-patterned GaAs

    CERN Document Server

    Hansen, Michael G; Vasilyev, Sergey V; Grisard, Arnaud; Lallier, Eric; Gérard, Bruno; Schiller, Stephan

    2013-01-01

    We demonstrate a robust and simple method for measurement, stabilization and tuning of the frequency of cw mid-infrared (MIR) lasers, in particular of quantum cascade lasers. The proof of principle is performed with a quantum cascade laser at 5.4 \\mu m, which is upconverted to 1.2 \\mu m by sum-frequency generation in orientation-patterned GaAs with the output of a standard high-power cw 1.5 \\mu m fiber laser. Both the 1.2 \\mu m and the 1.5 \\mu m waves are measured by a standard Er:fiber frequency comb. Frequency measurement at the 100 kHz-level, stabilization to sub-10 kHz level, controlled frequency tuning and long-term stability are demonstrated.

  4. Ice flood velocity calculating approach based on single view metrology

    Science.gov (United States)

    Wu, X.; Xu, L.

    2017-02-01

    Yellow River is the river in which the ice flood occurs most frequently in China, hence, the Ice flood forecasting has great significance for the river flood prevention work. In various ice flood forecast models, the flow velocity is one of the most important parameters. In spite of the great significance of the flow velocity, its acquisition heavily relies on manual observation or deriving from empirical formula. In recent years, with the high development of video surveillance technology and wireless transmission network, the Yellow River Conservancy Commission set up the ice situation monitoring system, in which live videos can be transmitted to the monitoring center through 3G mobile networks. In this paper, an approach to get the ice velocity based on single view metrology and motion tracking technique using monitoring videos as input data is proposed. First of all, River way can be approximated as a plane. On this condition, we analyze the geometry relevance between the object side and the image side. Besides, we present the principle to measure length in object side from image. Secondly, we use LK optical flow which support pyramid data to track the ice in motion. Combining the result of camera calibration and single view metrology, we propose a flow to calculate the real velocity of ice flood. At last we realize a prototype system by programming and use it to test the reliability and rationality of the whole solution.

  5. Digital holographic metrology based on multi-angle interferometry.

    Science.gov (United States)

    Dong, Jun; Jiang, Chao; Jia, Shuhai

    2016-09-15

    We propose a multi-angle interferometry method for digital holographic metrology. In an application of three-dimensional (3D) reconstruction, the hologram corresponding to a different illumination angle is recorded as the illumination angle with a single wavelength tilted at regular intervals by an electronically controlled rotating stage. A Fourier-transform-based axial depth scanning algorithm formed by the reconstructed phase is used to obtain the height point by point over the whole field of view. Hence, the 3D reconstruction can be obtained effectively; even the object has large depth discontinuities resulting from the difficulty of the phase unwrapping. Due to a monochrome source only being used, the method is available for objects with wavelength-dependent reflectivity and those that are free of chromatic aberration caused by the different wavelengths.

  6. Experimental Demonstration of Higher Precision Weak-Value-Based Metrology Using Power Recycling

    Science.gov (United States)

    Wang, Yi-Tao; Tang, Jian-Shun; Hu, Gang; Wang, Jian; Yu, Shang; Zhou, Zong-Quan; Cheng, Ze-Di; Xu, Jin-Shi; Fang, Sen-Zhi; Wu, Qing-Lin; Li, Chuan-Feng; Guo, Guang-Can

    2016-12-01

    The weak-value-based metrology is very promising and has attracted a lot of attention in recent years because of its remarkable ability in signal amplification. However, it is suggested that the upper limit of the precision of this metrology cannot exceed that of classical metrology because of the low sample size caused by the probe loss during postselection. Nevertheless, a recent proposal shows that this probe loss can be reduced by the power-recycling technique, and thus enhance the precision of weak-value-based metrology. Here we experimentally realize the power-recycled interferometric weak-value-based beam-deflection measurement and obtain the amplitude of the detected signal and white noise by discrete Fourier transform. Our results show that the detected signal can be strengthened by power recycling, and the power-recycled weak-value-based signal-to-noise ratio can surpass the upper limit of the classical scheme, corresponding to the shot-noise limit. This work sheds light on higher precision metrology and explores the real advantage of the weak-value-based metrology over classical metrology.

  7. Real cell overlay measurement through design based metrology

    Science.gov (United States)

    Yoo, Gyun; Kim, Jungchan; Park, Chanha; Lee, Taehyeong; Ji, Sunkeun; Jo, Gyoyeon; Yang, Hyunjo; Yim, Donggyu; Yamamoto, Masahiro; Maruyama, Kotaro; Park, Byungjun

    2014-04-01

    Until recent device nodes, lithography has been struggling to improve its resolution limit. Even though next generation lithography technology is now facing various difficulties, several innovative resolution enhancement technologies, based on 193nm wavelength, were introduced and implemented to keep the trend of device scaling. Scanner makers keep developing state-of-the-art exposure system which guarantees higher productivity and meets a more aggressive overlay specification. "The scaling reduction of the overlay error has been a simple matter of the capability of exposure tools. However, it is clear that the scanner contributions may no longer be the majority component in total overlay performance. The ability to control correctable overlay components is paramount to achieve the desired performance.(2)" In a manufacturing fab, the overlay error, determined by a conventional overlay measurement: by using an overlay mark based on IBO and DBO, often does not represent the physical placement error in the cell area of a memory device. The mismatch may arise from the size or pitch difference between the overlay mark and the cell pattern. Pattern distortion, caused by etching or CMP, also can be a source of the mismatch. Therefore, the requirement of a direct overlay measurement in the cell pattern gradually increases in the manufacturing field, and also in the development level. In order to overcome the mismatch between conventional overlay measurement and the real placement error of layer to layer in the cell area of a memory device, we suggest an alternative overlay measurement method utilizing by design, based metrology tool. A basic concept of this method is shown in figure1. A CD-SEM measurement of the overlay error between layer 1 and 2 could be the ideal method but it takes too long time to extract a lot of data from wafer level. An E-beam based DBM tool provides high speed to cover the whole wafer with high repeatability. It is enabled by using the design as a

  8. Using grating based X-ray contrast modalities for metrology

    DEFF Research Database (Denmark)

    Angel, Jais Andreas Breusch; Lauridsen, T.; Feidenhans'l, R.

    2014-01-01

    Traditionally, segmentation between multi-materials in CT is only available for cases, where material densities are not close to each other. A novel method called GBI offers a new possibility to overcome this problem, and was evaluated with respect to its metrological performance by comparisons...... to traceable measurements. The measurement results show that further development related to stability issues on the used CT is needed to create a metrological tool using GBI....

  9. Metrological analysis of a virtual flowmeter-based transducer for cryogenic helium

    Energy Technology Data Exchange (ETDEWEB)

    Arpaia, P., E-mail: pasquale.arpaia@unina.it [Department of Electrical Engineering and Information Technology, University of Napoli Federico II, Naples (Italy); Technology Department, European Organization for Nuclear Research (CERN), Geneva (Switzerland); Girone, M., E-mail: mario.girone@cern.ch [Technology Department, European Organization for Nuclear Research (CERN), Geneva (Switzerland); Department of Engineering, University of Sannio, Benevento (Italy); Liccardo, A., E-mail: annalisa.liccardo@unina.it [Department of Electrical Engineering and Information Technology, University of Napoli Federico II, Naples (Italy); Pezzetti, M., E-mail: marco.pezzetti@cern.ch [Technology Department, European Organization for Nuclear Research (CERN), Geneva (Switzerland); Piccinelli, F., E-mail: fabio.piccinelli@cern.ch [Department of Mechanical Engineering, University of Brescia, Brescia (Italy)

    2015-12-15

    The metrological performance of a virtual flowmeter-based transducer for monitoring helium under cryogenic conditions is assessed. At this aim, an uncertainty model of the transducer, mainly based on a valve model, exploiting finite-element approach, and a virtual flowmeter model, based on the Sereg-Schlumberger method, are presented. The models are validated experimentally on a case study for helium monitoring in cryogenic systems at the European Organization for Nuclear Research (CERN). The impact of uncertainty sources on the transducer metrological performance is assessed by a sensitivity analysis, based on statistical experiment design and analysis of variance. In this way, the uncertainty sources most influencing metrological performance of the transducer are singled out over the input range as a whole, at varying operating and setting conditions. This analysis turns out to be important for CERN cryogenics operation because the metrological design of the transducer is validated, and its components and working conditions with critical specifications for future improvements are identified.

  10. Metrological analysis of a virtual flowmeter-based transducer for cryogenic helium.

    Science.gov (United States)

    Arpaia, P; Girone, M; Liccardo, A; Pezzetti, M; Piccinelli, F

    2015-12-01

    The metrological performance of a virtual flowmeter-based transducer for monitoring helium under cryogenic conditions is assessed. At this aim, an uncertainty model of the transducer, mainly based on a valve model, exploiting finite-element approach, and a virtual flowmeter model, based on the Sereg-Schlumberger method, are presented. The models are validated experimentally on a case study for helium monitoring in cryogenic systems at the European Organization for Nuclear Research (CERN). The impact of uncertainty sources on the transducer metrological performance is assessed by a sensitivity analysis, based on statistical experiment design and analysis of variance. In this way, the uncertainty sources most influencing metrological performance of the transducer are singled out over the input range as a whole, at varying operating and setting conditions. This analysis turns out to be important for CERN cryogenics operation because the metrological design of the transducer is validated, and its components and working conditions with critical specifications for future improvements are identified.

  11. Image-based metrology of porous tissue engineering scaffolds

    Science.gov (United States)

    Rajagopalan, Srinivasan; Robb, Richard A.

    2006-03-01

    Tissue engineering is an interdisciplinary effort aimed at the repair and regeneration of biological tissues through the application and control of cells, porous scaffolds and growth factors. The regeneration of specific tissues guided by tissue analogous substrates is dependent on diverse scaffold architectural indices that can be derived quantitatively from the microCT and microMR images of the scaffolds. However, the randomness of pore-solid distributions in conventional stochastic scaffolds presents unique computational challenges. As a result, image-based characterization of scaffolds has been predominantly qualitative. In this paper, we discuss quantitative image-based techniques that can be used to compute the metrological indices of porous tissue engineering scaffolds. While bulk averaged quantities such as porosity and surface are derived directly from the optimal pore-solid delineations, the spatially distributed geometric indices are derived from the medial axis representations of the pore network. The computational framework proposed (to the best of our knowledge for the first time in tissue engineering) in this paper might have profound implications towards unraveling the symbiotic structure-function relationship of porous tissue engineering scaffolds.

  12. Enhacement of intrafield overlay using a design based metrology system

    Science.gov (United States)

    Jo, Gyoyeon; Ji, Sunkeun; Kim, Shinyoung; Kang, Hyunwoo; Park, Minwoo; Kim, Sangwoo; Kim, Jungchan; Park, Chanha; Yang, Hyunjo; Maruyama, Kotaro; Park, Byungjun

    2016-03-01

    As the scales of the semiconductor devices continue to shrink, accurate measurement and control of the overlay have been emphasized for securing more overlay margin. Conventional overlay analysis methods are based on the optical measurement of the overlay mark. However, the overlay data obtained from these optical methods cannot represent the exact misregistration between two layers at the circuit level. The overlay mismatch may arise from the size or pitch difference between the overlay mark and the real pattern. Pattern distortion, caused by CMP or etching, could be a source of the overlay mismatch as well. Another issue is the overlay variation in the real circuit pattern which varies depending on its location. The optical overlay measurement methods, such as IBO and DBO that use overlay mark on the scribeline, are not capable of defining the exact overlay values of the real circuit. Therefore, the overlay values of the real circuit need to be extracted to integrate the semiconductor device properly. The circuit level overlay measurement using CDSEM is time-consuming in extracting enough data to indicate overall trend of the chip. However DBM tool is able to derive sufficient data to display overlay tendency of the real circuit region with high repeatability. An E-beam based DBM(Design Based Metrology) tool can be an alternative overlay measurement method. In this paper, we are going to certify that the overlay values extracted from optical measurement cannot represent the circuit level overlay values. We will also demonstrate the possibility to correct misregistration between two layers using the overlay data obtained from the DBM system.

  13. Metrological management evaluation based on ISO10012: an empirical study in ISO-14001-certified Spanish companies

    Energy Technology Data Exchange (ETDEWEB)

    Beltran, Jaime; Rivas, Miguel [Andalusian Institute of Technology, C/Leonardo Da Vinci, 2, 41092 Sevilla (Spain); Munuzuri, Jesus [University of Seville, Av/Americo Vespucio, s/n. 41092 Sevilla (Spain); Gonzalez, Cristina [National University of Distance Education, C/Juan del Rosal, 2, 28040 Madrid (Spain)

    2010-01-15

    Environmental management systems based on the ISO 14001 standard rely strongly on metrological measurement and confirmation processes to certify the extent to which organizations monitor and improve their environmental behavior. Nevertheless, the literature lacks in studies that assess the influence of these metrological processes on the performance of environmental management in organizations, even now that the international standard ISO 10012 is already available to establish requisites and guidelines for the development of a metrological management system that is compatible with any other standardized management system. This work seeks to assess that influence through the development of an evaluation model for metrological management, which is then validated through an experimental analysis of the results obtained from the application of an audit process in 11 Spanish companies, all ISO-14001-certified and operating in different industrial sectors. (author)

  14. UV frequency metrology on CO (a3Pi); isotope effects and sensitivity to a variation of the proton-to-electron mass ratio

    CERN Document Server

    de Nijs, Adrian J; Eikema, Kjeld S E; Ubachs, Wim; Bethlem, Hendrick L

    2011-01-01

    UV frequency metrology has been performed on the a3Pi - X1Sigma+ (0,0) band of various isotopologues of CO using a frequency-quadrupled injection-seeded narrow-band pulsed Titanium:Sapphire laser referenced to a frequency comb laser. The band origin is determined with an accuracy of 5 MHz (delta \

  15. Improvement of the software Bernese for SLR data processing in the Main Metrological Centre of the State Time and Frequency Service

    Science.gov (United States)

    Tsyba, E.; Kaufman, M.

    2015-08-01

    Preparatory works for resuming operational calculations of the Earth rotation parameters based on the results of satellite laser ranging data processing (LAGEOS 1, LAGEOS 2) are to be completed in the Main Metrology Centre Of The State Time And Frequency Service (VNIIFTRI) in 2014. For this purpose BERNESE 5.2 software (Dach & Walser, 2014) was chosen as a base software which has been used for many years in the Main Metrological Centre of the State Time and Frequency Service to process phase observations of GLONASS and GPS satellites. Although in the BERNESE 5.2 software announced presentation the possibility of the SLR data processing is declared, it has not been fully implemented. In particular there is no such an essential element as corrective action (as input or resulting parameters) in the local time scale ("time bias"), etc. Therefore, additional program blocks have been developed and integrated into the BERNESE 5.2 software environment. The program blocks are written in Perl and Matlab program languages and can be used both for Windows and Linux, 32-bit and 64-bit platforms.

  16. Model-based optical metrology and visualization of 3-D complex objects

    Institute of Scientific and Technical Information of China (English)

    LIU Xiao-li; LI A-meng; ZHAO Xiao-bo; GAO Peng-dong; TIAN Jin-dong; PENG Xiang

    2007-01-01

    This letter addresses several key issues in the process of model-based optical metrology, including three dimensional (3D) sensing, calibration, registration and fusion of range images, geometric representation, and visualization of reconstructed 3D model by taking into account the shape measurement of 3D complex structures,and some experimental results are presented.

  17. Speckle-based at-wavelength metrology of X-ray mirrors with super accuracy.

    Science.gov (United States)

    Kashyap, Yogesh; Wang, Hongchang; Sawhney, Kawal

    2016-05-01

    X-ray active mirrors, such as bimorph and mechanically bendable mirrors, are increasingly being used on beamlines at modern synchrotron source facilities to generate either focused or "tophat" beams. As well as optical tests in the metrology lab, it is becoming increasingly important to optimise and characterise active optics under actual beamline operating conditions. Recently developed X-ray speckle-based at-wavelength metrology technique has shown great potential. The technique has been established and further developed at the Diamond Light Source and is increasingly being used to optimise active mirrors. Details of the X-ray speckle-based at-wavelength metrology technique and an example of its applicability in characterising and optimising a micro-focusing bimorph X-ray mirror are presented. Importantly, an unprecedented angular sensitivity in the range of two nanoradians for measuring the slope error of an optical surface has been demonstrated. Such a super precision metrology technique will be beneficial to the manufacturers of polished mirrors and also in optimization of beam shaping during experiments.

  18. Applications of on-product diffraction-based focus metrology in logic high volume manufacturing

    Science.gov (United States)

    Noyes, Ben F.; Mokaberi, Babak; Bolton, David; Li, Chen; Palande, Ashwin; Park, Kevin; Noot, Marc; Kea, Marc

    2016-03-01

    The integration of on-product diffraction-based focus (DBF) capability into the majority of immersion lithography layers in leading edge logic manufacturing has enabled new applications targeted towards improving cycle time and yield. A CD-based detection method is the process of record (POR) for excursion detection. The drawback of this method is increased cycle time and limited sampling due to CD-SEM metrology capacity constraints. The DBFbased method allows the addition of focus metrology samples to the existing overlay measurements on the integrated metrology (IM) system. The result enables the addition of measured focus to the SPC system, allowing a faster excursion detection method. For focus targeting, the current method involves using a dedicated focus-exposure matrix (FEM) on all scanners, resulting in lengthy analysis times and uncertainty in the best focus. The DBF method allows the measurement to occur on the IM system, on a regular production wafer, and at the same time as the exposure. This results in a cycle time gain as well as a less subjective determination of best focus. A third application aims to use the novel onproduct focus metrology data in order to apply per-exposure focus corrections to the scanner. These corrections are particularly effective at the edge of the wafer, where systematic layer-dependent effects can be removed using DBFbased scanner feedback. This paper will discuss the development of a methodology to accomplish each of these applications in a high-volume production environment. The new focus metrology method, sampling schemes, feedback mechanisms and analysis methods lead to improved focus control, as well as earlier detection of failures.

  19. Interaction-based nonlinear quantum metrology with a cold atomic ensemble

    OpenAIRE

    2014-01-01

    In this manuscript we present an experimental and theoretical investigation of quantum-noise-limited measurement by nonlinear interferometry, or from another perspective, quantum-noise-limited interaction-based measurement. The experimental work is performed using a polarization-based quantum interface between propagating light pulses and cold rubidium-87 atoms trapped in an optical dipole trap. We first review the theory of quantum metrology and estimation theory, and we describe theor...

  20. Design and simulation of GRIN objective lenses for an imaging fiber based speckle metrology system

    Science.gov (United States)

    Prabhathan, P.; Guru Prasad, A. S.; Haridas, Aswin; Chan, Kelvin H. K.; Murukeshan, V. M.

    2016-11-01

    Gradient-Index (GRIN) lenses are characterized by its small diameter and length, enabling them to be an effective lens for an integrated probe based imaging system. For a speckle-based surface metrology system, the imaging lens plays an important role in deciding the statistical dimensions of the speckles. In such cases, the design and simulation of the lens system would be a key process to better the performance of the lensed imaging fiber probe. In this context, this paper focuses on the design of lensed fiber probes for a speckle-based surface metrological imaging system that can find intra cavity interrogation applications. Different optical properties of GRIN lenses and imaging fibers are considered while designing the final probe distal end to meet the targeted specifications. Singlet GRIN lens configuration is analyzed for a front view configuration and a parameter optimization has been carried out to obtain the specifications including the field-of-view, resolution, working distance and magnification.

  1. Stable Similariton Generation in an All-Fiber Hybrid Mode-Locked Ring Laser for Frequency Metrology.

    Science.gov (United States)

    Lazarev, Vladimir; Krylov, Alexander; Dvoretskiy, Dmitriy; Sazonkin, Stanislav; Pnev, Alexey; Leonov, Stanislav; Shelestov, Dmitriy; Tarabrin, Mikhail; Karasik, Valeriy; Kireev, Alexey; Gubin, Mikhail

    2016-07-01

    Ultrashort pulse lasers constitute an important tool in the emerging field of optical frequency metrology and are enabling unprecedented measurement capabilities and new applications in a wide range of fields, including precision spectroscopy, atomic clocks, ultracold gases, and molecular fingerprinting. We demonstrate the generation of stable 127-fs self-similar pulses at a central wavelength of 1560 nm with 7.14-mW average output power. Similariton lasers have a low repetition rate deviation in the averaging time interval [Formula: see text], a low relative intensity noise [Formula: see text] (30 Hz to 10 kHz), a narrow single comb line width of 32 kHz, and high reliability. Thus, such lasers are highly promising for further development of the stabilized combs and open up a robust and substantially simplified route to synthesizing low-noise microwaves.

  2. Mathematical calibration procedure of a capacitive sensor-based indexed metrology platform

    Science.gov (United States)

    Brau-Avila, A.; Santolaria, J.; Acero, R.; Valenzuela-Galvan, M.; Herrera-Jimenez, V. M.; Aguilar, J. J.

    2017-03-01

    The demand for faster and more reliable measuring tasks for the control and quality assurance of modern production systems has created new challenges for the field of coordinate metrology. Thus, the search for new solutions in coordinate metrology systems and the need for the development of existing ones still persists. One example of such a system is the portable coordinate measuring machine (PCMM), the use of which in industry has considerably increased in recent years, mostly due to its flexibility for accomplishing in-line measuring tasks as well as its reduced cost and operational advantages compared to traditional coordinate measuring machines. Nevertheless, PCMMs have a significant drawback derived from the techniques applied in the verification and optimization procedures of their kinematic parameters. These techniques are based on the capture of data with the measuring instrument from a calibrated gauge object, fixed successively in various positions so that most of the instrument measuring volume is covered, which results in time-consuming, tedious and expensive verification and optimization procedures. In this work the mathematical calibration procedure of a capacitive sensor-based indexed metrology platform (IMP) is presented. This calibration procedure is based on the readings and geometric features of six capacitive sensors and their targets with nanometer resolution. The final goal of the IMP calibration procedure is to optimize the geometric features of the capacitive sensors and their targets in order to use the optimized data in the verification procedures of PCMMs.

  3. Virtual Distances Methodology as Verification Technique for AACMMs with a Capacitive Sensor Based Indexed Metrology Platform

    Directory of Open Access Journals (Sweden)

    Raquel Acero

    2016-11-01

    Full Text Available This paper presents a new verification procedure for articulated arm coordinate measuring machines (AACMMs together with a capacitive sensor-based indexed metrology platform (IMP based on the generation of virtual reference distances. The novelty of this procedure lays on the possibility of creating virtual points, virtual gauges and virtual distances through the indexed metrology platform’s mathematical model taking as a reference the measurements of a ball bar gauge located in a fixed position of the instrument’s working volume. The measurements are carried out with the AACMM assembled on the IMP from the six rotating positions of the platform. In this way, an unlimited number and types of reference distances could be created without the need of using a physical gauge, therefore optimizing the testing time, the number of gauge positions and the space needed in the calibration and verification procedures. Four evaluation methods are presented to assess the volumetric performance of the AACMM. The results obtained proved the suitability of the virtual distances methodology as an alternative procedure for verification of AACMMs using the indexed metrology platform.

  4. Virtual Distances Methodology as Verification Technique for AACMMs with a Capacitive Sensor Based Indexed Metrology Platform.

    Science.gov (United States)

    Acero, Raquel; Santolaria, Jorge; Brau, Agustin; Pueo, Marcos

    2016-11-18

    This paper presents a new verification procedure for articulated arm coordinate measuring machines (AACMMs) together with a capacitive sensor-based indexed metrology platform (IMP) based on the generation of virtual reference distances. The novelty of this procedure lays on the possibility of creating virtual points, virtual gauges and virtual distances through the indexed metrology platform's mathematical model taking as a reference the measurements of a ball bar gauge located in a fixed position of the instrument's working volume. The measurements are carried out with the AACMM assembled on the IMP from the six rotating positions of the platform. In this way, an unlimited number and types of reference distances could be created without the need of using a physical gauge, therefore optimizing the testing time, the number of gauge positions and the space needed in the calibration and verification procedures. Four evaluation methods are presented to assess the volumetric performance of the AACMM. The results obtained proved the suitability of the virtual distances methodology as an alternative procedure for verification of AACMMs using the indexed metrology platform.

  5. Temperature metrology

    Science.gov (United States)

    Fischer, J.; Fellmuth, B.

    2005-05-01

    The majority of the processes used by the manufacturing industry depend upon the accurate measurement and control of temperature. Thermal metrology is also a key factor affecting the efficiency and environmental impact of many high-energy industrial processes, the development of innovative products and the health and safety of the general population. Applications range from the processing, storage and shipment of perishable foodstuffs and biological materials to the development of more efficient and less environmentally polluting combustion processes for steel-making. Accurate measurement and control of temperature is, for instance, also important in areas such as the characterization of new materials used in the automotive, aerospace and semiconductor industries. This paper reviews the current status of temperature metrology. It starts with the determination of thermodynamic temperatures required on principle because temperature is an intensive quantity. Methods to determine thermodynamic temperatures are reviewed in detail to introduce the underlying physical basis. As these methods cannot usually be applied for practical measurements the need for a practical temperature scale for day-to-day work is motivated. The International Temperature Scale of 1990 and the Provisional Low Temperature Scale PLTS-2000 are described as important parts of the International System of Units to support science and technology. Its main importance becomes obvious in connection with industrial development and international markets. Every country is strongly interested in unique measures, in order to guarantee quality, reproducibility and functionability of products. The eventual realization of an international system, however, is only possible within the well-functioning organization of metrological laboratories. In developed countries the government established scientific institutes have certain metrological duties, as, for instance, the maintenance and dissemination of national

  6. Tomato classification based on laser metrology and computer algorithms

    Science.gov (United States)

    Igno Rosario, Otoniel; Muñoz Rodríguez, J. Apolinar; Martínez Hernández, Haydeé P.

    2011-08-01

    An automatic technique for tomato classification is presented based on size and color. The size is determined based on surface contouring by laser line scanning. Here, a Bezier network computes the tomato height based on the line position. The tomato color is determined by CIELCH color space and the components red and green. Thus, the tomato size is classified in large, medium and small. Also, the tomato is classified into six colors associated with its maturity. The performance and accuracy of the classification system is evaluated based on methods reported in the recent years. The technique is tested and experimental results are presented.

  7. Deep-ultraviolet frequency metrology with a narrowband titanium:sapphire laser

    NARCIS (Netherlands)

    Hannemann, S.

    2007-01-01

    Within the framework of this thesis resaerch project a narrow band titanium:sapphire laser was built. It provides nanosecond pulses that are subsequently upconverted to the deep ultraviolet frequency range. Absolute frequency calibration is achieved by linking the injection seeding light to a

  8. Industrial graphene metrology.

    Science.gov (United States)

    Kyle, Jennifer Reiber; Ozkan, Cengiz S; Ozkan, Mihrimah

    2012-07-07

    Graphene is an allotrope of carbon whose structure is based on one-atom-thick planar sheets of carbon atoms that are densely packed in a honeycomb crystal lattice. Its unique electrical and optical properties raised worldwide interest towards the design and fabrication of future electronic and optical devices with unmatched performance. At the moment, extensive efforts are underway to evaluate the reliability and performance of a number of such devices. With the recent advances in synthesizing large-area graphene sheets, engineers have begun investigating viable methodologies for conducting graphene metrology and quality control at industrial scales to understand a variety of reliability issues including defects, patternability, electrical, and physical properties. This review summarizes the current state of industrial graphene metrology and provides an overview of graphene metrology techniques. In addition, a recently developed large-area graphene metrology technique based on fluorescence quenching is introduced. For each metrology technique, the industrial metrics it measures are identified--layer thickness, edge structure, defects, Fermi level, and thermal conductivity--and a detailed description is provided as to how the measurements are performed. Additionally, the potential advantages of each technique for industrial use are identified, including throughput, scalability, sensitivity to substrate/environment, and on their demonstrated ability to achieve quantified results. The recently developed fluorescence-quenching metrology technique is shown to meet all the necessary criteria for industrial applications, rendering it the first industry-ready graphene metrology technique.

  9. Precision and accuracy testing of FMCW ladar-based length metrology.

    Science.gov (United States)

    Mateo, Ana Baselga; Barber, Zeb W

    2015-07-01

    The calibration and traceability of high-resolution frequency modulated continuous wave (FMCW) ladar sources is a requirement for their use in length and volume metrology. We report the calibration of FMCW ladar length measurement systems by use of spectroscopy of molecular frequency references HCN (C-band) or CO (L-band) to calibrate the chirp rate of the FMCW sources. Propagating the stated uncertainties from the molecular calibrations provided by NIST and measurement errors provide an estimated uncertainty of a few ppm for the FMCW system. As a test of this calibration, a displacement measurement interferometer with a laser wavelength close to that of our FMCW system was built to make comparisons of the relative precision and accuracy. The comparisons performed show <10  ppm agreement, which was within the combined estimated uncertainties of the FMCW system and interferometer.

  10. Semiconductor defect metrology using laser-based quantitative phase imaging

    Science.gov (United States)

    Zhou, Renjie; Edwards, Chris; Popescu, Gabriel; Goddard, Lynford

    2015-03-01

    A highly sensitive laser-based quantitative phase imaging tool, using an epi-illumination diffraction phase microscope, has been developed for silicon wafer defect inspection. The first system used a 532 nm solid-state laser and detected 20 nm by 100 nm by 110 nm defects in a 22 nm node patterned silicon wafer. The second system, using a 405 nm diode laser, is more sensitive and has enabled detection of 15 nm by 90 nm by 35 nm defects in a 9 nm node densely patterned silicon wafer. In addition to imaging, wafer scanning and image-post processing are also crucial for defect detection.

  11. Non-contact metrology of aspheric surfaces based on MWLI technology

    Science.gov (United States)

    Berger, G.; Petter, J.

    2013-09-01

    A non-contact optical scanning metrology solution measuring aspheric surfaces is presented, which is based on multi wavelength interferometry (MWLI). The technology yields high density 3D data in short measurement times (including set up time) and provides high, reproducible form measurement accuracy. It measures any asphere without restrictions in terms of spherical departures. In addition, measurement of a large variety of special optics is enabled, such as annular lenses, segmented optics, optics with diffractive steps, ground optics, optics made of opaque and transparent materials, and small and thin optics (e.g. smart phone lenses). The measurement instrument can be used under production conditions.

  12. Dimensional Metrology for Microtechnology

    DEFF Research Database (Denmark)

    Bariani, Paolo

    2005-01-01

    This ph. D. project was aimed at developing and validating techniques for dimensional metrology of: miniaturized items, microsystem components, and surfaces. In particular the study was focused on techniques based on: AFM-CMM integration and Scanning Electron Microscopy (SEM). Development...... was proposed and the principle demonstrated on software gauges. Simulations of Surface Mapping were done, based on the model developed. Direct performance verification of the Large Range AFM was eventually carried out, and lateral metrology was possible, in the millimeter range, with accuracy in the order...... at high magnifications was, proposed and this has resulted into a patent application. The final part of the thesis is devoted to applications of dimensional metrology to case studies. Three applications are presented, two of them are investigations of surface metrology, while the third is about extraction...

  13. Frequency metrology of helium around 1083 nm and determination of the nuclear charge radius

    CERN Document Server

    Pastor, P Cancio; Giusfredi, G; De Natale, P; Inguscio, M; Yerokhin, V A; Pachucki, K

    2012-01-01

    We measure the absolute frequency of seven out of the nine allowed transitions between the 2^3S and 2^3P hyperfine manifolds in a metastable ^3He beam by using an optical frequency comb synthesizer-assisted spectrometer. The relative uncertainty of our measurements ranges from 1x10^{-11} to 5x10^{-12}, which is, to our knowledge,the most precise result for any optical ^3He transition to date. The resulting 2^3P-2^3S centroid frequency is 276702827203.1 (2.3) kHz. Comparing this value with the known result for the ^4He centroid and performing {\\em ab initio} QED calculations of the ^4He-^3He isotope shift, we extract the difference of the squared nuclear charge radii \\delta r^2 of ^3He and ^4He. Our result for \\delta r^2=1.075 (3) fm^2 disagrees by about 4 sigma with the recent determination [R. van Rooij {\\em et al.}, Science {\\bf 333}, 196 (2011)].

  14. Metrologically speaking

    Science.gov (United States)

    Hansen, Matthew E.

    2008-08-01

    Optical metrology is a science and an art. Education in the engineering disciplines concentrates on technical knowledge transfer. However, creativity and imagination are required in partnership with these technical skills to generate truly innovative results. This presentation investigates strategies and methodologies of working in which the exploration of potential solutions to optical metrology problems becomes more of a creative process than the strict application of technical know-how.

  15. Validation of virtual instrument for data analysis in metrology of time and frequency; Validacao do instrumento virtual para analise de dados em metrologia de tempo e frequencia

    Energy Technology Data Exchange (ETDEWEB)

    Jordao, Bruno; Quaresma, Daniel; Rocha, Pedro; Carvalho, Ricardo, E-mail: bjordan@on.br [Observatorio Nacional (ON), Rio de Janeiro, RJ (Brazil). Laboratorio Primario de Tempo e Frequencia; Peixoto, Jose Guilherme [Instituto de Radioprotecao e Dosimetria (LNMRI/IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Laboratorio Nacional de Metrologia das Radiacoes Ionizantes

    2016-07-01

    Commercial Software (CS) for collection, analysis and plot time and frequency data plots are being increasingly used in reference laboratories worldwide. With this, it has greatly improved the results of calculations of uncertainty for these values. We propose the creation of a collection of software and data analysis using Virtual Instruments (VI) developed the Primary Laboratory Time and frequency of the National Observatory - ON and validation of this instrument. To validate the instrument developed, it made a comparative analysis between the results obtained (VI) with the results obtained by (CS) widely used in many metrology laboratories. From these results we can conclude that there was equivalence between the analyzed data. (author)

  16. Automatic Three-Dimensional Measurement of Large-Scale Structure Based on Vision Metrology

    Directory of Open Access Journals (Sweden)

    Zhaokun Zhu

    2014-01-01

    Full Text Available All relevant key techniques involved in photogrammetric vision metrology for fully automatic 3D measurement of large-scale structure are studied. A new kind of coded target consisting of circular retroreflective discs is designed, and corresponding detection and recognition algorithms based on blob detection and clustering are presented. Then a three-stage strategy starting with view clustering is proposed to achieve automatic network orientation. As for matching of noncoded targets, the concept of matching path is proposed, and matches for each noncoded target are found by determination of the optimal matching path, based on a novel voting strategy, among all possible ones. Experiments on a fixed keel of airship have been conducted to verify the effectiveness and measuring accuracy of the proposed methods.

  17. Flexible resources for quantum metrology

    Science.gov (United States)

    Friis, Nicolai; Orsucci, Davide; Skotiniotis, Michalis; Sekatski, Pavel; Dunjko, Vedran; Briegel, Hans J.; Dür, Wolfgang

    2017-06-01

    Quantum metrology offers a quadratic advantage over classical approaches to parameter estimation problems by utilising entanglement and nonclassicality. However, the hurdle of actually implementing the necessary quantum probe states and measurements, which vary drastically for different metrological scenarios, is usually not taken into account. We show that for a wide range of tasks in metrology, 2D cluster states (a particular family of states useful for measurement-based quantum computation) can serve as flexible resources that allow one to efficiently prepare any required state for sensing, and perform appropriate (entangled) measurements using only single qubit operations. Crucially, the overhead in the number of qubits is less than quadratic, thus preserving the quantum scaling advantage. This is ensured by using a compression to a logarithmically sized space that contains all relevant information for sensing. We specifically demonstrate how our method can be used to obtain optimal scaling for phase and frequency estimation in local estimation problems, as well as for the Bayesian equivalents with Gaussian priors of varying widths. Furthermore, we show that in the paradigmatic case of local phase estimation 1D cluster states are sufficient for optimal state preparation and measurement.

  18. A Cryogenic Radiometry Based Spectral Responsivity Scale at the National Metrology Centre

    Science.gov (United States)

    Xu, Gan; Huang, Xuebo

    This paper describes the spectral responsivity scale established at the National Metrology Centre (NMC) based on cryogenic radiometry. A primary standard - a mechanically pumped cryogenic radiometer together with a set of intensity-stabilised lasers provides traceability for optical power measurement with an uncertainty in the order of 10-4 at 14 discrete wavelengths in the spectral range from 350 nm to 800 nm. A silicon trap detector, with its absolute responsivity calibrated against the cryogenic radiometer is used as a transfer standard for the calibration of other detectors using a specially built spectral comparator. The relative spectral responsivity of a detector at other wavelengths can be determined through the use of a cavity pyroelectric detector and the extrapolation technique. With this scale, NMC is capable to calibrate the spectral responsivity of different type of photo detectors from 250 nm to 1640 nm with an uncertainty range from 3.7% to 0.3%.

  19. Precision metrology.

    Science.gov (United States)

    Jiang, X; Whitehouse, D J

    2012-08-28

    This article is a summary of the Satellite Meeting, which followed on from the Discussion Meeting at the Royal Society on 'Ultra-precision engineering: from physics to manufacture', held at the Kavli Royal Society International Centre, Chicheley Hall, Buckinghamshire, UK. The meeting was restricted to 18 invited experts in various aspects of precision metrology from academics from the UK and Sweden, Government Institutes from the UK and Germany and global aerospace industries. It examined and identified metrology problem areas that are, or may be, limiting future developments in precision engineering and, in particular, metrology. The Satellite Meeting was intended to produce a vision that will inspire academia and industry to address the solutions of those open-ended problems identified. The discussion covered three areas, namely the function of engineering parts, their measurement and their manufacture, as well as their interactions.

  20. Towards a Uniform Metrological Assessment of Grating-Based Optical Fiber Sensors: From Refractometers to Biosensors.

    Science.gov (United States)

    Chiavaioli, Francesco; Gouveia, Carlos A J; Jorge, Pedro A S; Baldini, Francesco

    2017-06-21

    A metrological assessment of grating-based optical fiber sensors is proposed with the aim of providing an objective evaluation of the performance of this sensor category. Attention was focused on the most common parameters, used to describe the performance of both optical refractometers and biosensors, which encompassed sensitivity, with a distinction between volume or bulk sensitivity and surface sensitivity, resolution, response time, limit of detection, specificity (or selectivity), reusability (or regenerability) and some other parameters of generic interest, such as measurement uncertainty, accuracy, precision, stability, drift, repeatability and reproducibility. Clearly, the concepts discussed here can also be applied to any resonance-based sensor, thus providing the basis for an easier and direct performance comparison of a great number of sensors published in the literature up to now. In addition, common mistakes present in the literature made for the evaluation of sensor performance are highlighted, and lastly a uniform performance assessment is discussed and provided. Finally, some design strategies will be proposed to develop a grating-based optical fiber sensing scheme with improved performance.

  1. Design-based metrology: beyond CD/EPE metrics to evaluate printability performance

    Science.gov (United States)

    Halder, Sandip; Mailfert, Julien; Leray, Philippe; Rio, David; Peng, Yi-Hsing; Laenens, Bart

    2016-03-01

    Process-window (PW) evaluation is critical to assess the lithography process quality and limitations. Usual CD-based PW gives only a partial answer. Simulations such as Tachyon LMC (Lithography Manufacturability Check) can efficiently overcome this limitation by analyzing the entire predicted resist contours. But so far experimental measurements did not allow such flexibility. This paper shows an innovative experimental flow, which allows the user to directly validate LMC results across PW for a select group of reference patterns, thereby overcoming the limitations found in the traditional CD-based PW analysis. To evaluate the process window on wafer more accurately, we take advantage of design based metrology and extract experimental contours from the CD-SEM measurements. Then we implement an area metric to quantify the area coverage of the experimental contours with respect to the intended ones, using a defined "sectorization" for the logic structures. This `sectorization' aims to differentiate specific areas on the logic structures being analyzed, such as corners, line-ends, short and long lines. This way, a complete evaluation of the information contained in each CD-SEM picture is performed, without having to discard any information. This solution doesn't look at the area coverage of an entire feature, but uses a `sectorization' to differentiate specific feature areas such as corners, line-ends, short and long lines, and thus look at those area coverages. An assessment of resist model/OPC quality/process quality at sub nm-level accuracy is rendered possible.

  2. A novel design-based global CDU metrology for 1X nm node logic devices

    Science.gov (United States)

    Yoon, Young-Keun; Chung, Dong H.; Kim, Min-Ho; Seo, Jung-Uk; Kim, Byung-Gook; Jeon, Chan-Uk; Hur, JiUk; Cho, Wonil; Yamamoto, Tetsuya

    2013-09-01

    As dimension of device shrinks to 1X nm node, an extreme control of critical dimension uniformity (CDU) of masks becomes one of key techniques for mask and wafer fabrication. For memory devices, a large number of optical techniques have been studied and applied to mask production so far. The advantages of these methods are to eliminate the sampling dependency due to their high throughput, to minimize the local CD errors due to their large field of view (FOV) and to improve the correlation with wafer infield uniformity if they have scanner-like optics. For logic devices, however, CD-SEM has been a single solution to characterize CD performance of logic masks for a long time and simple monitoring patterns, instead of the cell patterns, have been measured to monitor the CD quality of masks. Therefore a global CDU of the mask tends to show its ambiguity because of the limited number of measurement sites and large local CD errors. An application of optical metrology for logic mask is a challenging task because patterns are more complex and random in shape and because there is no guarantee of finding patterns for CDU everywhere on the mask. CDU map still consists of the results from the indirect measurements and the traditional definition of uniformity, a statistical deviation of a typical pattern, seems to be unsuitable for logic CDU. A new definition of CDU is required in order to maximize the coverage area on a mask. In this study, we have focused of the possibility of measuring cell patterns and of using an inspection tool with data base handling capability, KLA Teron617, to find the areas and positions where the repeating patterns exist and the patterns which satisfy a certain set of condition and we have devised a new definition of CDU, which can handle multiple target CDs. Then we have checked the feasibility and validity of our new methodology through evaluation its fundamental performance such as accuracy, repeatability, and correlation with other CD metrology

  3. 4D metrology of flapping-wing micro air vehicle based on fringe projection

    Science.gov (United States)

    Zhang, Qican; Huang, Lei; Chin, Yao-Wei; Keong, Lau-Gih; Asundi, Anand

    2013-06-01

    Inspired by dominant flight of the natural flyers and driven by civilian and military purposes, micro air vehicle (MAV) has been developed so far by passive wing control but still pales in aerodynamic performance. Better understanding of flapping wing flight mechanism is eager to improve MAV's flight performance. In this paper, a simple and effective 4D metrology technique to measure full-field deformation of flapping membrane wing is presented. Based on fringe projection and 3D Fourier analysis, the fast and complex dynamic deformation, including wing rotation and wing stroke, of a flapping wing during its flight can be accurately reconstructed from the deformed fringe patterns recorded by a highspeed camera. An experiment was carried on a flapping-wing MAV with 5-cm span membrane wing beating at 30 Hz, and the results show that this method is effective and will be useful to the aerodynamicist or micro aircraft designer for visualizing high-speed complex wing deformation and consequently aid the design of flapping wing mechanism to enhanced aerodynamic performance.

  4. Improving focus performance at litho using diffraction-based focus metrology, novel calibration methods, interface, and control loop

    Science.gov (United States)

    Hu, Jiarui; Chen, Y. L.; Chen, K. H.; Lee, Brian; Tsai, Frankie; Ke, C. M.; Liao, C. H.; Ngo, Desmond; Gosali, Benny; Tijssen, Robin; Huang, Vincent; Tu, Ward; Noot, Marc; Escalante Marun, Maryana; Leewis, Christian; Luijten, Carlo; Staals, Frank; Van Veen, Martijn; Furthner, Francois; Young, Stuart; Bhattacharyya, Kaustuve

    2016-03-01

    In advanced optical lithography the requirements of focus control continues to tighten. Usable depth of focus (DoF) is already quite low due to typical sources of focus errors, such as topography, wafer warpage and the thickness of photoresist. And now the usable DoF is further decreased by hotspots (design and imaging hotspots). All these have put extra challenges to improve focus metrology, scanner focus stability calibrations and on-product correction mechanisms. Asymmetric focus targets are developed to address robustness in focus measurements using diffraction-based focus (DBF and μDBF) metrology. A new layout specific calibration methodology is introduced for baseline focus setup and control in order to improve scanner focus uniformity and stability using the measurements of the above mentioned asymmetric targets. A similar metrology is also used for on product focus measurements. Moreover, a few novel alternative methods are also investigated for on-product focus measurements. Data shows good correlation between DBF and process on record (POR) method using traditional FEM. The new focus calibration demonstrated robustness, stability and speed. This technical publication will report the data from all the above activities including results from various product layers.

  5. Fundamental units: physics and metrology

    CERN Document Server

    Okun, Lev Borisovich

    2003-01-01

    The problem of fundamental units is discussed in the context of achievements of both theoretical physics and modern metrology. On one hand, due to fascinating accuracy of atomic clocks, the traditional macroscopic standards of metrology (second, metre, kilogram) are giving way to standards based on fundamental units of nature: velocity of light $c$ and quantum of action $h$. On the other hand, the poor precision of gravitational constant $G$, which is widely believed to define the ``cube of theories'' and the units of the future ``theory of everything'', does not allow to use $G$ as a fundamental dimensional constant in metrology. The electromagnetic units in SI are actually based on concepts of prerelativistic classical electrodynamics such as ether, electric permitivity and magnetic permeability of vacuum. Concluding remarks are devoted to terminological confusion which accompanies the progress in basic physics and metrology.

  6. Laser Metrology in the Micro-Arcsecond Metrology Testbed

    Science.gov (United States)

    An, Xin; Marx, D.; Goullioud, Renaud; Zhao, Feng

    2004-01-01

    The Space Interferometer Mission (SIM), scheduled for launch in 2009, is a space-born visible light stellar interferometer capable of micro-arcsecond-level astrometry. The Micro-Arcsecond Metrology testbed (MAM) is the ground-based testbed that incorporates all the functionalities of SIM minus the telescope, for mission-enabling technology development and verification. MAM employs a laser heterodyne metrology system using the Sub-Aperture Vertex-to-Vertex (SAVV) concept. In this paper, we describe the development and modification of the SAVV metrology launchers and the metrology instrument electronics, precision alignments and pointing control, locating cyclic error sources in the MAM testbed and methods to mitigate the cyclic errors, as well as the performance under the MAM performance metrics.

  7. Development of a speckle-based portable device for in situ metrology of synchrotron X-ray mirrors

    Science.gov (United States)

    Kashyap, Yogesh; Wang, Hongchang; Sawhney, Kawal

    2016-01-01

    A portable device for in situ metrology of synchrotron X-ray mirrors based on the near-field speckle scanning technique has been developed. Ultra-high angular sensitivity is achieved by scanning a piece of abrasive paper or filter membrane in the X-ray beam. In addition to the compact setup and ease of implementation, a user-friendly graphical user interface has been developed to ensure that optimizing active X-ray mirrors is simple and fast. The functionality and feasibility of this device have been demonstrated by characterizing and optimizing X-ray mirrors. PMID:27577767

  8. Development of a speckle-based portable device for in situ metrology of synchrotron X-ray mirrors.

    Science.gov (United States)

    Kashyap, Yogesh; Wang, Hongchang; Sawhney, Kawal

    2016-09-01

    A portable device for in situ metrology of synchrotron X-ray mirrors based on the near-field speckle scanning technique has been developed. Ultra-high angular sensitivity is achieved by scanning a piece of abrasive paper or filter membrane in the X-ray beam. In addition to the compact setup and ease of implementation, a user-friendly graphical user interface has been developed to ensure that optimizing active X-ray mirrors is simple and fast. The functionality and feasibility of this device have been demonstrated by characterizing and optimizing X-ray mirrors.

  9. FOREWORD: Materials metrology Materials metrology

    Science.gov (United States)

    Bennett, Seton; Valdés, Joaquin

    2010-04-01

    It seems that so much of modern life is defined by the materials we use. From aircraft to architecture, from cars to communications, from microelectronics to medicine, the development of new materials and the innovative application of existing ones have underpinned the technological advances that have transformed the way we live, work and play. Recognizing the need for a sound technical basis for drafting codes of practice and specifications for advanced materials, the governments of countries of the Economic Summit (G7) and the European Commission signed a Memorandum of Understanding in 1982 to establish the Versailles Project on Advanced Materials and Standards (VAMAS). This project supports international trade by enabling scientific collaboration as a precursor to the drafting of standards. The VAMAS participants recognized the importance of agreeing a reliable, universally accepted basis for the traceability of the measurements on which standards depend for their preparation and implementation. Seeing the need to involve the wider metrology community, VAMAS approached the Comité International des Poids et Mesures (CIPM). Following discussions with NMI Directors and a workshop at the BIPM in February 2005, the CIPM decided to establish an ad hoc Working Group on the metrology applicable to the measurement of material properties. The Working Group presented its conclusions to the CIPM in October 2007 and published its final report in 2008, leading to the signature of a Memorandum of Understanding between VAMAS and the BIPM. This MoU recognizes the work that is already going on in VAMAS as well as in the Consultative Committees of the CIPM and establishes a framework for an ongoing dialogue on issues of materials metrology. The question of what is meant by traceability in the metrology of the properties of materials is particularly vexed when the measurement results depend on a specified procedure. In these cases, confidence in results requires not only traceable

  10. Electron counting capacitance standard and quantum metrology triangle experiments at PTB

    Science.gov (United States)

    Scherer, H.; Schurr, J.; Ahlers, F. J.

    2017-06-01

    This paper summarizes the final results of the electron counting capacitance standard experiment at the Physikalisch-Technische Bundesanstalt (PTB) achieved since the publication of a preliminary result in 2012. All systematic uncertainty contributions were experimentally quantified and are discussed. Frequency-dependent measurements on the 1 pF cryogenic capacitor were performed using a high-precision transformer-based capacitance bridge with a relative uncertainty of 0.03 µF F-1. The results revealed a crucial problem related to the capacitor, which hampered realizing the quantum metrology triangle with an accuracy corresponding to a combined total uncertainty of better than a few parts per million and eventually caused the discontinuation of the experiment at PTB. This paper provides a conclusion on the implications for future quantum metrology triangle experiments from the latest CODATA adjustment of fundamental constants, and summarizes perspectives and outlooks on future quantum metrology triangle experiments based on topical developments in small-current metrology.

  11. Interaction-based quantum metrology showing scaling beyond the Heisenberg limit.

    Science.gov (United States)

    Napolitano, M; Koschorreck, M; Dubost, B; Behbood, N; Sewell, R J; Mitchell, M W

    2011-03-24

    Quantum metrology aims to use entanglement and other quantum resources to improve precision measurement. An interferometer using N independent particles to measure a parameter χ can achieve at best the standard quantum limit of sensitivity, δχ ∝ N(-1/2). However, using N entangled particles and exotic states, such an interferometer can in principle achieve the Heisenberg limit, δχ ∝ N(-1). Recent theoretical work has argued that interactions among particles may be a valuable resource for quantum metrology, allowing scaling beyond the Heisenberg limit. Specifically, a k-particle interaction will produce sensitivity δχ ∝ N(-k) with appropriate entangled states and δχ ∝ N(-(k-1/2)) even without entanglement. Here we demonstrate 'super-Heisenberg' scaling of δχ ∝ N(-3/2) in a nonlinear, non-destructive measurement of the magnetization of an atomic ensemble. We use fast optical nonlinearities to generate a pairwise photon-photon interaction (corresponding to k = 2) while preserving quantum-noise-limited performance. We observe super-Heisenberg scaling over two orders of magnitude in N, limited at large numbers by higher-order nonlinear effects, in good agreement with theory. For a measurement of limited duration, super-Heisenberg scaling allows the nonlinear measurement to overtake in sensitivity a comparable linear measurement with the same number of photons. In other situations, however, higher-order nonlinearities prevent this crossover from occurring, reflecting the subtle relationship between scaling and sensitivity in nonlinear systems. Our work shows that interparticle interactions can improve sensitivity in a quantum-limited measurement, and experimentally demonstrates a new resource for quantum metrology.

  12. A Toolbox of Metrology-Based Techniques for Optical System Alignment

    Science.gov (United States)

    Coulter, Phillip; Ohl, Raymond G.; Blake, Peter N.; Bos, Brent J.; Eichhorn, William L.; Gum, Jeffrey S.; Hadjimichael, Theodore J.; Hagopian, John G.; Hayden, Joseph E.; Hetherington, Samuel E.; Kubalak, David A.; McLean, Kyle F.; McMann, Joseph; Redman, Kevin W.; Sampler, Henry P.; Wenzel, Greg W.; Young, Jerrod L.

    2016-01-01

    The NASA Goddard Space Flight Center (GSFC) and its partners have broad experience in the alignment of flight optical instruments and spacecraft structures. Over decades, GSFC developed alignment capabilities and techniques for a variety of optical and aerospace applications. In this paper, we provide an overview of a subset of the capabilities and techniques used on several recent projects in a "toolbox" format. We discuss a range of applications, from small-scale optical alignment of sensors to mirror and bench examples that make use of various large-volume metrology techniques. We also discuss instruments and analytical tools.

  13. A toolbox of metrology-based techniques for optical system alignment

    Science.gov (United States)

    Coulter, Phillip; Ohl, Raymond G.; Blake, Peter N.; Bos, Brent J.; Chambers, Victor J.; Eichhorn, William L.; Gum, Jeffrey S.; Hadjimichael, Theodore J.; Hagopian, John G.; Hayden, Joseph E.; Hetherington, Samuel E.; Kubalak, David A.; Mclean, Kyle F.; McMann, Joseph C.; Redman, Kevin W.; Sampler, Henry P.; Wenzel, Greg W.; Young, Jerrod L.

    2016-10-01

    The NASA Goddard Space Flight Center (GSFC) and its partners have broad experience in the alignment of flight optical instruments and spacecraft structures. Over decades, GSFC developed alignment capabilities and techniques for a variety of optical and aerospace applications. In this paper, we provide an overview of a subset of the capabilities and techniques used on several recent projects in a "toolbox" format. We discuss a range of applications, from small-scale optical alignment of sensors to mirror and bench examples that make use of various large-volume metrology techniques. We also discuss instruments and analytical tools.

  14. Performance-based gear metrology kinematic, transmission, error computation and diagnosis

    CERN Document Server

    Mark, William D

    2012-01-01

    A mathematically rigorous explanation of how manufacturing deviations and damage on the working surfaces of gear teeth cause transmission-error contributions to vibration excitations Some gear-tooth working-surface manufacturing deviations of significant amplitude cause negligible vibration excitation and noise, yet others of minuscule amplitude are a source of significant vibration excitation and noise.   Presently available computer-numerically-controlled dedicated gear metrology equipment can measure such error patterns on a gear in a few hours in sufficient detail to enable

  15. A low power 10 V programmable array based on Nb x Si1-x Josephson junctions for metrology applications

    Science.gov (United States)

    Knipper, Richard; Anders, Solveig; Schubert, Marco; Peiselt, Katja; Scheller, Thomas; Franke, Dirk; Dellith, Jan; Meyer, Hans-Georg

    2016-09-01

    Josephson junctions generate, when subjected to microwave irradiation, voltages with a very high precision and are used in metrology applications. So-called PJVS (programmable Josephson voltage-standards) are capable of generating both AC and DC voltages of up to 10 V. Our work addresses a full fabrication scenario for 10 V PJVS arrays driven at 70 GHz to be used in low microwave-power conditions as in, but not limited to GUNN diodes or cryocooler applications. Nb x Si1-x in its function as a barrier material was characterised with AFM, RBS and reflectometry in order to establish a reliable technological foundation. A 10 V PJVS array driven with microwave power below 50 mW is further presented, which was achieved by optimising the fabrication technology regarding the degree of homogeneity of the Josephson junctions composition and thickness. Control over these parameters is crucial in choosing a stable and well-suited characteristic voltage (I c R n product) and critical current density j c. With this, a low-power operation of a PJVS array is possible without the need for liquid helium cooling, which is currently limiting the availability of PJVS based metrology.

  16. Scatterometry-based metrology for SAQP pitch walking using virtual reference

    Science.gov (United States)

    Kagalwala, Taher; Vaid, Alok; Mahendrakar, Sridhar; Lenahan, Michael; Fang, Fang; Isbester, Paul; Shifrin, Michael; Etzioni, Yoav; Cepler, Aron; Yellai, Naren; Dasari, Prasad; Bozdog, Cornel

    2016-03-01

    Advanced technology nodes, 10nm and beyond, employing multi-patterning techniques for pitch reduction pose new process and metrology challenges in maintaining consistent positioning of structural features. Self-Aligned Quadruple Patterning (SAQP) process is used to create the Fins in FinFET devices with pitch values well below optical lithography limits. The SAQP process bares compounding effects from successive Reactive Ion Etch (RIE) and spacer depositions. These processes induce a shift in the pitch value from one fin compared to another neighboring fin. This is known as pitch walking. Pitch walking affects device performance as well as later processes which work on an assumption that there is consistent spacing between fins. In SAQP there are 3 pitch walking parameters of interest, each linked to specific process steps in the flow. These pitch walking parameters are difficult to discriminate at a specific process step by singular evaluation technique or even with reference metrology such as Transmission Electron Microscopy (TEM). In this paper we will utilize a virtual reference to generate a scatterometry model to measure pitch walk for SAQP process flow.

  17. Metrology of vibration measurements by laser techniques

    Science.gov (United States)

    von Martens, Hans-Jürgen

    2008-06-01

    Metrology as the art of careful measurement has been understood as uniform methodology for measurements in natural sciences, covering methods for the consistent assessment of experimental data and a corpus of rules regulating application in technology and in trade and industry. The knowledge, methods and tools available for precision measurements can be exploited for measurements at any level of uncertainty in any field of science and technology. A metrological approach to the preparation, execution and evaluation (including expression of uncertainty) of measurements of translational and rotational motion quantities using laser interferometer methods and techniques will be presented. The realization and dissemination of the SI units of motion quantities (vibration and shock) have been based on laser interferometer methods specified in international documentary standards. New and upgraded ISO standards are reviewed with respect to their suitability for ensuring traceable vibration measurements and calibrations in an extended frequency range of 0.4 Hz to higher than 100 kHz. Using adequate vibration exciters to generate sufficient displacement or velocity amplitudes, the upper frequency limits of the laser interferometer methods specified in ISO 16063-11 for frequencies procedures (i.e. measurement uncertainty 0.05 % at frequencies <= 10 kHz, <= 1 % up to 100 kHz).

  18. 64nm pitch metal1 double patterning metrology: CD and OVL control by SEMCD, image based overlay and diffraction based overlay

    Science.gov (United States)

    Ducoté, Julien; Dettoni, Florent; Bouyssou, Régis; Le-Gratiet, Bertrand; Carau, Damien; Dezauzier, Christophe

    2015-03-01

    Patterning process control of advanced nodes has required major changes over the last few years. Process control needs of critical patterning levels since 28nm technology node is extremely aggressive showing that metrology accuracy/sensitivity must be finely tuned. The introduction of pitch splitting (Litho-Etch-Litho-Etch) at 14FDSOInm node requires the development of specific metrologies to adopt advanced process control (for CD, overlay and focus corrections). The pitch splitting process leads to final line CD uniformities that are a combination of the CD uniformities of the two exposures, while the space CD uniformities are depending on both CD and OVL variability. In this paper, investigations of CD and OVL process control of 64nm minimum pitch at Metal1 level of 14FDSOI technology, within the double patterning process flow (Litho, hard mask etch, line etch) are presented. Various measurements with SEMCD tools (Hitachi), and overlay tools (KT for Image Based Overlay - IBO, and ASML for Diffraction Based Overlay - DBO) are compared. Metrology targets are embedded within a block instanced several times within the field to perform intra-field process variations characterizations. Specific SEMCD targets were designed for independent measurement of both line CD (A and B) and space CD (A to B and B to A) for each exposure within a single measurement during the DP flow. Based on those measurements correlation between overlay determined with SEMCD and with standard overlay tools can be evaluated. Such correlation at different steps through the DP flow is investigated regarding the metrology type. Process correction models are evaluated with respect to the measurement type and the intra-field sampling.

  19. A graphene based frequency quadrupler

    Science.gov (United States)

    Cheng, Chuantong; Huang, Beiju; Mao, Xurui; Zhang, Zanyun; Zhang, Zan; Geng, Zhaoxin; Xue, Ping; Chen, Hongda

    2017-04-01

    Benefit from exceptional electrical transport properties, graphene receives worldwide attentions, especially in the domain of high frequency electronics. Due to absence of effective bandgap causing off-state the device, graphene material is extraordinarily suitable for analog circuits rather than digital applications. With this unique ambipolar behavior, graphene can be exploited and utilized to achieve high performance for frequency multipliers. Here, dual-gated graphene field-effect transistors have been firstly used to achieve frequency quadrupling. Two Dirac points in the transfer curves of the designed GFETs can be observed by tuning top-gate voltages, which is essential to generate the fourth harmonic. By applying 200 kHz sinusoid input, arround 50% of the output signal radio frequency power is concentrated at the desired frequency of 800 kHz. Additionally, in suitable operation areas, our devices can work as high performance frequency doublers and frequency triplers. Considered both simple device structure and potential superhigh carrier mobility of graphene material, graphene-based frequency quadruplers may have lots of superiorities in regards to ultrahigh frequency electronic applications in near future. Moreover, versatility of carbon material system is far-reaching for realization of complementary metal-oxide-semiconductor compatible electrically active devices.

  20. Ocular microtremor laser speckle metrology

    Science.gov (United States)

    Al-Kalbani, M.; Mihaylova, E.; Collins, N.; Toal, V.; Coakley, D.; Boyle, G.

    2009-02-01

    Ocular Microtremor (OMT) is a continual, high frequency physiological tremor of the eye present in all subjects even when the eye is apparently at rest. OMT causes a peak to peak displacement of around 150nm-2500nm with a broadband frequency spectrum between 30Hz to 120Hz; with a peak at about 83Hz. OMT carries useful clinical information on depth of consciousness and on some neurological disorders. Nearly all quantitative clinical investigations have been based on OMT measurements using an eye contacting piezoelectric probe which has low clinical acceptability. Laser speckle metrology is a candidate for a high resolution, non-contacting, compact, portable OMT measurement technique. However, tear flow and biospeckle might be expected to interfere with the displacement information carried by the speckle. The paper investigates the properties of the scattered speckle of laser light (λ = 632.8nm) from the eye sclera to assess the feasibility of using speckle techniques to measure OMT such as the speckle correlation. The investigation is carried using a high speed CMOS video camera adequate to capture the high frequency of the tremor. The investigation is supported by studies using an eye movement simulator (a bovine sclera driven by piezoelectric bimorphs). The speckle contrast and the frame to frame spatiotemporal variations are analyzed to determine if the OMT characteristics are detectable within speckle changes induced by the biospeckle or other movements.

  1. Wide-range length metrology by dual-imaging-unit atomic force microscope based on porous alumina.

    Science.gov (United States)

    Zhang, Dongxian; Zhang, Haijun; Lin, Xiaofeng

    2004-06-15

    A new dual-imaging-unit atomic force microscope (DIU-AFM) was developed for wide-range length metrology. In the DIU-AFM, two AFM units were combined, one as a reference unit, and the other a test one. Their probes with Z piezo elements and tips were horizontally set in parallel at the same height to reduce errors due to geometric asymmetry. An XY scanner was attached to an XY block that was able to move in the X direction with a step of about 500 nm. A standard porous alumina film was employed as the reference sample. Both reference sample and test sample were installed at the center of the XY scanner on the same surface and were simultaneously imaged. The two images had the same lateral size, and thus the length of the test sample image could be accurately measured by counting the number of periodic features of the reference one. The XY block together with the XY scanner were next moved in the X direction for about 1.5 microm and a second pair of reference and test images were obtained by activating the scanner. In this way, a series of pairs of images were acquired and could be spliced into two wide-range reference and test images, respectively. Again, the two spliced images were of the same size and the length of test image was measured based on the reference one. This article presents a discussion about the structure and control of the DIU-AFM system. Some experiments were carried out on the system to demonstrate the method of length calculation and measurement. Experiments show a satisfactory result of wide-range length metrology based on the hexagonal features of the porous alumina with a periodic length of several tens of nanometers. Using this method the DIU-AFM is capable of realizing nanometer-order accuracy length metrology when covering a wide range from micron to several hundreds of microns, or even up to millimeter order.

  2. Wafer-based aberration metrology for lithographic systems using overlay measurements on targets imaged from phase-shift gratings.

    Science.gov (United States)

    van Haver, Sven; Coene, Wim M J; D'havé, Koen; Geypen, Niels; van Adrichem, Paul; de Winter, Laurens; Janssen, Augustus J E M; Cheng, Shaunee

    2014-04-20

    In this paper, a new methodology is presented to derive the aberration state of a lithographic projection system from wafer metrology data. For this purpose, new types of phase-shift gratings (PSGs) are introduced, with special features that give rise to a simple linear relation between the PSG image displacement and the phase aberration function of the imaging system. By using the PSGs as the top grating in a diffraction-based overlay stack, their displacement can be measured as an overlay error using a standard wafer metrology tool. In this way, the overlay error can be used as a measurand based on which the phase aberration function in the exit pupil of the lithographic system can be reconstructed. In practice, the overlay error is measured for a set of different PSG targets, after which this information serves as input to a least-squares optimization problem that, upon solving, provides estimates for the Zernike coefficients describing the aberration state of the lithographic system. In addition to a detailed method description, this paper also deals with the additional complications that arise when the method is implemented experimentally and this leads to a number of model refinements and a required calibration step. Finally, the overall performance of the method is assessed through a number of experiments in which the aberration state of the lithographic system is intentionally detuned and subsequently estimated by the new method. These experiments show a remarkably good agreement, with an error smaller than 5  mλ, among the requested aberrations, the aberrations measured by the on-tool aberration sensor, and the results of the new wafer-based method.

  3. Simultaneous acquisition of 3D shape and deformation by combination of interferometric and correlation-based laser speckle metrology.

    Science.gov (United States)

    Dekiff, Markus; Berssenbrügge, Philipp; Kemper, Björn; Denz, Cornelia; Dirksen, Dieter

    2015-12-01

    A metrology system combining three laser speckle measurement techniques for simultaneous determination of 3D shape and micro- and macroscopic deformations is presented. While microscopic deformations are determined by a combination of Digital Holographic Interferometry (DHI) and Digital Speckle Photography (DSP), macroscopic 3D shape, position and deformation are retrieved by photogrammetry based on digital image correlation of a projected laser speckle pattern. The photogrammetrically obtained data extend the measurement range of the DHI-DSP system and also increase the accuracy of the calculation of the sensitivity vector. Furthermore, a precise assignment of microscopic displacements to the object's macroscopic shape for enhanced visualization is achieved. The approach allows for fast measurements with a simple setup. Key parameters of the system are optimized, and its precision and measurement range are demonstrated. As application examples, the deformation of a mandible model and the shrinkage of dental impression material are measured.

  4. A simulation-based study on the influence of beam hardening in X-ray computed tomography for dimensional metrology.

    Science.gov (United States)

    Lifton, Joseph J; Malcolm, Andrew A; McBride, John W

    2015-01-01

    X-ray computed tomography (CT) is a radiographic scanning technique for visualising cross-sectional images of an object non-destructively. From these cross-sectional images it is possible to evaluate internal dimensional features of a workpiece which may otherwise be inaccessible to tactile and optical instruments. Beam hardening is a physical process that degrades the quality of CT images and has previously been suggested to influence dimensional measurements. Using a validated simulation tool, the influence of spectrum pre-filtration and beam hardening correction are evaluated for internal and external dimensional measurements. Beam hardening is shown to influence internal and external dimensions in opposition, and to have a greater influence on outer dimensions compared to inner dimensions. The results suggest the combination of spectrum pre-filtration and a local gradient-based surface determination method are able to greatly reduce the influence of beam hardening in X-ray CT for dimensional metrology.

  5. Oscillator metrology with software defined radio

    CERN Document Server

    Sherman, Jeff A

    2016-01-01

    Analog electrical elements such as mixers, filters, transfer oscillators, isolating buffers, dividers, and even transmission lines contribute technical noise and unwanted environmental coupling in time and frequency measurements. Software defined radio (SDR) techniques replace many of these analog components with digital signal processing (DSP) on rapidly sampled signals. We demonstrate that, generically, commercially available multi-channel SDRs are capable of time and frequency metrology, outperforming purpose-built devices by as much as an order-of-magnitude. For example, for signals at 10 MHz and 6 GHz, we observe SDR time deviation noise floors of about 20 fs and 1 fs, respectively, in under 10 ms of averaging. Examining the other complex signal component, we find a relative amplitude measurement instability of 3e-7 at 5 MHz. We discuss the scalability of a SDR-based system for simultaneous measurement of many clocks. SDR's frequency agility allows for comparison of oscillators at widely different freque...

  6. Multi-petahertz electronic metrology.

    Science.gov (United States)

    Garg, M; Zhan, M; Luu, T T; Lakhotia, H; Klostermann, T; Guggenmos, A; Goulielmakis, E

    2016-10-20

    The frequency of electric currents associated with charge carriers moving in the electronic bands of solids determines the speed limit of electronics and thereby that of information and signal processing. The use of light fields to drive electrons promises access to vastly higher frequencies than conventionally used, as electric currents can be induced and manipulated on timescales faster than that of the quantum dephasing of charge carriers in solids. This forms the basis of terahertz (10(12) hertz) electronics in artificial superlattices, and has enabled light-based switches and sampling of currents extending in frequency up to a few hundred terahertz. Here we demonstrate the extension of electronic metrology to the multi-petahertz (10(15) hertz) frequency range. We use single-cycle intense optical fields (about one volt per ångström) to drive electron motion in the bulk of silicon dioxide, and then probe its dynamics by using attosecond (10(-18) seconds) streaking to map the time structure of emerging isolated attosecond extreme ultraviolet transients and their optical driver. The data establish a firm link between the emission of the extreme ultraviolet radiation and the light-induced intraband, phase-coherent electric currents that extend in frequency up to about eight petahertz, and enable access to the dynamic nonlinear conductivity of silicon dioxide. Direct probing, confinement and control of the waveform of intraband currents inside solids on attosecond timescales establish a method of realizing multi-petahertz coherent electronics. We expect this technique to enable new ways of exploring the interplay between electron dynamics and the structure of condensed matter on the atomic scale.

  7. Technique for Calibration of Chassis components based on encoding marks and machine Vision metrology

    Institute of Scientific and Technical Information of China (English)

    SONG Li-mei; ZHANG Chun-bo; WEI Yi-ying; CHEN Hua-wei

    2011-01-01

    @@ A novel technique for calibrating crucial parameters of chassis components is proposed, which utilizes the machine vision metrology to measure 3D coordinates of the center of a component's hole for assembling in the 3D world coordinate system.In the measurement, encoding marks with special patterns will be assembled on the chassis component associated with cross drone and staff gauge located near the chassis.The geometry and coordinates of the cross drone consist of two planes orthogonal to each other and the staff gauge is in 3D space with high precision.A few images are taken by a highresolution camera in different orientations and perspectives.The 3D coordinates of 5 key points on the encoding marks will be calculated by the machine vision technique and those of the center of the holes to be calibrated will be calculated by the deduced algorithm in this paper.Experimental results show that the algorithm and the technique can satisfy the precision requirement when the components are assembled, and the average measurement precision provided by the algorithm is 0.0174 mm.

  8. Capability Handbook- offline metrology

    DEFF Research Database (Denmark)

    Islam, Aminul; Marhöfer, David Maximilian; Tosello, Guido

    This offline metrological capability handbook has been made in relation to HiMicro Task 3.3. The purpose of this document is to assess the metrological capability of the HiMicro partners and to gather the information of all available metrological instruments in the one single document. It provides...... a quick overview of what is possible today by the state of the art, what the HiMicro consortium can do and what metrological requirements we have concerning the HiMicro industrial demonstrators....

  9. Droplet-based, high-brightness extreme ultraviolet laser plasma source for metrology

    Science.gov (United States)

    Vinokhodov, A. Yu.; Krivokorytov, M. S.; Sidelnikov, Yu. V.; Krivtsun, V. M.; Medvedev, V. V.; Koshelev, K. N.

    2016-10-01

    We report on the development of a high brightness source of extreme ultraviolet radiation (EUV) with a working wavelength of 13.5 nm. The source is based on a laser-produced plasma driven by pulsed radiation of a Nd:YAG laser system. Liquid droplets of Sn-In eutectic alloy were used as the source fuel. The droplets were created by a droplet generator operating in the jet break-up regime. The EUV emission properties of the plasma, including the emission spectrum, time profile, and conversion efficiency of laser radiation into useful 13.5 nm photons, have been characterized. Using the shadowgraphy technique, we demonstrated the production of corpuscular debris by the plasma source and the influence of the plasma on the neighboring droplet targets. The high-frequency laser operation was simulated by usage of the dual pulse regime. Based on the experimental results, we discuss the physical phenomena that could affect the source operation at high repetition rates. Finally, we estimate that an average source brightness of 1.2 kW/mm2 sr is feasible at a high repetition rate.

  10. Metrology of ground-based satellite validation: co-location mismatch and smoothing issues of total ozone comparisons

    Directory of Open Access Journals (Sweden)

    T. Verhoelst

    2015-12-01

    Full Text Available Comparisons with ground-based correlative measurements constitute a key component in the validation of satellite data on atmospheric composition. The error budget of these comparisons contains not only the measurement errors but also several terms related to differences in sampling and smoothing of the inhomogeneous and variable atmospheric field. A versatile system for Observing System Simulation Experiments (OSSEs, named OSSSMOSE, is used here to quantify these terms. Based on the application of pragmatic observation operators onto high-resolution atmospheric fields, it allows a simulation of each individual measurement, and consequently, also of the differences to be expected from spatial and temporal field variations between both measurements making up a comparison pair. As a topical case study, the system is used to evaluate the error budget of total ozone column (TOC comparisons between GOME-type direct fitting (GODFITv3 satellite retrievals from GOME/ERS2, SCIAMACHY/Envisat, and GOME-2/MetOp-A, and ground-based direct-sun and zenith–sky reference measurements such as those from Dobsons, Brewers, and zenith-scattered light (ZSL-DOAS instruments, respectively. In particular, the focus is placed on the GODFITv3 reprocessed GOME-2A data record vs. the ground-based instruments contributing to the Network for the Detection of Atmospheric Composition Change (NDACC. The simulations are found to reproduce the actual measurements almost to within the measurement uncertainties, confirming that the OSSE approach and its technical implementation are appropriate. This work reveals that many features of the comparison spread and median difference can be understood as due to metrological differences, even when using strict co-location criteria. In particular, sampling difference errors exceed measurement uncertainties regularly at most mid- and high-latitude stations, with values up to 10 % and more in extreme cases. Smoothing difference errors only

  11. Metrology of ground-based satellite validation: co-location mismatch and smoothing issues of total ozone comparisons

    Science.gov (United States)

    Verhoelst, T.; Granville, J.; Hendrick, F.; Köhler, U.; Lerot, C.; Pommereau, J.-P.; Redondas, A.; Van Roozendael, M.; Lambert, J.-C.

    2015-12-01

    Comparisons with ground-based correlative measurements constitute a key component in the validation of satellite data on atmospheric composition. The error budget of these comparisons contains not only the measurement errors but also several terms related to differences in sampling and smoothing of the inhomogeneous and variable atmospheric field. A versatile system for Observing System Simulation Experiments (OSSEs), named OSSSMOSE, is used here to quantify these terms. Based on the application of pragmatic observation operators onto high-resolution atmospheric fields, it allows a simulation of each individual measurement, and consequently, also of the differences to be expected from spatial and temporal field variations between both measurements making up a comparison pair. As a topical case study, the system is used to evaluate the error budget of total ozone column (TOC) comparisons between GOME-type direct fitting (GODFITv3) satellite retrievals from GOME/ERS2, SCIAMACHY/Envisat, and GOME-2/MetOp-A, and ground-based direct-sun and zenith-sky reference measurements such as those from Dobsons, Brewers, and zenith-scattered light (ZSL-)DOAS instruments, respectively. In particular, the focus is placed on the GODFITv3 reprocessed GOME-2A data record vs. the ground-based instruments contributing to the Network for the Detection of Atmospheric Composition Change (NDACC). The simulations are found to reproduce the actual measurements almost to within the measurement uncertainties, confirming that the OSSE approach and its technical implementation are appropriate. This work reveals that many features of the comparison spread and median difference can be understood as due to metrological differences, even when using strict co-location criteria. In particular, sampling difference errors exceed measurement uncertainties regularly at most mid- and high-latitude stations, with values up to 10 % and more in extreme cases. Smoothing difference errors only play a role in the

  12. Metrology of ground-based satellite validation: co-location mismatch and smoothing issues of total ozone comparisons

    Directory of Open Access Journals (Sweden)

    T. Verhoelst

    2015-08-01

    Full Text Available Comparisons with ground-based correlative measurements constitute a key component in the validation of satellite data on atmospheric composition. The error budget of these comparisons contains not only the measurement uncertainties but also several terms related to differences in sampling and smoothing of the inhomogeneous and variable atmospheric field. A versatile system for Observing System Simulation Experiments (OSSEs, named OSSSMOSE, is used here to quantify these terms. Based on the application of pragmatic observation operators onto high-resolution atmospheric fields, it allows a simulation of each individual measurement, and consequently also of the differences to be expected from spatial and temporal field variations between both measurements making up a comparison pair. As a topical case study, the system is used to evaluate the error budget of total ozone column (TOC comparisons between on the one hand GOME-type direct fitting (GODFITv3 satellite retrievals from GOME/ERS2, SCIAMACHY/Envisat, and GOME-2/MetOp-A, and on the other hand direct-sun and zenith-sky reference measurements such as from Dobsons, Brewers, and zenith scattered light (ZSL-DOAS instruments respectively. In particular, the focus is placed on the GODFITv3 reprocessed GOME-2A data record vs. the ground-based instruments contributing to the Network for the Detection of Atmospheric Composition Change (NDACC. The simulations are found to reproduce the actual measurements almost to within the measurement uncertainties, confirming that the OSSE approach and its technical implementation are appropriate. This work reveals that many features of the comparison spread and median difference can be understood as due to metrological differences, even when using strict co-location criteria. In particular, sampling difference errors exceed measurement uncertainties regularly at most mid- and high-latitude stations, with values up to 10 % and more in extreme cases. Smoothing

  13. Resolving critical dimension drift over time in plasma etching through virtual metrology based wafer-to-wafer control

    Science.gov (United States)

    Lee, Ho Ki; Baek, Kye Hyun; Shin, Kyoungsub

    2017-06-01

    As semiconductor devices are scaled down to sub-20 nm, process window of plasma etching gets extremely small so that process drift or shift becomes more significant. This study addresses one of typical process drift issues caused by consumable parts erosion over time and provides feasible solution by using virtual metrology (VM) based wafer-to-wafer control. Since erosion of a shower head has center-to-edge area dependency, critical dimensions (CDs) at the wafer center and edge area get reversed over time. That CD trend is successfully estimated on a wafer-to-wafer basis by a partial least square (PLS) model which combines variables from optical emission spectroscopy (OES), VI-probe and equipment state gauges. R 2 of the PLS model reaches 0.89 and its prediction performance is confirmed in a mass production line. As a result, the model can be exploited as a VM for wafer-to-wafer control. With the VM, advanced process control (APC) strategy is implemented to solve the CD drift. Three σ of CD across wafer is improved from the range (1.3-2.9 nm) to the range (0.79-1.7 nm). Hopefully, results introduced in this paper will contribute to accelerating implementation of VM based APC strategy in semiconductor industry.

  14. The quality of measurements a metrological reference

    CERN Document Server

    Fridman, A E

    2012-01-01

    This book provides a detailed discussion and commentary on the fundamentals of metrology. The fundamentals of metrology, the principles underlying the design of the SI International System of units, the theory of measurement error, a new methodology for estimation of measurement accuracy based on uncertainty, and methods for reduction of measured results and estimation of measurement uncertainty are all discussed from a modern point of view. The concept of uncertainty is shown to be consistent with the classical theory of accuracy. The theory of random measurement errors is supplemented by a very general description based on the generalized normal distribution; systematic instrumental error is described in terms of a methodology for normalizing the metrological characteristics of measuring instruments. A new international system for assuring uniformity of measurements based on agreements between national metrological institutes is discussed, in addition to the role and procedure for performance of key compari...

  15. Metrology and Energy Conservation

    Institute of Scientific and Technical Information of China (English)

    Xuan Xiang

    2006-01-01

    @@ May 20 is World Metrology Day and the theme of this year is "Metrology and Energy Conservation." Energy is not only a vital issue for China, but also for the world. In order to implement Proposal of the CPC Central Committee on the 11th Five-Year Program for National Economic and Social Development, the government bulletin of 5th Plenary Session of the 16th CPC Central Committee announced that "there shall be marked improvement on resource utilization; the energy consumption for unit GDP shall cut 20%, water consumption of unit industrial added value drop 30%... and the recycle ratio of industrial solid wastes shall raise by 60%." These are key targets of economic development during the 11th five-year program. To make full use of metrology for energy conservation and energy utilization, the competent metrology department of Chinese Goyernment advanced metrology program in light of China's energy status.

  16. Heterodyne Interferometer Angle Metrology

    Science.gov (United States)

    Hahn, Inseob; Weilert, Mark A.; Wang, Xu; Goullioud, Renaud

    2010-01-01

    A compact, high-resolution angle measurement instrument has been developed that is based on a heterodyne interferometer. The common-path heterodyne interferometer metrology is used to measure displacements of a reflective target surface. In the interferometer setup, an optical mask is used to sample the measurement laser beam reflecting back from a target surface. Angular rotations, around two orthogonal axes in a plane perpendicular to the measurement- beam propagation direction, are determined simultaneously from the relative displacement measurement of the target surface. The device is used in a tracking telescope system where pitch and yaw measurements of a flat mirror were simultaneously performed with a sensitivity of 0.1 nrad, per second, and a measuring range of 0.15 mrad at a working distance of an order of a meter. The nonlinearity of the device is also measured less than one percent over the measurement range.

  17. Mirrors for X-ray telescopes: Fresnel diffraction-based computation of Point Spread Functions from metrology

    CERN Document Server

    Raimondi, Lorenzo

    2014-01-01

    The imaging sharpness of an X-ray telescope is chiefly determined by the optical quality of its focusing optics, which in turn mostly depends on the shape accuracy and the surface finishing of the grazing incidence X-ray mirrors that compose the optical modules. In order to ensure the imaging performance during the mirror manufacturing, a fundamental step is represented by the prediction of the mirror Point Spread Function (PSF) from the metrology of its surface. Traditionally, the PSF computation in X-rays is assumed to be different depending on whether the surface defects are classified as figure errors or roughness [...] The aim of this work is to overcome this limit, providing analytical formulae, valid at any light wavelength, to compute the PSF of an X-ray mirror shell from the measured longitudinal profiles and the roughness Power Spectral Density (PSD), without distinguishing spectral ranges with different treatments. The method we adopted is based on the Huygens-Fresnel principle to compute the diffr...

  18. Theoretical analysis and system design of two-photon based optical frequency standards

    Science.gov (United States)

    Burger, J. P.; Jivan, P.; Matthee, C.; Kritzinger, R.; Hussein, H.; Terra, O.

    2014-06-01

    The National Metrology Institute of South Africa (NMISA) is developing a new optical frequency standard based on the Rubidium two-photon transition in collaboration with the National Institute of Standards (NIS, Egypt) that will use both bulk and fiber optics in the system. This is system is called A-POD; an acronym for a portable photonic oscillator device. Rubidium two-photon standards can yield relatively simple and precise standards that are compatible with standard Ti:Sapphire optical frequency combs, as well as the need for a precise frequency standard in the optical telecommunication domain and for measurement of length with a visible beam. The robustness and transportability of the standard are important considerations for the optical frequency standard. This projects implements a framework for better two-photon standards that can be highly accurate, and possibly compete with much more complex clocks in the metrology environment, and especially so in the smaller national metrology institutes found in the developing world. This paper discusses the design constraints and the development considerations towards the optical setup. The robustness and transportability was greatly improved via the usage of optical fiber in the light source of the system, or even in atom-light interaction region. Of particular importance are the beam parameters inside the atomic interaction area. The extent of Doppler broadening and the intensity dependent line shift have to be optimized within practical extents, where both these aspects are affected by the beam shape and optical geometry. A way to fully treat the optical beam effects together with atomic movement is proposed. Furthermore a method is proposed to do real time compensation of intensity dependent light shift, which could have major applicability to frequency standards in general - the complexity is shifted from physical setups to digital signal processing, which is easily adaptable and stable.

  19. The elusive Heisenberg limit in quantum-enhanced metrology

    Science.gov (United States)

    Demkowicz-Dobrzański, Rafał; Kołodyński, Jan; Guţă, Mădălin

    2012-01-01

    Quantum precision enhancement is of fundamental importance for the development of advanced metrological optical experiments, such as gravitational wave detection and frequency calibration with atomic clocks. Precision in these experiments is strongly limited by the 1/√N shot noise factor with N being the number of probes (photons, atoms) employed in the experiment. Quantum theory provides tools to overcome the bound by using entangled probes. In an idealized scenario this gives rise to the Heisenberg scaling of precision 1/N. Here we show that when decoherence is taken into account, the maximal possible quantum enhancement in the asymptotic limit of infinite N amounts generically to a constant factor rather than quadratic improvement. We provide efficient and intuitive tools for deriving the bounds based on the geometry of quantum channels and semi-definite programming. We apply these tools to derive bounds for models of decoherence relevant for metrological applications including: depolarization, dephasing, spontaneous emission and photon loss. PMID:22990859

  20. Lithography, metrology and nanomanufacturing.

    Science.gov (United States)

    Liddle, J Alexander; Gallatin, Gregg M

    2011-07-01

    Semiconductor chip manufacturing is by far the predominant nanomanufacturing technology in the world today. Top-down lithography techniques are used for fabrication of logic and memory chips since, in order to function, these chips must essentially be perfect. Assuring perfection requires expensive metrology. Top of the line logic sells for several hundred thousand dollars per square metre and, even though the required metrology is expensive, it is a small percentage of the overall manufacturing cost. The level of stability and control afforded by current lithography tools means that much of this metrology can be online and statistical. In contrast, many of the novel types of nanomanufacturing currently being developed will produce products worth only a few dollars per square metre. To be cost effective, the required metrology must cost proportionately less. Fortunately many of these nanofabrication techniques, such as block copolymer self-assembly, colloidal self-assembly, DNA origami, roll-2-roll nano-imprint, etc., will not require the same level of perfection to meet specification. Given the variability of these self-assembly processes, in order to maintain process control, these techniques will require some level of real time online metrology. Hence we are led to the conclusion that future nanomanufacturing may well necessitate "cheap" nanometre scale metrology which functions real time and on-line, e.g. at GHz rates, in the production stream. In this paper we review top-down and bottom-up nanofabrication techniques and compare and contrast the various metrology requirements.

  1. Oscillator metrology with software defined radio.

    Science.gov (United States)

    Sherman, Jeff A; Jördens, Robert

    2016-05-01

    Analog electrical elements such as mixers, filters, transfer oscillators, isolating buffers, dividers, and even transmission lines contribute technical noise and unwanted environmental coupling in time and frequency measurements. Software defined radio (SDR) techniques replace many of these analog components with digital signal processing (DSP) on rapidly sampled signals. We demonstrate that, generically, commercially available multi-channel SDRs are capable of time and frequency metrology, outperforming purpose-built devices by as much as an order-of-magnitude. For example, for signals at 10 MHz and 6 GHz, we observe SDR time deviation noise floors of about 20 fs and 1 fs, respectively, in under 10 ms of averaging. Examining the other complex signal component, we find a relative amplitude measurement instability of 3 × 10(-7) at 5 MHz. We discuss the scalability of a SDR-based system for simultaneous measurement of many clocks. SDR's frequency agility allows for comparison of oscillators at widely different frequencies. We demonstrate a novel and extreme example with optical clock frequencies differing by many terahertz: using a femtosecond-laser frequency comb and SDR, we show femtosecond-level time comparisons of ultra-stable lasers with zero measurement dead-time.

  2. Relative Navigation for Satellite Formation Flying based on Radio Frequency Metrology

    NARCIS (Netherlands)

    Sun, R.

    2014-01-01

    To increase mission return, utilizing two or more spacecraft instead of one may sometimes be superior. This is especially true when a large spaceborne instrument needs to be created through larger and configurable baselines, such as telescopes and interferometers. However, coordinating the alignment

  3. Precision Metrology Using Weak Measurements

    Science.gov (United States)

    Zhang, Lijian; Datta, Animesh; Walmsley, Ian A.

    2015-05-01

    Weak values and measurements have been proposed as a means to achieve dramatic enhancements in metrology based on the greatly increased range of possible measurement outcomes. Unfortunately, the very large values of measurement outcomes occur with highly suppressed probabilities. This raises three vital questions in weak-measurement-based metrology. Namely, (Q1) Does postselection enhance the measurement precision? (Q2) Does weak measurement offer better precision than strong measurement? (Q3) Is it possible to beat the standard quantum limit or to achieve the Heisenberg limit with weak measurement using only classical resources? We analyze these questions for two prototypical, and generic, measurement protocols and show that while the answers to the first two questions are negative for both protocols, the answer to the last is affirmative for measurements with phase-space interactions, and negative for configuration space interactions. Our results, particularly the ability of weak measurements to perform at par with strong measurements in some cases, are instructive for the design of weak-measurement-based protocols for quantum metrology.

  4. Precision metrology using weak measurements.

    Science.gov (United States)

    Zhang, Lijian; Datta, Animesh; Walmsley, Ian A

    2015-05-29

    Weak values and measurements have been proposed as a means to achieve dramatic enhancements in metrology based on the greatly increased range of possible measurement outcomes. Unfortunately, the very large values of measurement outcomes occur with highly suppressed probabilities. This raises three vital questions in weak-measurement-based metrology. Namely, (Q1) Does postselection enhance the measurement precision? (Q2) Does weak measurement offer better precision than strong measurement? (Q3) Is it possible to beat the standard quantum limit or to achieve the Heisenberg limit with weak measurement using only classical resources? We analyze these questions for two prototypical, and generic, measurement protocols and show that while the answers to the first two questions are negative for both protocols, the answer to the last is affirmative for measurements with phase-space interactions, and negative for configuration space interactions. Our results, particularly the ability of weak measurements to perform at par with strong measurements in some cases, are instructive for the design of weak-measurement-based protocols for quantum metrology.

  5. 7th International Workshop on Advanced Optical Imaging and Metrology

    CERN Document Server

    2014-01-01

    In continuation of the FRINGE Workshop Series this Proceeding contains all contributions presented at the 7. International Workshop on Advanced Optical Imaging and Metrology. The FRINGE Workshop Series is dedicated to the presentation, discussion and dissemination of recent results in Optical Imaging and Metrology. Topics of particular interest for the 7. Workshop are: - New methods and tools for the generation, acquisition, processing, and evaluation of data in Optical Imaging and Metrology (digital wavefront engineering, computational imaging, model-based reconstruction, compressed sensing, inverse problems solution) - Application-driven technologies in Optical Imaging and Metrology (high-resolution, adaptive, active, robust, reliable, flexible, in-line, real-time) - High-dynamic range solutions in Optical Imaging and Metrology (from macro to nano) - Hybrid technologies in Optical Imaging and Metrology (hybrid optics, sensor and data fusion, model-based solutions, multimodality) - New optical sensors, imagi...

  6. Metrology Measurement Capabilities

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, L.M.

    2003-11-12

    This document contains descriptions of Federal Manufacturing & Technologies (FM&T) Metrology capabilities, traceability flow charts, and the measurement uncertainty of each measurement capability. Metrology provides NIST traceable precision measurements or equipment calibration for a wide variety of parameters, ranges, and state-of-the-art uncertainties. Metrology laboratories conform to the requirements of the Department of Energy Development and Production Manual Chapter 8.4, ANSI/ISO/IEC ANSI/ISO/IEC 17025:2000, and ANSI/NCSL Z540-1 (equivalent to ISO Guide 25). FM&T Metrology laboratories are accredited by NVLAP for the parameters, ranges, and uncertainties listed in the specific scope of accreditation under NVLAP Lab code 200108-0. See the Internet at http://ts.nist.gov/ts/htdocs/210/214/scopes/2001080.pdf. These parameters are summarized in the table at the bottom of this introduction.

  7. Graphene-based frequency tripler.

    Science.gov (United States)

    Chen, Hong-Yan; Appenzeller, Joerg

    2012-04-11

    Graphene has captured the imagination of researchers worldwide as an ideal two-dimensional material with exceptional electrical transport properties. The high electron and hole mobility quickly inspired scientists to search for electronic applications that require high-performance channel materials. However, the absence of a bandgap in graphene immediately revealed itself in terms of ambipolar device characteristics and the nonexistence of a device off-state. The question is: How can the superior electronic properties of graphene be harvested while dealing appropriately with its unique characteristics rather than enforcing conventional device concepts? Here, we report a novel device idea, a graphene-based frequency tripler, an application that employs an innovative electrostatic doping approach and exploits the unique ambipolar behavior of graphene. © 2012 American Chemical Society

  8. Quantum metrology in coarsened measurement reference

    Science.gov (United States)

    Xie, Dong; Xu, Chunling; Wang, An Min

    2017-01-01

    We investigate the role of coarsened measurement reference, which originates from the coarsened reference time and basis, in quantum metrology. When the measurement is based on one common reference basis, the disadvantage of coarsened measurement can be removed by symmetry. Owing to the coarsened reference basis, the entangled state cannot perform better than the product state for a large number of probe particles in estimating the phase. Given a finite uncertainty of the coarsened reference basis, the optimal number of probe particles is obtained. Finally, we prove that the maximally entangled state always achieves better frequency precision in the case of non-Markovian dephasing than that in the case of Markovian dephasing. The product state is more resistant to the interference of the coarsened reference time than the entangled state.

  9. The correction of vibration in frequency scanning interferometry based absolute distance measurement system for dynamic measurements

    Science.gov (United States)

    Lu, Cheng; Liu, Guodong; Liu, Bingguo; Chen, Fengdong; Zhuang, Zhitao; Xu, Xinke; Gan, Yu

    2015-10-01

    Absolute distance measurement systems are of significant interest in the field of metrology, which could improve the manufacturing efficiency and accuracy of large assemblies in fields such as aircraft construction, automotive engineering, and the production of modern windmill blades. Frequency scanning interferometry demonstrates noticeable advantages as an absolute distance measurement system which has a high precision and doesn't depend on a cooperative target. In this paper , the influence of inevitable vibration in the frequency scanning interferometry based absolute distance measurement system is analyzed. The distance spectrum is broadened as the existence of Doppler effect caused by vibration, which will bring in a measurement error more than 103 times bigger than the changes of optical path difference. In order to decrease the influence of vibration, the changes of the optical path difference are monitored by a frequency stabilized laser, which runs parallel to the frequency scanning interferometry. The experiment has verified the effectiveness of this method.

  10. Quantum resistance metrology using graphene.

    Science.gov (United States)

    Janssen, T J B M; Tzalenchuk, A; Lara-Avila, S; Kubatkin, S; Fal'ko, V I

    2013-10-01

    In this paper, we review the recent extraordinary progress in the development of a new quantum standard for resistance based on graphene. We discuss the unique properties of this material system relating to resistance metrology and discuss results of the recent highest-ever precision direct comparison of the Hall resistance between graphene and traditional GaAs. We mainly focus our review on graphene expitaxially grown on SiC, a system which so far resulted in the best results. We also briefly discuss progress in the two other graphene material systems, exfoliated graphene and chemical vapour deposition graphene, and make a critical comparison with SiC graphene. Finally, we discuss other possible applications of graphene in metrology.

  11. Metrology Measurement Capabilities

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Glen E. Gronniger

    2007-10-02

    This document contains descriptions of Federal Manufacturing & Technologies (FM&T) Metrology capabilities, traceability flow charts, and the measurement uncertainty of each measurement capability. Metrology provides NIST traceable precision measurements or equipment calibration for a wide variety of parameters, ranges, and state-of-the-art uncertainties. Metrology laboratories conform to the requirements of the Department of Energy Development and Production Manual Chapter 13.2, ANSI/ISO/IEC ANSI/ISO/IEC 17025:2005, and ANSI/NCSL Z540-1. FM&T Metrology laboratories are accredited by NVLAP for the parameters, ranges, and uncertainties listed in the specific scope of accreditation under NVLAP Lab code 200108-0. See the Internet at http://ts.nist.gov/Standards/scopes/2001080.pdf. These parameters are summarized. The Honeywell Federal Manufacturing & Technologies (FM&T) Metrology Department has developed measurement technology and calibration capability in four major fields of measurement: (1) Mechanical; (2) Environmental, Gas, Liquid; (3) Electrical (DC, AC, RF/Microwave); and (4) Optical and Radiation. Metrology Engineering provides the expertise to develop measurement capabilities for virtually any type of measurement in the fields listed above. A strong audit function has been developed to provide a means to evaluate the calibration programs of our suppliers and internal calibration organizations. Evaluation includes measurement audits and technical surveys.

  12. Metrology at Philip Morris Europe

    Directory of Open Access Journals (Sweden)

    Gualandris R

    2014-12-01

    Full Text Available The importance of the metrology function at Philip Morris Europe (PME, a multinational organisation producing at over 40 sites in the European, Middle Eastern and African Regions is presented. Standardisation of test methods and equipment as well as the traceability of calibration gauges to the same reference gauge are essential in order to obtain comparable results among the various production centers. The metrology function as well as the qualification of instruments and the drafting of test and calibration operating procedures for this region are conducted or co-ordinated by the Research and Development Department in Neuchatel, Switzerland. In this paper the metrology function within PME is presented based on the measurement of the resistance to draw for which the PME R&D laboratory is accredited (ISO/CEI 17025, as both a calibration and a testing laboratory. The following topics are addressed in this paper: traceability of calibration standards to national standards; comparison of results among manufacturing centres; the choice, the budget as well as the computation of uncertainties. Furthermore, some practical aspects related to the calibration and use of the glass multicapillary gauges are discussed.

  13. Metrology For Emerging Research Materials And Devices

    Science.gov (United States)

    Garner, C. Michael; Herr, Dan

    2007-09-01

    The International Technology Roadmap for Semiconductors (ITRS) [1] identifies a number of potentially enabling device and materials technologies to extend and compliment CMOS. These emerging memory and logic devices employ alternate "states" including 1D charge state, molecular state, polarization, material phase, and spin. The improvement of these materials and devices depends on utilizing existing and new metrology methods to characterize their structure, composition and emerging critical properties at the nanometer scale. The metrology required to characterize nanomaterials, interfaces, and device structures will include existing structural metrology, such as TEM, SEM, and others, as well as metrology to characterize new "state" properties of the materials. The characterization of properties and correlations to nanostructure and composition are critical for these new devices and materials. Characterizing the properties of emerging logic technologies will be very difficult, as an applied stimulus is required to probe dynamic state changes. In many cases, it will be important simultaneously to measure the spatial variation of multiple state properties, such as charge and spin, as a function of time at high frequencies to develop an understanding of the interactions occurring in the materials and at interfaces. Furthermore, the challenge of characterizing interface structure/composition and "state" interactions likely will increase with device scaling. New metrology capabilities are needed to study the static and dynamic properties of potential alternate "state" materials and devices at small dimensions.

  14. PREFACE: VII Brazilian Congress on Metrology (Metrologia 2013)

    Science.gov (United States)

    Costa-Félix, Rodrigo; Bernardes, Americo; Valente de Oliveira, José Carlos; Mauro Granjeiro, José; Epsztejn, Ruth; Ihlenfeld, Waldemar; Smarçaro da Cunha, Valnei

    2015-01-01

    SEVENTH BRAZILIAN CONGRESS ON METROLOGY (METROLOGIA 2013) Metrology and Quality for a Sustainable Development From November 24th to 27th 2013 was issued the Seventh Brazilian Congress on Metrology (Metrologia 2013), which is a biannual conference organized and sponsored by the Brazilian Society of Metrology (SBM) and the Brazilian National Institute of Metrology, Quality and Technology (Inmetro). This edition was held in the charming and historical city of Ouro Preto, MG, Brazil, and aimed to join people and institutions devoted to the dissemination of the metrology and conformity assessment. The Metrologia 2013 Conference consisted of Keynote Speeches (7) and regular papers (204). Among the regular papers, the 47 most outstanding ones, comprising a high quality content on Metrology and Conformity Assessment, were selected to be published in this issue of the Journal of Physics: Conference Series. The topics of the conference covered all important areas of Metrology, which were agglutinated in the following sessions in the present issue: . Physical Metrology (Acoustics, Vibration and Ultrasound; Electricity and Magnetism; Mechanics; Optics); . Metrology on Ionizing Radiations; . Time and Frequency; . Chemistry Metrology; . Materials Metrology; . Biotechnology; . Uncertainty, Statistics and Mathematics; . Legal Metrology; . Conformity Assessment. It is our great pleasure to present this volume of IOP Journal of Physics: Conference Series (JPCS) to the scientific community to promote further research in Metrology and related areas. We believe that this volume will be both an excellent source of scientific material in the fast evolving fields that were covered by Metrologia 2013. President of the congress Americo Bernardes Federal University of Ouro Preto atb@iceb.ufop.br Editor-in-chief Rodrigo Costa-Félix Brazilian National Institute of Metrology, Quality and Technology rpfelix@inmetro.gov.br Editors José Carlos Valente de Oliveira (Editor on Mechanical Metrology

  15. Wafer-shape based in-plane distortion predictions using superfast 4G metrology

    Science.gov (United States)

    van Dijk, Leon; Mileham, Jeffrey; Malakhovsky, Ilja; Laidler, David; Dekkers, Harold; Van Elshocht, Sven; Anberg, Doug; Owen, David M.; van Haren, Richard

    2017-03-01

    With the latest immersion scanners performing at the sub-2 nm overlay level, the non-lithography contributors to the OnProduct-Overlay budget become more and more dominant. Examples of these contributors are etching, thin film deposition, Chemical-Mechanical Planarization and thermal anneal. These processes can introduce stress or stress changes in the thin films on top of the silicon wafers, resulting in significant wafer grid distortions. High-order wafer alignment (HOWA) is the current ASML solution for correcting wafers with a high order grid distortion introduced by non-lithographic processes, especially when these distortions vary from wafer-to-wafer. These models are currently successfully applied in high volume production at several semiconductor device manufacturers. An important precondition is that the wafer distortions remain global as the polynomial-based HOWA models become less effective for very local distortions. Wafer-shape based feed forward overlay corrections can be a possible solution to overcome this challenge. Thin film stress typically has an impact on the unclamped, free-form shape of the wafers. When an accurate relationship between the wafer shape and in-plane distortion (IPD) after clamping is established then feedforward overlay control can be enabled. In this work we assess the capability of wafer-shape based IPD predictions via a controlled experiment. The processinduced IPDs are accurately measured on the ASML TWINSCANTM system using its SMASH alignment system and the wafer shapes are measured on the Superfast 4G inspection system. In order to relate the wafer shape to the IPD we have developed a prediction model beyond the standard Stoney approximation. The match between the predicted and measured IPD is excellent ( 1-nm), indicating the feasibility of using wafer shape for feed-forward overlay control.

  16. Development of at-wavelength metrology using grating-based shearing interferometry at Diamond Light Source

    Science.gov (United States)

    Wang, Hongchang; Berujon, Sebastien; Sawhney, Kawal

    2013-03-01

    The grating-based shearing interferometer has been established and further developed on B16 at Diamond Light Source. The beamline performances of both an X-ray plane mirror and a compound refractive lens (CRL) have been investigated using this technique. The slope error of the X-ray mirror was retrieved from the wavefront phase gradient, which was measured using two different processing schemes: phase stepping and moiré fringe analysis. The interferometer has demonstrated a high sensitivity with sub-microradian accuracy. Some of the advantages, disadvantages and limitations for the two approaches will also be presented.

  17. Adaptive automatic data analysis in full-field fringe-pattern-based optical metrology

    Science.gov (United States)

    Trusiak, Maciej; Patorski, Krzysztof; Sluzewski, Lukasz; Pokorski, Krzysztof; Sunderland, Zofia

    2016-12-01

    Fringe pattern processing and analysis is an important task of full-field optical measurement techniques like interferometry, digital holography, structural illumination and moiré. In this contribution we present several adaptive automatic data analysis solutions based on the notion of Hilbert-Huang transform for measurand retrieval via fringe pattern phase and amplitude demodulation. The Hilbert-Huang transform consists of 2D empirical mode decomposition algorithm and Hilbert spiral transform analysis. Empirical mode decomposition adaptively dissects a meaningful number of same-scale subimages from the analyzed pattern - it is a data-driven method. Appropriately managing this set of unique subimages results in a very powerful fringe pre-filtering tool. Phase/amplitude demodulation is performed using Hilbert spiral transform aided by the local fringe orientation estimator. We describe several optical measurement techniques for technical and biological objects characterization basing on the especially tailored Hilbert-Huang algorithm modifications for fringe pattern denoising, detrending and amplitude/phase demodulation.

  18. CSAM Metrology Software Tool

    Science.gov (United States)

    Vu, Duc; Sandor, Michael; Agarwal, Shri

    2005-01-01

    CSAM Metrology Software Tool (CMeST) is a computer program for analysis of false-color CSAM images of plastic-encapsulated microcircuits. (CSAM signifies C-mode scanning acoustic microscopy.) The colors in the images indicate areas of delamination within the plastic packages. Heretofore, the images have been interpreted by human examiners. Hence, interpretations have not been entirely consistent and objective. CMeST processes the color information in image-data files to detect areas of delamination without incurring inconsistencies of subjective judgement. CMeST can be used to create a database of baseline images of packages acquired at given times for comparison with images of the same packages acquired at later times. Any area within an image can be selected for analysis, which can include examination of different delamination types by location. CMeST can also be used to perform statistical analyses of image data. Results of analyses are available in a spreadsheet format for further processing. The results can be exported to any data-base-processing software.

  19. A Century of Acoustic Metrology

    DEFF Research Database (Denmark)

    Rasmussen, Knud

    1998-01-01

    The development in acoustic measurement technique over the last century is reviewed with special emphasis on the metrological aspect.......The development in acoustic measurement technique over the last century is reviewed with special emphasis on the metrological aspect....

  20. Metrology of microcomponents and nanostructures

    DEFF Research Database (Denmark)

    Bariani, Paolo

    2004-01-01

    OH presentation at Conference on "Optical Coordinate Metrology, 3D Digitisation and Reverse Engineering", DTU, 28. oktober 2004......OH presentation at Conference on "Optical Coordinate Metrology, 3D Digitisation and Reverse Engineering", DTU, 28. oktober 2004...

  1. Metrology of microcomponents and nanostructures

    DEFF Research Database (Denmark)

    Bariani, Paolo

    2004-01-01

    OH presentation at Conference on "Optical Coordinate Metrology, 3D Digitisation and Reverse Engineering", DTU, 28. oktober 2004......OH presentation at Conference on "Optical Coordinate Metrology, 3D Digitisation and Reverse Engineering", DTU, 28. oktober 2004...

  2. Coherent double-color interference microscope for traceable optical surface metrology

    Science.gov (United States)

    Malinovski, I.; França, R. S.; Bessa, M. S.; Silva, C. R.; Couceiro, I. B.

    2016-06-01

    Interference microscopy is an important field of dimensional surface metrology because it provides direct traceability of the measurements to the SI base unit definition of the metre. With a typical measurement range from micrometres to nanometres interference microscopy (IM) covers the gap between classic metrology and nanometrology, providing continuous transfer of dimensional metrology into new areas of nanoscience and nanotechnology. Therefore IM is considered to be an indispensable tool for traceable transfer of the metre unit to different instruments. We report here the metrological study of an absolute Linnik interference microscope (IM) based on two frequency stabilized lasers. The design permits the flexible use of both lasers for measurements depending on the demand of the concrete measurement task. By principle of operation IM is combination of imaging and phase-shifting interferometry (PSI). The traceability is provided by the wavelength reference, that is, a He-Ne 633 nm stabilized laser. The second laser source, that is, a Blue-Green 488 nm grating stabilized laser diode, is used for improvements of resolution, and also for resolving integer fringe discontinuities on sharp features of the surface. The IM was optimized for surface height metrology. We have performed the study of the systematic effects of the measurements. This study allowed us to improve the hardware and software of IM and to find corrections for main systematic errors. The IM is purposed for 1D to 3D height metrology and surface topography in an extended range from nanometres to micrometres. The advantages and disadvantages of the design and developed methods are discussed.

  3. Fringe pattern analysis for optical metrology theory, algorithms, and applications

    CERN Document Server

    Servin, Manuel; Padilla, Moises

    2014-01-01

    The main objective of this book is to present the basic theoretical principles and practical applications for the classical interferometric techniques and the most advanced methods in the field of modern fringe pattern analysis applied to optical metrology. A major novelty of this work is the presentation of a unified theoretical framework based on the Fourier description of phase shifting interferometry using the Frequency Transfer Function (FTF) along with the theory of Stochastic Process for the straightforward analysis and synthesis of phase shifting algorithms with desired properties such

  4. Metrology Measurement Capabilities

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, L.M.

    2000-03-23

    This document contains descriptions of Federal Manufacturing and Technologies (FM and T) Metrology capabilities, traceability flow charts, and the measurement uncertainty of each measurement capability. Metrology provides NIST traceable precision measurements or equipment calibration for a wide variety of parameters, ranges, and state-of-the-art uncertainties in laboratories that conform to the requirements of the Department of Energy Development and Production Manual Chapter 8.4, and ANSI/NCSL Z540-1 (equivalent to ISO Guide 25). FM and T Metrology laboratories are accredited by NVLAP for the parameters, ranges, and uncertainties listed in the specific scope of accreditation under NVLAP Lab code 200108-0. These parameters are summarized.

  5. Optical imaging and metrology

    CERN Document Server

    Osten, Wolfgang

    2012-01-01

    A comprehensive review of the state of the art and advances in the field, while also outlining the future potential and development trends of optical imaging and optical metrology, an area of fast growth with numerous applications in nanotechnology and nanophysics. Written by the world's leading experts in the field, it fills the gap in the current literature by bridging the fields of optical imaging and metrology, and is the only up-to-date resource in terms of fundamental knowledge, basic concepts, methodologies, applications, and development trends.

  6. Metrology for drug delivery.

    Science.gov (United States)

    Lucas, Peter; Klein, Stephan

    2015-08-01

    In various recently published studies, it is argued that there are underestimated risks with infusion technology, i.e., adverse incidents believed to be caused by inadequate administration of the drugs. This is particularly the case for applications involving very low-flow rates, i.e., metrological infrastructure for low-flow rates. Technical challenges such as these were the reason a European research project "Metrology for Drug Delivery" was started in 2011. In this special issue of Biomedical Engineering, the results of that project are discussed.

  7. Hybrid photonic chip interferometer for embedded metrology

    Science.gov (United States)

    Kumar, P.; Martin, H.; Maxwell, G.; Jiang, X.

    2014-03-01

    Embedded metrology is the provision of metrology on the manufacturing platform, enabling measurement without the removal of the work piece. Providing closer integration of metrology upon the manufacturing platform can lead to the better control and increased throughput. In this work we present the development of a high precision hybrid optical chip interferometer metrology device. The complete metrology sensor system is structured into two parts; optical chip and optical probe. The hybrid optical chip interferometer is based on a silica-on-silicon etched integrated-optic motherboard containing waveguide structures and evanescent couplers. Upon the motherboard, electro-optic components such as photodiodes and a semiconductor gain block are mounted and bonded to provide the required functionality. The key structure in the device is a tunable laser module based upon an external-cavity diode laser (ECDL). Within the cavity is a multi-layer thin film filter which is rotated to select the longitudinal mode at which the laser operates. An optical probe, which uses a blazed diffracting grating and collimating objective lens, focuses light of different wavelengths laterally over the measurand. Incident laser light is then tuned in wavelength time to effectively sweep an `optical stylus' over the surface. Wavelength scanning and rapid phase shifting can then retrieve the path length change and thus the surface height. We give an overview of the overall design of the final hybrid photonic chip interferometer, constituent components, device integration and packaging as well as experimental test results from the current version now under evaluation.

  8. Differential Evolution for Many-Particle Adaptive Quantum Metrology

    NARCIS (Netherlands)

    Lovett, N.B.; Crosnier, C.; Perarnau- Llobet, M.; Sanders, B.

    2013-01-01

    We devise powerful algorithms based on differential evolution for adaptive many-particle quantum metrology. Our new approach delivers adaptive quantum metrology policies for feedback control that are orders-of-magnitude more efficient and surpass the few-dozen-particle limitation arising in methods

  9. Takagi-Sugeno model based analysis of EWMA RtR control of batch processes with stochastic metrology delay and mixed products.

    Science.gov (United States)

    Zheng, Ying; Wong, David Shan-Hill; Wang, Yan-Wei; Fang, Huajing

    2014-07-01

    In many batch-based industrial manufacturing processes, feedback run-to-run control is used to improve production quality. However, measurements may be expensive and cannot always be performed online. Thus, the measurement delay always exists. The metrology delay will affect the stability and performance of the process. Moreover, since quality measurements are performed offline, delay is not fixed but is stochastic in nature. In this paper, a modeling approach Takagi-Sugeno (T-S) model is presented to handle stochastic metrology delay in both single-product and mixed-product processes. Based on the Markov characteristics of the delay, the membership of the T-S model is derived. Performance indices such as the mean and the variance of the closed-loop output of the exponentially weighted moving average (EWMA) control algorithm can be derived. A steady-state error of the process output always exists, which leads the output deviating from the target. To remove the steady-state error, an algorithm called compensatory EWMA run-to-run (COM-EWMA-RtR) algorithm is proposed. The validity of the T-S model analysis and the efficiency of the proposed COM-EWMA-RtR algorithm are confirmed by simulation.

  10. Metrological Characterization of an Improved DSP-Based On-line Integrator for Magnetic Measurements at CERN

    CERN Document Server

    Arpaia, P; Spiezia, G

    2007-01-01

    An improved on-line version of the self-calibrating digital instrument for flux measurements on superconductive magnets for particle accelerators, prototyped at the European Organization for Nuclear Research (CERN) in cooperation with the University of Sannio, is proposed. The instrument acquires voltage arising from rotating coils transducers. Then, the samples are online integrated and suitably processed in order to achieve flux analysis time down to 2.0 ìs, with resolution of 50 ns. Details about hardware and firmware conception, on-line measurement principle, and preliminary results of metrological characterization of the prototype are provided.

  11. Frontier and Evolution of Marketing Discipline Based on Scientific Metrological Analysis of Top 4 Marketing Periodicals in 2009-2013

    Institute of Scientific and Technical Information of China (English)

    Shenpeng ZHANG

    2015-01-01

    Using scientific metrological method,this paper analyzed all literature published by top 4 marketing periodicals( JCR,JM,JMR,and MS) in 2009- 2013. It is intended to find out hot issues and frontier topics of current marketing research through cluster analysis of key words,get to know cooperation and exchange of organizations through analysis of organization cooperative network,explore new topics of marketing researches with the aid of analysis of abrupt change words,and explore evolution path and development rules of marketing researches through co-citation network analysis.

  12. Overview of Mask Metrology

    Science.gov (United States)

    Rice, Bryan J.; Jindal, Vibhu; Lin, C. C.; Harris-Jones, Jenah; Kwon, Hyuk Joo; Ma, Hsing-Chien; Goldstein, Michael; Chan, Yau-Wai; Goodwin, Frank

    2011-11-01

    Extreme ultraviolet (EUV) lithography is the successor to optical lithography and will enable advanced patterning in semiconductor manufacturing processes down to the 8 nm half pitch technology node and beyond. However, before EUV can successfully be inserted into high volume manufacturing a few challenges must be overcome. Central among these remaining challenges is the requirement to produce "defect free" EUV masks. Mask blank defects have been one of the top challenges in the commercialization of extreme ultraviolet (EUV) lithography. To determine defect sources and devise mitigation solutions, detailed characterization of defects is critical. However, small defects pose challenges in metrology scale-up. SEMATECH has a comprehensive metrology strategy to address any defect larger than a 20 nm core size to obtain solutions for defect-free EUV mask blanks. SEMATECH's Mask Blank Development Center has been working since 2003 to develop the technology to support defect free EUV mask blanks. Since 2003, EUV mask blank defects have been reduced from 10000 of size greater than 100 nm to about a few tens at size 70 nm. Unfortunately, today's state of the art defect levels are still about 10 to 100 times higher than needed. Closing this gap requires progress in the various processes associated with glass substrate creation and multilayer deposition. That process development improvement in turn relies upon the availability of metrology equipment that can resolve and chemically characterize defects as small as 30 nm. The current defect reduction efforts at SEMATECH have intensively included a focus on inspection and characterization. The facility boasts nearly 100M of metrology hardware, including an FEI Titan TEM, Lasertec M1350 and M7360 tools, an actinic inspection tool, AFM, SPM, and scanning auger capabilities. The newly established Auger tool at SEMATECH can run a standard 6-inch mask blank and is already providing important information on sub-100 nm defects on EUV

  13. Note: Near infrared interferometric silicon wafer metrology.

    Science.gov (United States)

    Choi, M S; Park, H M; Joo, K N

    2016-04-01

    In this investigation, two near infrared (NIR) interferometric techniques for silicon wafer metrology are described and verified with experimental results. Based on the transparent characteristic of NIR light to a silicon wafer, the fiber based spectrally resolved interferometry can measure the optical thickness of the wafer and stitching low coherence scanning interferometry can reconstruct entire surfaces of the wafer.

  14. Mid-Infrared Optical Frequency Combs based on Crystalline Microresonators

    CERN Document Server

    Wang, C Y; Del'Haye, P; Schliesser, A; Hofer, J; Holzwarth, R; Hänsch, T W; Picqué, N; Kippenberg, T J

    2011-01-01

    The mid-infrared spectral range (\\lambda ~ 2 \\mu m to 20 \\mu m) is known as the "molecular fingerprint" region as many molecules have their highly characteristic, fundamental ro-vibrational bands in this part of the electromagnetic spectrum. Broadband mid-infrared spectroscopy therefore constitutes a powerful and ubiquitous tool for optical analysis of chemical components that is used in biochemistry, astronomy, pharmaceutical monitoring and material science. Optical frequency combs, i.e. broad spectral bandwidth coherent light sources consisting of equally spaced sharp lines, have revolutionized optical frequency metrology one decade ago. They now demonstrate dramatically improved acquisition rates, resolution and sensitivity for molecular spectroscopy mostly in the visible and near-infrared ranges. Mid-infrared frequency combs have therefore become highly desirable and recent progress in generating such combs by nonlinear frequency conversion has opened access to this spectral region. Here we report on a pr...

  15. Advances in speckle metrology and related techniques

    CERN Document Server

    Kaufmann, Guillermo H

    2010-01-01

    Speckle metrology includes various optical techniques that are based on the speckle fields generated by reflection from a rough surface or by transmission through a rough diffuser. These techniques have proven to be very useful in testing different materials in a non-destructive way. They have changed dramatically during the last years due to the development of modern optical components, with faster and more powerful digital computers, and novel data processing approaches. This most up-to-date overview of the topic describes new techniques developed in the field of speckle metrology over the l

  16. Silicon-Chip-Based Optical Frequency Combs

    Science.gov (United States)

    2015-10-26

    frequencies . This phenomenon appears in many systems spanning biology, chemistry, neuroscience, and physics [29,30]. Examples include power grid networks... Frequency Combs," Phys. Rev. Lett. 100, 013902 (2008). [91] F. Leo, et al., “Dispersive wave emission and supercontinuum generation in a silicon wire...AFRL-AFOSR-VA-TR-2015-0365 Silicon-Chip-Based Optical Frequency Combs Alexander Gaeta CORNELL UNIVERSITY Final Report 10/26/2015 DISTRIBUTION A

  17. Process window metrology

    Science.gov (United States)

    Ausschnitt, Christopher P.; Chu, William; Hadel, Linda M.; Ho, Hok; Talvi, Peter

    2000-06-01

    This paper is the third of a series that defines a new approach to in-line lithography control. The first paper described the use of optically measurable line-shortening targets to enhance signal-to-noise and reduce measurement time. The second described the dual-tone optical critical dimension (OCD) measurement and analysis necessary to distinguish dose and defocus. Here we describe the marriage of dual-tone OCD to SEM-CD metrology that comprises what we call 'process window metrology' (PWM), the means to locate each measured site in dose and focus space relative to the allowed process window. PWM provides in-line process tracking and control essential to the successful implementation of low-k lithography.

  18. Metrology and Time

    CERN Document Server

    Rybak, B

    1999-01-01

    The algorithm Pi/sinx reveals an elliptic excess which acts as the real component (Space) inducing the imaginary component (Time). Key words : metrology, chronogenesis, tropic year, anomalistic year. ----- L 'algorithme Pi/sinx revele un excedent elliptique constituant la composante active d ' espace dont la composante reactive exprime la chronogenese tropique aussi bien qu ' anomalistique.. Mots-cles : metrologie, chronogenese, annee tropique, annee anomalistique

  19. Multi-dimensional, non-contact metrology using trilateration and high resolution FMCW ladar.

    Science.gov (United States)

    Mateo, Ana Baselga; Barber, Zeb W

    2015-07-01

    Here we propose, describe, and provide experimental proof-of-concept demonstrations of a multidimensional, non-contact-length metrology system design based on high resolution (millimeter to sub-100 micron) frequency modulated continuous wave (FMCW) ladar and trilateration based on length measurements from multiple, optical fiber-connected transmitters. With an accurate FMCW ladar source, the trilateration-based design provides 3D resolution inherently independent of standoff range and allows self-calibration to provide flexible setup of a field system. A proof-of-concept experimental demonstration was performed using a highly stabilized, 2 THz bandwidth chirped laser source, two emitters, and one scanning emitter/receiver providing 1D surface profiles (2D metrology) of diffuse targets. The measured coordinate precision of <200 microns was determined to be limited by laser speckle issues caused by diffuse scattering of the targets.

  20. Status of the Metrology Light Source

    Science.gov (United States)

    Klein, R.; Ulm, G.; Feikes, J.; Hartrott, M. v.; Wüstefeld, G.

    2010-06-01

    The Physikalisch-Technische Bundesanstalt (PTB), the German national metrology institute, has set up the low-energy electron storage ring Metrology Light Source (MLS) in close cooperation with the Helmholtz-Zentrum Berlin (HZB, formerly BESSY). This new storage ring has been in regular user operation since April 2008 and is dedicated to synchrotron-radiation-based metrology and technological developments in the far-IR/THz, IR, UV, VUV and EUV spectral range. The MLS has a double-bend-achromate lattice structure, injection is from a 105 MeV racetrack microtron. The electron energy can be ramped to any value from 105 MeV up to 630 MeV and the electron beam current covers the range from one stored electron (1 pA) up to 200 mA. The MLS is the first electron storage ring optimized for the generation of coherent synchrotron radiation, based on an electron bunch shortening mode. In this mode, MLS delivers coherent radiation in the far-IR/THz spectral range with enhanced intensity as compared to the normal mode of operation. Several beamlines are in operation or in construction, including one undulator beamline, bending magnet beamlines for the calibration of radiation sources and detectors and for reflectometry, an EUV metrology beamline and three IR/THz beamlines.

  1. Quantum metrology with cold atomic ensembles

    Directory of Open Access Journals (Sweden)

    Mitchell Morgan W.

    2013-08-01

    Full Text Available Quantum metrology uses quantum features such as entanglement and squeezing to improve the sensitivity of quantum-limited measurements. Long established as a valuable technique in optical measurements such as gravitational-wave detection, quantum metrology is increasingly being applied to atomic instruments such as matter-wave interferometers, atomic clocks, and atomic magnetometers. Several of these new applications involve dual optical/atomic quantum systems, presenting both new challenges and new opportunities. Here we describe an optical magnetometry system that achieves both shot-noise-limited and projection-noise-limited performance, allowing study of optical magnetometry in a fully-quantum regime [1]. By near-resonant Faraday rotation probing, we demonstrate measurement-based spin squeezing in a magnetically-sensitive atomic ensemble [2-4]. The versatility of this system allows us also to design metrologically-relevant optical nonlinearities, and to perform quantum-noise-limited measurements with interacting photons. As a first interaction-based measurement [5], we implement a non-linear metrology scheme proposed by Boixo et al. with the surprising feature of precision scaling better than the 1/N “Heisenberg limit” [6].

  2. Development of facilities and methods for the metrological characterization of distributed temperature sensing systems based on optical fibres

    Science.gov (United States)

    Failleau, G.; Beaumont, O.; Delepine-Lesoille, S.; Plumeri, S.; Razouk, R.; Beck, Y. L.; Hénault, J. M.; Bertrand, J.; Hay, B.

    2017-01-01

    Raman distributed temperature sensing (DTS) technologies are currently under evaluation by the nuclear and hydraulic industries as it may bring promising alternatives to classical measurement techniques. The reliability of the DTS measurements, as well as the traceability to the temperature standards, must be ensured throughout the entire period of monitoring (typically over a few tens of years). In order to achieve this goal, one key task consists in the verification of the performances claimed by the DTS devices manufacturers. Thus, the metrological performances and characteristics of the DTS devices, such as their limitations and accuracies, as well as the practical aspects of systems implemented on site should be evaluated step by step. This paper describes the dedicated facilities which have been developed at LNE in order to evaluate and to qualify DTS devices for very demanding applications. A first case study performed on one specific DTS device is detailed. A systematic bias has been observed among others on the spatial resolution. The DTS response to a temperature variation step over 1 m (spatial resolution typically claimed by the manufacturers) of sensing optical fibre corresponds indeed to only 90% of the temperature step magnitude, whereas the full DTS response is obtained in fact for 10 m (the practical spatial resolution) of sensing optical fibre solicited by this temperature step variation.

  3. IT Security Standards and Legal Metrology - Transfer and Validation

    Science.gov (United States)

    Thiel, F.; Hartmann, V.; Grottker, U.; Richter, D.

    2014-08-01

    Legal Metrology's requirements can be transferred into the IT security domain applying a generic set of standardized rules provided by the Common Criteria (ISO/IEC 15408). We will outline the transfer and cross validation of such an approach. As an example serves the integration of Legal Metrology's requirements into a recently developed Common Criteria based Protection Profile for a Smart Meter Gateway designed under the leadership of the Germany's Federal Office for Information Security. The requirements on utility meters laid down in the Measuring Instruments Directive (MID) are incorporated. A verification approach to check for meeting Legal Metrology's requirements by their interpretation through Common Criteria's generic requirements is also presented.

  4. Overlay metrology for double patterning processes

    Science.gov (United States)

    Leray, Philippe; Cheng, Shaunee; Laidler, David; Kandel, Daniel; Adel, Mike; Dinu, Berta; Polli, Marco; Vasconi, Mauro; Salski, Bartlomiej

    2009-03-01

    The double patterning (DPT) process is foreseen by the industry to be the main solution for the 32 nm technology node and even beyond. Meanwhile process compatibility has to be maintained and the performance of overlay metrology has to improve. To achieve this for Image Based Overlay (IBO), usually the optics of overlay tools are improved. It was also demonstrated that these requirements are achievable with a Diffraction Based Overlay (DBO) technique named SCOLTM [1]. In addition, we believe that overlay measurements with respect to a reference grid are required to achieve the required overlay control [2]. This induces at least a three-fold increase in the number of measurements (2 for double patterned layers to the reference grid and 1 between the double patterned layers). The requirements of process compatibility, enhanced performance and large number of measurements make the choice of overlay metrology for DPT very challenging. In this work we use different flavors of the standard overlay metrology technique (IBO) as well as the new technique (SCOL) to address these three requirements. The compatibility of the corresponding overlay targets with double patterning processes (Litho-Etch-Litho-Etch (LELE); Litho-Freeze-Litho-Etch (LFLE), Spacer defined) is tested. The process impact on different target types is discussed (CD bias LELE, Contrast for LFLE). We compare the standard imaging overlay metrology with non-standard imaging techniques dedicated to double patterning processes (multilayer imaging targets allowing one overlay target instead of three, very small imaging targets). In addition to standard designs already discussed [1], we investigate SCOL target designs specific to double patterning processes. The feedback to the scanner is determined using the different techniques. The final overlay results obtained are compared accordingly. We conclude with the pros and cons of each technique and suggest the optimal metrology strategy for overlay control in double

  5. Optical vortex metrology for non-destructive testing

    DEFF Research Database (Denmark)

    Wang, W.; Hanson, Steen Grüner

    2009-01-01

    Based on the phase singularities in optical fields, we introduce a new technique, referred to as Optical Vortex Metrology, and demonstrate its application to nano- displacement, flow measurements and biological kinematic analysis.......Based on the phase singularities in optical fields, we introduce a new technique, referred to as Optical Vortex Metrology, and demonstrate its application to nano- displacement, flow measurements and biological kinematic analysis....

  6. Metrology applied to ultrasound characterization of trabecular bones using the AIB parameter

    Science.gov (United States)

    Braz, D. S.; Silva, C. E.; Alvarenga, A. V.; Junior, D. S.; Costa-Félix, R. P. B.

    2016-07-01

    Apparent Integrated Backscattering (AIB) presents correlation between Apparent Backscatter Transfer Function and the transducer bandwidth. Replicas of trabecular bones (cubes of 20 mm side length) created by 3D printing technique were characterized using AIB with a 2.25 MHz center frequency transducer. A mechanical scanning system was used to acquire multiple backscatter signals. An uncertainty model in measurement was proposed based on the Guide to the Expression of Uncertainty in Measurement. Initial AIB results are not metrologically reliable, presenting high measurement uncertainties (sample: 5_0.2032/AIB: -15.1 dB ± 13.9 dB). It is noteworthy that the uncertainty model proposed contributes as unprecedented way for metrological assessment of trabecular bone characterization using AIB.

  7. Hybrid enabled thin film metrology using XPS and optical

    Science.gov (United States)

    Vaid, Alok; Iddawela, Givantha; Mahendrakar, Sridhar; Lenahan, Michael; Hossain, Mainul; Timoney, Padraig; Bello, Abner F.; Bozdog, Cornel; Pois, Heath; Lee, Wei Ti; Klare, Mark; Kwan, Michael; Kang, Byung Cheol; Isbester, Paul; Sendelbach, Matthew; Yellai, Naren; Dasari, Prasad; Larson, Tom

    2016-03-01

    Complexity of process steps integration and material systems for next-generation technology nodes is reaching unprecedented levels, the appetite for higher sampling rates is on the rise, while the process window continues to shrink. Current thickness metrology specifications reach as low as 0.1A for total error budget - breathing new life into an old paradigm with lower visibility for past few metrology nodes: accuracy. Furthermore, for advance nodes there is growing demand to measure film thickness and composition on devices/product instead of surrogate planar simpler pads. Here we extend our earlier work in Hybrid Metrology to the combination of X-Ray based reference technologies (high performance) with optical high volume manufacturing (HVM) workhorse metrology (high throughput). Our stated goal is: put more "eyes" on the wafer (higher sampling) and enable move to films on pattern structure (control what matters). Examples of 1X front-end applications are used to setup and validate the benefits.

  8. Advances in Quantum Metrology

    CERN Document Server

    Giovannetti, Vittorio; Maccone, Lorenzo

    2011-01-01

    In classical estimation theory, the central limit theorem implies that the statistical error in a measurement outcome can be reduced by an amount proportional to n^(-1/2) by repeating the measures n times and then averaging. Using quantum effects, such as entanglement, it is often possible to do better, decreasing the error by an amount proportional to 1/n. Quantum metrology is the study of those quantum techniques that allow one to gain advantages over purely classical approaches. In this review, we analyze some of the most promising recent developments in this research field. Specifically, we deal with the developments of the theory and point out some of the new experiments. Then we look at one of the main new trends of the field, the analysis of how the theory must take into account the presence of noise and experimental imperfections.

  9. Combining classical metrology models

    Directory of Open Access Journals (Sweden)

    Francisco Roldán

    2013-11-01

    Full Text Available The results obtained in the graphic analysis of the modulation of the Cuarto Real de Santo Domingo building in Granada, Spain, (ROLDÁN, 2011 have provided new insights to further approach the research on possible use the double-scale in historical monumental architecture. We propose the characterization of the singularities of the system, from the implications and graphic representation required by the metrological scheme identified, as well as the variety of typologies that are presented in their modular frames, and the iterative combination of two-scale modules which allow operational approximations to fractions and ratios not explicitly present in the system.

  10. Metrology with Unknown Detectors.

    Science.gov (United States)

    Altorio, Matteo; Genoni, Marco G; Somma, Fabrizia; Barbieri, Marco

    2016-03-11

    The best possible precision is one of the key figures in metrology, but this is established by the exact response of the detection apparatus, which is often unknown. There exist techniques for detector characterization that have been introduced in the context of quantum technologies but apply as well for ordinary classical coherence; these techniques, though, rely on intense data processing. Here, we show that one can make use of the simpler approach of data fitting patterns in order to obtain an estimate of the Cramér-Rao bound allowed by an unknown detector, and we present applications in polarimetry. Further, we show how this formalism provides a useful calculation tool in an estimation problem involving a continuous-variable quantum state, i.e., a quantum harmonic oscillator.

  11. Metrology with Unknown Detectors

    CERN Document Server

    Altorio, Matteo; Somma, Fabrizia; Barbieri, Marco

    2015-01-01

    The best possible precision is one of the key figures in metrology, but this is established by the exact response of the detection apparatus, which is often unknown. There exist techniques for detector characterisation, that have been introduced in the context of quantum technologies, but apply as well for ordinary classical coherence; these techniques, though, rely on intense data processing. Here we show that one can make use of the simpler approach of data fitting patterns in order to obtain an estimate of the Cram\\'er-Rao bound allowed by an unknown detector, and present applications in polarimetry. Further, we show how this formalism provide a useful calculation tool in an estimation problem involving a continuous-variable quantum state, i.e. a quantum harmonic oscillator.

  12. Talking about Metrology and Energy On World Metrology Day

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ The theme of this year's World Metrology Day is "Metrology and Energy". The energy problem is an important issue for the whole world and has received great attention in China since China is both a big energy-consuming country and a country severely short of energy.Under the energy and environmental pressure, China will take measures in the following four respects in order to solve the problem of energy shortage:

  13. Color and appearance metrology facility

    Data.gov (United States)

    Federal Laboratory Consortium — The NIST Physical Measurement Laboratory has established the color and appearance metrology facility to support calibration services for 0°/45° colored samples, 20°,...

  14. Metrology of IXO Mirror Segments

    Science.gov (United States)

    Chan, Kai-Wing

    2011-01-01

    For future x-ray astrophysics mission that demands optics with large throughput and excellent angular resolution, many telescope concepts build around assembling thin mirror segments in a Wolter I geometry, such as that originally proposed for the International X-ray Observatory. The arc-second resolution requirement posts unique challenges not just for fabrication, mounting but also for metrology of these mirror segments. In this paper, we shall discuss the metrology of these segments using normal incidence metrological method with interferometers and null lenses. We present results of the calibration of the metrology systems we are currently using, discuss their accuracy and address the precision in measuring near-cylindrical mirror segments and the stability of the measurements.

  15. Computed tomography for dimensional metrology

    DEFF Research Database (Denmark)

    Kruth, J.P.; Bartscher, M.; Carmignato, S.;

    2011-01-01

    metrology, putting emphasis on issues as accuracy, traceability to the unit of length (the meter) and measurement uncertainty. It provides a state of the art (anno 2011) and application examples, showing the aptitude of CT metrology to: (i) check internal dimensions that cannot be measured using traditional...... coordinate measuring machines and (ii) combine dimensional quality control with material quality control in one single quality inspection run....

  16. Quantum Metrology in Non-Markovian Environments

    CERN Document Server

    Chin, Alex W; Plenio, Martin B

    2011-01-01

    We analyze optimal bounds for precision spectroscopy in the presence of general, non-Markovian phase noise. We demonstrate that the metrological equivalence of product and maximally entangled states that holds under Markovian dephasing fails in the non-Markovian case. Using an exactly solvable model of a physically realistic finite band-width dephasing environment, we show that the ensuing non-Markovian dynamics enables quantum correlated states to outperform metrological strategies based on uncorrelated states but otherwise identical resources. We show that this conclusion is a direct result of the coherent dynamics of the global state of the system and environment and, as a result, possesses general validity that goes beyond specific models.

  17. Quantum metrology foundation of units and measurements

    CERN Document Server

    Goebel, Ernst O

    2015-01-01

    The International System of Units (SI) is the world's most widely used system of measurement, used every day in commerce and science, and is the modern form of the metric system. It currently comprises the meter (m), the kilogram (kg), the second (s), the ampere (A), the kelvin (K), the candela (cd) and the mole (mol)). The system is changing though, units and unit definitions are modified through international agreements as the technology of measurement progresses, and as the precision of measurements improves. The SI is now being redefined based on constants of nature and their realization by quantum standards. Therefore, the underlying physics and technologies will receive increasing interest, and not only in the metrology community but in all fields of science. This book introduces and explains the applications of modern physics concepts to metrology, the science and the applications of measurements. A special focus is made on the use of quantum standards for the realization of the forthcoming new SI (the...

  18. Advances in the atomic force microscopy for critical dimension metrology

    Science.gov (United States)

    Hussain, Danish; Ahmad, Khurshid; Song, Jianmin; Xie, Hui

    2017-01-01

    Downscaling, miniaturization and 3D staking of the micro/nano devices are burgeoning phenomena in the semiconductor industry which have posed sophisticated challenges in the critical dimension (CD) metrology. Over the past few years, atomic force microscopy (AFM) has emerged as an important CD metrology technique in meeting these challenges because of its high accuracy, 3D imaging capability, high spatial resolution and non-destructive nature. In this article, advances in the AFM based critical dimension (CD) metrology are systematically reviewed and discussed. CD metrology AFM techniques, strengths, limitations and scanning algorithms are described. Developments towards accurate measurements such as creep and hysteresis compensation of the piezoelectric scanners, their calibration and tip characterization are discussed. In addition, image reconstruction and measures for achieving high accuracy CD measurements with hybrid metrology technique are also discussed. CD metrology challenges offered by the next generation lithography (NGL) techniques such as those associated with the 3D nanodevices of 10 nm node and beyond have been highlighted.

  19. Frequency Based Fault Detection in Wind Turbines

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob

    2014-01-01

    In order to obtain lower cost of energy for wind turbines fault detection and accommodation is important. Expensive condition monitoring systems are often used to monitor the condition of rotating and vibrating system parts. One example is the gearbox in a wind turbine. This system is operated...... in parallel to the control system, using different computers and additional often expensive sensors. In this paper a simple filter based algorithm is proposed to detect changes in a resonance frequency in a system, exemplified with faults resulting in changes in the resonance frequency in the wind turbine...... gearbox. Only the generator speed measurement which is available in even simple wind turbine control systems is used as input. Consequently this proposed scheme does not need additional sensors and computers for monitoring the condition of the wind gearbox. The scheme is evaluated on a wide-spread wind...

  20. Economic benefits of metrology in manufacturing

    DEFF Research Database (Denmark)

    Savio, Enrico; De Chiffre, Leonardo; Carmignato, S.

    2016-01-01

    In streamlined manufacturing systems, the added value of inspection activities is often questioned, and metrology in particular is sometimes considered only as an avoidable expense. Documented quantification of economic benefits of metrology is generally not available. This work presents concrete...... examples from industrial production, in which the added value of metrology in manufacturing is discussed and quantified. Case studies include: general manufacturing, forging, machining, and related metrology. The focus of the paper is on the improved effectiveness of metrology when used at product...... and process design stages, as well as on the improved accuracy and efficiency of manufacturing through better measuring equipment and process chains with integrated metrology for process control....

  1. Introduction to quantum metrology quantum standards and instrumentation

    CERN Document Server

    Nawrocki, Waldemar

    2015-01-01

    This book presents the theory of quantum effects used in metrology and results of the author’s own research in the field of quantum electronics. The book provides also quantum measurement standards used in many branches of metrology for electrical quantities, mass, length, time and frequency. This book represents the first comprehensive survey of quantum metrology problems. As a scientific survey, it propagates a new approach to metrology with more emphasis on its connection with physics. This is of importance for the constantly developing technologies and nanotechnologies in particular. Providing a presentation of practical applications of the effects used in quantum metrology for the construction of quantum standards and sensitive electronic components, the book is useful for a wide audience of physicists and metrologists in the broad sense of both terms. In 2014 a new system of units, the so called  Quantum SI, is introduced. This book helps to understand and approve the new system to both technology a...

  2. Metrological multispherical freeform artifact

    Science.gov (United States)

    Blobel, Gernot; Wiegmann, Axel; Siepmann, Jens; Schulz, Michael

    2016-07-01

    Precisely known artifacts are required to characterize the accuracy of asphere and freeform measuring instruments. To this end the best knowledge of the surface characteristics in conjunction with a low measurement uncertainty are necessary. Because this is a challenging task for typical freeform surfaces used in optical systems, the concept of "metrological" artifacts is introduced. We have developed a multispherical freeform artifact for performance tests of tactile touch probe and contact-free optical measuring systems. The measurement accuracy of the complete form and the deviation from calibrated spherical sections can thus be determined. The radius calibration of multiple spherical sections is performed with an extended radius measuring procedure by interferometry. Evaluated surface forms of different measuring methods and the radii determined can be compared to each other. In this study, a multispherical freeform specimen made of copper, with two differing radii, has been measured by two optical measuring methods, a full field measuring tilted-wave interferometer and a high accuracy cylinder coordinate measuring machine with an optical probe. The surface form measurements are evaluated and compared, and the radii determined are compared to the results of a radius measurement bench.

  3. Photonic Quantum Metrologies Using Photons: Phase Super-sensitivity and Entanglement-Enhanced Imaging

    Science.gov (United States)

    Takeuchi, Shigeki

    Quantum information science has been attracting significant attention recently. It harnesses the intrinsic nature of quantum mechanics such as quantum superposition, the uncertainty principle, and quantum entanglement to realize novel functions. Recently, quantum metrology has been emerging as an application of quantum information science. Among the many physical quanta, photons are an indispensable tool for metrology, as light-based measurements are applicable to fields ranging from astronomy to life science. In quantum metrology, quantum entanglement between photons is the phenomenon utilized.In this chapter, we will try to give a brief overview of this emerging field mainly focusing on two topics: Optical phase measurements beyond the standard quantum limit (SQL) and quantum optical coherence tomography (QOCT). The sensitivity of an optical phase measurement for a given photon number N is usually limited by N sqrt{N} , which is called the SQL or shot noise limit. However, the SQL can be overcome when non-classical light is used. We explain the basic concepts and the recent experimental results that exceed the SQL, and an application of this technology for microscopy. QOCT harnesses the quantum entanglement of photons in frequency to cancel out the dispersion effect, which degrades the resolution of conventional OCT. The mechanism of the dispersion cancellation and the latest experimental results will be given.

  4. Using RF Smart Points for the Improvement of Metrological Activities

    Directory of Open Access Journals (Sweden)

    Claudio de Capua

    2007-03-01

    Full Text Available This work describes the realization of a “radio-frequency identification system” for the improvement of the activities of a metrological laboratory. Some radio-frequency modules, called by the authors RF Smart Points (“radio-frequency smart points”, have been designed to store into their memories all data which are necessary for the instruments tracking (the type of instruments, their identification numbers or serial numbers, the manufacturer, the date when they have been admitted to the installed base of the laboratory, their working state, the elapsed time from the last calibration procedure. The insertion of the data and the inquiry of the instruments are executed by the technical staff of the laboratory through a PDA (Personal Digital Assistant or a PC, which manage the radio-frequency communication by using the RS 232 interface for sending messages to a RF Transceiver. The executable software for managing the communication between the Smart Points and the “PDA/PC-Controllers” is realized in LabVIEW graphical programming environment.

  5. A low cost scheme for high precision dual-wavelength laser metrology

    CERN Document Server

    Kok, Yitping; Robertson, J Gordon; Tuthill, Peter G; Warrington, Benjamin A; Tango, William J

    2013-01-01

    A novel method capable of delivering relative optical path length metrology with nanometer precision is demonstrated. Unlike conventional dual-wavelength metrology which employs heterodyne detection, the method developed in this work utilizes direct detection of interference fringes of two He-Ne lasers as well as a less precise stepper motor open-loop position control system to perform its measurement. Although the method may be applicable to a variety of circumstances, the specific application where this metrology is essential is in an astrometric optical long baseline stellar interferometer dedicated to precise measurement of stellar positions. In our example application of this metrology to a narrow-angle astrometric interferometer, measurement of nanometer precision could be achieved without frequency-stabilized lasers although the use of such lasers would extend the range of optical path length the metrology can accurately measure. Implementation of the method requires very little additional optics or el...

  6. PILOT-BASED FREQUENCY OFFSET DETECTION SCHEME IN OFDM SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Du Zheng; Zhu Jinkang

    2003-01-01

    The frequency offset information is extracted from local pilot amplitude characteristics, which suffer much less distortion in frequency-selective fading channels than those utilizing frequency domain correlation techniques. Simulation shows that the performance of this scheme has better performance than the existing frequency domain pilot-based frequency offset detection scheme.

  7. Integration of mask and silicon metrology in DFM

    Science.gov (United States)

    Matsuoka, Ryoichi; Mito, Hiroaki; Sugiyama, Akiyuki; Toyoda, Yasutaka

    2009-03-01

    We have developed a highly integrated method of mask and silicon metrology. The method adopts a metrology management system based on DBM (Design Based Metrology). This is the high accurate contouring created by an edge detection algorithm used in mask CD-SEM and silicon CD-SEM. We have inspected the high accuracy, stability and reproducibility in the experiments of integration. The accuracy is comparable with that of the mask and silicon CD-SEM metrology. In this report, we introduce the experimental results and the application. As shrinkage of design rule for semiconductor device advances, OPC (Optical Proximity Correction) goes aggressively dense in RET (Resolution Enhancement Technology). However, from the view point of DFM (Design for Manufacturability), the cost of data process for advanced MDP (Mask Data Preparation) and mask producing is a problem. Such trade-off between RET and mask producing is a big issue in semiconductor market especially in mask business. Seeing silicon device production process, information sharing is not completely organized between design section and production section. Design data created with OPC and MDP should be linked to process control on production. But design data and process control data are optimized independently. Thus, we provided a solution of DFM: advanced integration of mask metrology and silicon metrology. The system we propose here is composed of followings. 1) Design based recipe creation: Specify patterns on the design data for metrology. This step is fully automated since they are interfaced with hot spot coordinate information detected by various verification methods. 2) Design based image acquisition: Acquire the images of mask and silicon automatically by a recipe based on the pattern design of CD-SEM.It is a robust automated step because a wide range of design data is used for the image acquisition. 3) Contour profiling and GDS data generation: An image profiling process is applied to the acquired image based

  8. Advanced Mathematical Tools in Metrology III

    Science.gov (United States)

    Ciarlini, P.

    Superconducting Magnetic Levitation in Matlab Environment * Data Flow Evaluation in Metrology * A Generalized Data Model for Integrating Clinical Data and Biosignal Records of Patients * Assessment of Three-Dimensional Structures in Clinical Dentistry * Maximum Entropy and Bayesian Approaches to Parameter Estimation in Mass Metrology * Amplitude and Phase Determination of Sinusoidal Vibration in the Nanometer Range using Quadrature Signals * A Class of Symmetric Compactly Supported Wavelets and Associated Dual Bases * Analysis of Surface Topography by Maximum Entropy Power Spectrum Estimation * Influence of Different Kinds of Errors on Imaging Results in Optical Tomography * Application of the Laser Interferometry for Automatic Calibration of Height Setting Micrometer * Author Index

  9. Dimensional micro and nano metrology

    DEFF Research Database (Denmark)

    Hansen, Hans Nørgaard; da Costa Carneiro, Kim; Haitjema, Han

    2006-01-01

    The need for dimensional micro and nano metrology is evident, and as critical dimensions are scaled down and geometrical complexity of objects is increased, the available technologies appear not sufficient. Major research and development efforts have to be undertaken in order to answer these chal......The need for dimensional micro and nano metrology is evident, and as critical dimensions are scaled down and geometrical complexity of objects is increased, the available technologies appear not sufficient. Major research and development efforts have to be undertaken in order to answer...... these challenges. The developments have to include new measuring principles and instrumentation, tolerancing rules and procedures as well as traceability and calibration. The current paper describes issues and challenges in dimensional micro and nano metrology by reviewing typical measurement tasks and available...

  10. Metrology - Beyond the Calibration Lab

    Science.gov (United States)

    Mimbs, Scott M.

    2008-01-01

    We rely on data from measurements every day; a gas-pump, a speedometer, and a supermarket weight scale are just three examples of measurements we use to make decisions. We generally accept the data from these measurements as "valid." One reason we can accept the data is the "legal metrology" requirements established and regulated by the government in matters of commerce. The measurement data used by NASA, other government agencies, and industry can be critical to decisions which affect everything from economic viability, to mission success, to the security of the nation. Measurement data can even affect life and death decisions. Metrology requirements must adequately provide for risks associated with these decisions. To do this, metrology must be integrated into all aspects of an industry including research, design, testing, and product acceptance. Metrology, the science of measurement, has traditionally focused on the calibration of instruments, and although instrument calibration is vital, it is only a part of the process that assures quality in measurement data. For example, measurements made in research can influence the fundamental premises that establish the design parameters, which then flow down to the manufacturing processes, and eventually impact the final product. Because a breakdown can occur anywhere within this cycle, measurement quality assurance has to be integrated into every part of the life-cycle process starting with the basic research and ending with the final product inspection process. The purpose of this paper is to discuss the role of metrology in the various phases of a product's life-cycle. For simplicity, the cycle will be divided in four broad phases, with discussions centering on metrology within NASA. .

  11. Relativistic Quantum Metrology: Exploiting relativity to improve quantum measurement technologies

    CERN Document Server

    Ahmadi, Mehdi; Friis, Nicolai; Sabín, Carlos; Adesso, Gerardo; Fuentes, Ivette

    2013-01-01

    We present a framework for relativistic quantum metrology that is useful for both Earth-based and space-based technologies. Quantum metrology has been so far successfully applied to design precision instruments such as clocks and sensors which outperform classical devices by exploiting quantum properties. There are advanced plans to implement these and other quantum technologies in space, for instance Space-QUEST and Space Optical Clock projects intend to implement quantum communications and quantum clocks at regimes where relativity starts to kick in. However, typical setups do not take into account the effects of relativity on quantum properties. To include and exploit these effects, we introduce techniques for the application of metrology to quantum field theory (QFT). QFT properly incorporates quantum theory and relativity, in particular, at regimes where space-based experiments take place. This framework allows for high precision estimation of parameters that appear in QFT including proper times and acce...

  12. Metrological Reliability of Medical Devices

    Science.gov (United States)

    Costa Monteiro, E.; Leon, L. F.

    2015-02-01

    The prominent development of health technologies of the 20th century triggered demands for metrological reliability of physiological measurements comprising physical, chemical and biological quantities, essential to ensure accurate and comparable results of clinical measurements. In the present work, aspects concerning metrological reliability in premarket and postmarket assessments of medical devices are discussed, pointing out challenges to be overcome. In addition, considering the social relevance of the biomeasurements results, Biometrological Principles to be pursued by research and innovation aimed at biomedical applications are proposed, along with the analysis of their contributions to guarantee the innovative health technologies compliance with the main ethical pillars of Bioethics.

  13. Celtiberian metrology and its romanization

    Directory of Open Access Journals (Sweden)

    Leonard A. CURCHIN

    2013-05-01

    Full Text Available Celtiberian metrology has scarcely been investigated until now, with the exception of coin weights. On the basis of measurements of pre-Roman mud bricks, a Celtiberian foot of 24 cm is proposed. With regard to weights, we can accept a module of 9 g for silver jewelry and some bronze coins; however, loom weights do not conform to any metrological system. Over time, Roman measures of length (as indicated by the dimensions of bricks, tiles and architectural monuments and weight were adopted.

  14. The Limits of CD Metrology

    Science.gov (United States)

    Rice, Bryan J.; Cao, Heidi; Grumski, Michael; Roberts, Jeanette

    2005-09-01

    One of the many technology decisions facing the semiconductor industry for the 32 nm node (and beyond) is the selection of the best critical dimension (CD) metrology equipment to meet the needs of process equipment suppliers and semiconductor manufacturers. Over the past three years Intel ® has fabricated a variety of test structures and performed a number of technology evaluations aimed at determining the limits of today's CD metrology. In this paper we discuss the capability of those technologies to measure structures having dimensions representative of the 45 nm, 32 nm, and 22 nm nodes.

  15. Network-Based and Binless Frequency Analyses.

    Directory of Open Access Journals (Sweden)

    Sybil Derrible

    Full Text Available We introduce and develop a new network-based and binless methodology to perform frequency analyses and produce histograms. In contrast with traditional frequency analysis techniques that use fixed intervals to bin values, we place a range ±ζ around each individual value in a data set and count the number of values within that range, which allows us to compare every single value of a data set with one another. In essence, the methodology is identical to the construction of a network, where two values are connected if they lie within a given a range (±ζ. The value with the highest degree (i.e., most connections is therefore assimilated to the mode of the distribution. To select an optimal range, we look at the stability of the proportion of nodes in the largest cluster. The methodology is validated by sampling 12 typical distributions, and it is applied to a number of real-world data sets with both spatial and temporal components. The methodology can be applied to any data set and provides a robust means to uncover meaningful patterns and trends. A free python script and a tutorial are also made available to facilitate the application of the method.

  16. Metrology Camera System Using Two-Color Interferometry

    Science.gov (United States)

    Dubovitsky, Serge; Liebe, Carl Christian; Peters, Robert; Lay, Oliver

    2007-01-01

    A metrology system that contains no moving parts simultaneously measures the bearings and ranges of multiple reflective targets in its vicinity, enabling determination of the three-dimensional (3D) positions of the targets with submillimeter accuracy. The system combines a direction-measuring metrology camera and an interferometric range-finding subsystem. Because the system is based partly on a prior instrument denoted the Modulation Sideband Technology for Absolute Ranging (MSTAR) sensor and because of its 3D capability, the system is denoted the MSTAR3D. Developed for use in measuring the shape (for the purpose of compensating for distortion) of large structures like radar antennas, it can also be used to measure positions of multiple targets in the course of conventional terrestrial surveying. A diagram of the system is shown in the figure. One of the targets is a reference target having a known, constant distance with respect to the system. The system comprises a laser for generating local and target beams at a carrier frequency; a frequency shifting unit to introduce a frequency shift offset between the target and local beams; a pair of high-speed modulators that apply modulation to the carrier frequency in the local and target beams to produce a series of modulation sidebands, the highspeed modulators having modulation frequencies of FL and FM; a target beam launcher that illuminates the targets with the target beam; optics and a multipixel photodetector; a local beam launcher that launches the local beam towards the multi-pixel photodetector; a mirror for projecting to the optics a portion of the target beam reflected from the targets, the optics being configured to focus the portion of the target beam at the multi-pixel photodetector; and a signal-processing unit connected to the photodetector. The portion of the target beam reflected from the targets produces spots on the multi-pixel photodetector corresponding to the targets, respectively, and the signal

  17. Optical Fibre Based Frequency Shifters Project

    Science.gov (United States)

    1991-01-28

    A fibre optic frequency shifter can be used to replace the Bragg cell acousto-optic modulator, currently used to generate low frequency optical...carriers, in fibre optic communications and sensor systems. This new form of frequency shifter, being an all fibre device, in which the propagating optical...large number of workers in recent years, (for example references [2-81 and those contained therein). The main elements of a fibre - optic frequency

  18. Dimensional quality control of Ti-Ni dental file by optical coordinate metrology and computed tomography

    DEFF Research Database (Denmark)

    Yagüe-Fabra, J.A.; Tosello, Guido; Ontiveros, S.

    2014-01-01

    Endodontic dental files usually present complex 3D geometries, which make the complete measurement of the component very challenging with conventional micro metrology tools. Computed Tomography (CT) can represent a suitable alternative solution to micro metrology tools based on optical and tactil...

  19. Reduction of wafer-edge overlay errors using advanced correction models, optimized for minimal metrology requirements

    Science.gov (United States)

    Kim, Min-Suk; Won, Hwa-Yeon; Jeong, Jong-Mun; Böcker, Paul; Vergaij-Huizer, Lydia; Kupers, Michiel; Jovanović, Milenko; Sochal, Inez; Ryan, Kevin; Sun, Kyu-Tae; Lim, Young-Wan; Byun, Jin-Moo; Kim, Gwang-Gon; Suh, Jung-Joon

    2016-03-01

    In order to optimize yield in DRAM semiconductor manufacturing for 2x nodes and beyond, the (processing induced) overlay fingerprint towards the edge of the wafer needs to be reduced. Traditionally, this is achieved by acquiring denser overlay metrology at the edge of the wafer, to feed field-by-field corrections. Although field-by-field corrections can be effective in reducing localized overlay errors, the requirement for dense metrology to determine the corrections can become a limiting factor due to a significant increase of metrology time and cost. In this study, a more cost-effective solution has been found in extending the regular correction model with an edge-specific component. This new overlay correction model can be driven by an optimized, sparser sampling especially at the wafer edge area, and also allows for a reduction of noise propagation. Lithography correction potential has been maximized, with significantly less metrology needs. Evaluations have been performed, demonstrating the benefit of edge models in terms of on-product overlay performance, as well as cell based overlay performance based on metrology-to-cell matching improvements. Performance can be increased compared to POR modeling and sampling, which can contribute to (overlay based) yield improvement. Based on advanced modeling including edge components, metrology requirements have been optimized, enabling integrated metrology which drives down overall metrology fab footprint and lithography cycle time.

  20. Radio Frequency Based Water Level Monitor and Controller for ...

    African Journals Online (AJOL)

    Radio Frequency Based Water Level Monitor and Controller for Residential Applications. ... Nigerian Journal of Technology ... This paper elucidates a radio frequency (RF) based transmission and reception system used to remotely monitor ...

  1. Why should we apply more metrological knowledge to field measurements?

    Science.gov (United States)

    Buchholz, B.; Kraemer, M.; Rolf, C.; Wagner, S.; Zondlo, M. A.; Ebert, V.

    2016-12-01

    Metrology, the science of measurement, defines the SI, the international system of measurement units, their realization and aims to provide a traceable linkage of measurements to the SI. Primary standards at the national metrology institutes (NMIs) provide the highest achievable accuracy levels linked to the SI and thus are ideal scale reference points to establish long-term comparability between instruments in large networks e.g. in global atmospheric monitoring. However, NMIs offer much more than traceable standards. Metrological communities share internally a large valuable knowledge about "how to measure", e.g. how to calculate, assess and estimate impacts which deteriorate measurements or how to minimize negative impacts and address them in a systematic way with a scientific approach. Over the last years WMO, the world meteorological organization, as well as sub communities in the environmental sciences (e.g. the TCCON or GRUAN network), have greatly increased their efforts to integrate metrological principles and improved the comparability across the network. Prominent examples are airborne water vapor measurements, which, despite the well validated global metrological water scale for industry applications, are only very rarely linked to it, mainly due to the lack of established transfer standards. During the last years our group at PTB developed a new class of optical hygrometers and related validation strategies, in order to reduce deviations of up to 20% found in AquaVIT, a large scale, lab based comparison of leading airborne field hygrometers (Fahey et al, AMT, 7, 3159-3251, 2014) down to a long-term stability over 18 month of 0.35%, making this instrument (SEALDH-II) the first dTDLAS-based airborne transfer standards for atmospheric humidity. These and other examples lead to the conclusion that scientific communities starting to enroll metrological principles significantly improve their measurements and eventually the validity as well as interpretation

  2. Low Noise Frequency Comb Sources Based on Synchronously Pumped Doubly Resonant Optical Parametric Oscillators

    Science.gov (United States)

    Wan, Chenchen

    Optical frequency combs are coherent light sources consist of thousands of equally spaced frequency lines. Frequency combs have achieved success in applications of metrology, spectroscopy and precise pulse manipulation and control. The most common way to generate frequency combs is based on mode-locked lasers which has the output spectrum of comb structures. To generate stable frequency combs, the output from mode-locked lasers need to be phase stabilized. The whole comb lines will be stabilized if the pulse train repetition rate corresponding to comb spacing and the pulse carrier envelope offset (CEO) frequency are both stabilized. The output from a laser always has fluctuations in parameters known as noise. In laser applications, noise is an important factor to limit the performance and often need to be well controlled. For example in precision measurement such as frequency metrology and precise spectroscopy, low laser intensity and phase noise is required. In mode-locked lasers there are different types of noise like intensity noise, pulse temporal position noise also known as timing jitter, optical phase noise. In term for frequency combs, these noise dynamics is more complex and often related. Understanding the noise behavior is not only of great interest in practical applications but also help understand fundamental laser physics. In this dissertation, the noise of frequency combs and mode-locked lasers will be studied in two projects. First, the CEO frequency phase noise of a synchronously pumped doubly resonant optical parametric oscillators (OPO) will be explored. This is very important for applications of the OPO as a coherent frequency comb source. Another project will focus on the intensity noise coupling in a soliton fiber oscillator, the finding of different noise coupling in soliton pulses and the dispersive waves generated from soliton perturbation can provide very practical guidance for low noise soliton laser design. OPOs are used to generate

  3. Topological metrology and its application to optical position sensing

    CERN Document Server

    Tischler, Nora; Singh, Sukhwinder; Zambrana-Puyalto, Xavier; Vidal, Xavier; Brennen, Gavin; Molina-Terriza, Gabriel

    2015-01-01

    We motivate metrology schemes based on topological singularities as a way to build robustness against deformations of the system. In particular, we relate reference settings of metrological systems to topological singularities in the measurement outputs. As examples we discuss optical nano-position sensing (i) using a balanced photodetector and a quadrant photodetector, and (ii) a more general image based scheme. In both cases the reference setting is a scatterer position that corresponds to a topological singularity in an output space constructed from the scattered field intensity distributions.

  4. Differential evolution for many-particle adaptive quantum metrology.

    Science.gov (United States)

    Lovett, Neil B; Crosnier, Cécile; Perarnau-Llobet, Martí; Sanders, Barry C

    2013-05-31

    We devise powerful algorithms based on differential evolution for adaptive many-particle quantum metrology. Our new approach delivers adaptive quantum metrology policies for feedback control that are orders-of-magnitude more efficient and surpass the few-dozen-particle limitation arising in methods based on particle-swarm optimization. We apply our method to the binary-decision-tree model for quantum-enhanced phase estimation as well as to a new problem: a decision tree for adaptive estimation of the unknown bias of a quantum coin in a quantum walk and show how this latter case can be realized experimentally.

  5. [The EFS metrology: From the production to the reason].

    Science.gov (United States)

    Reifenberg, J-M; Riout, E; Leroy, A; Begue, S

    2014-06-01

    In order to answer statutory requirements and to anticipate the future needs and standards, the EFS is committed, since a few years, in a process of harmonization of its metrology function. In particular, the institution has opted for the skills development by internalizing the metrological traceability of the main critical quantities (temperature, volumetric) measurements. The development of metrology so resulted in a significant increase in calibration and testing activities. Methods are homogenized and improved through accreditations. The investment strategies are based on more and more demanding specifications. The performance of the equipments is better known and mastered. Technical expertise and maturity of the national metrology function today are assets to review in more informed ways the appropriateness of the applied periodicities. Analysis of numerous information and data in the calibration and testing reports could be pooled and operated on behalf of the unique establishment. The objective of this article is to illustrate these reflections with a few examples from of a feedback of the EFS Pyrénées Méditerranée. The analysis of some methods of qualification, the exploitation of the historical metrology in order to quantify the risk of non-compliance, and to adapt the control strategy, analysis of the criticality of an instrument in a measurement process, risk analyses are tools that deserve to be more widely exploited for that discipline wins in efficiency at the national level.

  6. The Development of a Deflectometer for Accurate Surface Figure Metrology

    Science.gov (United States)

    Gubarev, Mikhail; Eberhardt, Andrew; Ramsey, Brian; Atkins, Carolyn

    2015-01-01

    Marshall Space Flight Center is developing the method of direct fabrication for high resolution full-shell x-ray optics. In this technique the x-ray optics axial profiles are figured and polished using a computer-controlled ZeekoIRP600X polishing machine. Based on the Chandra optics fabrication history about one third of the manufacturing time is spent on moving a mirror between fabrication and metrology sites, reinstallation and alignment with either the metrology or fabrication instruments. Also, the accuracy of the alignment significantly affects the ultimate accuracy of the resulting mirrors. In order to achieve higher convergence rate it is highly desirable to have a metrology technique capable of in situ surface figure measurements of the optics under fabrication, so the overall fabrication costs would be greatly reduced while removing the surface errors due to the re-alignment necessary after each metrology cycle during the fabrication. The goal of this feasibility study is to demonstrate if the Phase Measuring Deflectometry can be applied for in situ metrology of full shell x-ray optics. Examples of the full-shell mirror substrates suitable for the direct fabrication

  7. Forensic Metrology: Its Importance and Evolution in the United States

    Science.gov (United States)

    Vosk, JD Ted

    2016-11-01

    Forensic measurements play a significant role in the U.S. criminal justice system. Guilt or innocence, or the severity of a sentence, may depend upon the results of such measurements. Until recently, however, forensic disciplines were largely unaware of the field of metrology. Accordingly, proper measurement practices were often, and widely, neglected. These include failure to adopt proper calibration techniques, establish the traceability of results and determine measurement uncertainty. These failures undermine confidence in verdicts based upon forensic measurements. Over the past decade, though, the forensic sciences have been introduced to metrology and its principles leading to more reliable measurement practices. The impetus for this change was driven by many forces. Pressure came initially from criminal defense lawyers challenging metrologically unsound practices and results relied upon by government prosecutions. Litigation in the State of Washington led this movement spurring action by attorneys in other jurisdictions and eventually reform in the measurement practices of forensic labs around the country. Since then, the greater scientific community, other forensic scientists and even prosecutors have joined the fight. This paper describes the fight to improve the quality of justice by the application of metrological principles and the evolution of the field of forensic metrology.

  8. Mode-resolved frequency comb interferometry for high-accuracy long distance measurement

    NARCIS (Netherlands)

    Van den Berg, S.A.; Van Eldik, S.; Bhattacharya, N.

    2015-01-01

    Optical frequency combs have developed into powerful tools for distance metrology. In this paper we demonstrate absolute long distance measurement using a single femtosecond frequency comb laser as a multi-wavelength source. By applying a high-resolution spectrometer based on a virtually imaged phas

  9. Quantum Computing, Metrology, and Imaging

    CERN Document Server

    Lee, H; Dowling, J P; Lee, Hwang; Lougovski, Pavel; Dowling, Jonathan P.

    2005-01-01

    Information science is entering into a new era in which certain subtleties of quantum mechanics enables large enhancements in computational efficiency and communication security. Naturally, precise control of quantum systems required for the implementation of quantum information processing protocols implies potential breakthoughs in other sciences and technologies. We discuss recent developments in quantum control in optical systems and their applications in metrology and imaging.

  10. On Frequency Combs in Monolithic Resonators

    Directory of Open Access Journals (Sweden)

    Savchenkov A. A.

    2016-06-01

    Full Text Available Optical frequency combs have become indispensable in astronomical measurements, biological fingerprinting, optical metrology, and radio frequency photonic signal generation. Recently demonstrated microring resonator-based Kerr frequency combs point the way towards chip scale optical frequency comb generator retaining major properties of the lab scale devices. This technique is promising for integrated miniature radiofrequency and microwave sources, atomic clocks, optical references and femtosecond pulse generators. Here we present Kerr frequency comb development in a historical perspective emphasizing its similarities and differences with other physical phenomena. We elucidate fundamental principles and describe practical implementations of Kerr comb oscillators, highlighting associated solved and unsolved problems.

  11. On Frequency Combs in Monolithic Resonators

    Science.gov (United States)

    Savchenkov, A. A.; Matsko, A. B.; Maleki, L.

    2016-06-01

    Optical frequency combs have become indispensable in astronomical measurements, biological fingerprinting, optical metrology, and radio frequency photonic signal generation. Recently demonstrated microring resonator-based Kerr frequency combs point the way towards chip scale optical frequency comb generator retaining major properties of the lab scale devices. This technique is promising for integrated miniature radiofrequency and microwave sources, atomic clocks, optical references and femtosecond pulse generators. Here we present Kerr frequency comb development in a historical perspective emphasizing its similarities and differences with other physical phenomena. We elucidate fundamental principles and describe practical implementations of Kerr comb oscillators, highlighting associated solved and unsolved problems.

  12. Thermal-Diffusivity-Based Frequency References in Standard CMOS

    NARCIS (Netherlands)

    Kashmiri, S.M.

    2012-01-01

    In recent years, a lot of research has been devoted to the realization of accurate integrated frequency references. A thermal-diffusivity-based (TD) frequency reference provides an alternative method of on-chip frequency generation in standard CMOS technology. A frequency-locked loop locks the

  13. Thermal-Diffusivity-Based Frequency References in Standard CMOS

    NARCIS (Netherlands)

    Kashmiri, S.M.

    2012-01-01

    In recent years, a lot of research has been devoted to the realization of accurate integrated frequency references. A thermal-diffusivity-based (TD) frequency reference provides an alternative method of on-chip frequency generation in standard CMOS technology. A frequency-locked loop locks the outpu

  14. Instantaneous frequency based newborn EEG seizure characterisation

    Science.gov (United States)

    Mesbah, Mostefa; O'Toole, John M.; Colditz, Paul B.; Boashash, Boualem

    2012-12-01

    The electroencephalogram (EEG), used to noninvasively monitor brain activity, remains the most reliable tool in the diagnosis of neonatal seizures. Due to their nonstationary and multi-component nature, newborn EEG seizures are better represented in the joint time-frequency domain than in either the time domain or the frequency domain. Characterising newborn EEG seizure nonstationarities helps to better understand their time-varying nature and, therefore, allow developing efficient signal processing methods for both modelling and seizure detection and classification. In this article, we used the instantaneous frequency (IF) extracted from a time-frequency distribution to characterise newborn EEG seizures. We fitted four frequency modulated (FM) models to the extracted IFs, namely a linear FM, a piecewise-linear FM, a sinusoidal FM, and a hyperbolic FM. Using a database of 30-s EEG seizure epochs acquired from 35 newborns, we were able to show that, depending on EEG channel, the sinusoidal and piecewise-linear FM models best fitted 80-98% of seizure epochs. To further characterise the EEG seizures, we calculated the mean frequency and frequency span of the extracted IFs. We showed that in the majority of the cases (>95%), the mean frequency resides in the 0.6-3 Hz band with a frequency span of 0.2-1 Hz. In terms of the frequency of occurrence of the four seizure models, the statistical analysis showed that there is no significant difference( p = 0.332) between the two hemispheres. The results also indicate that there is no significant differences between the two hemispheres in terms of the mean frequency ( p = 0.186) and the frequency span ( p = 0.302).

  15. Widely-tunable mid-infrared frequency comb source based on difference frequency generation

    NARCIS (Netherlands)

    Ruehl, A.; Gambetta, A.; Hartl, I.; Fermann, M.E.; Eikema, K.S.E.; Marangoni, M.

    2012-01-01

    We report on a mid-IR frequency comb source of unprecedented tunability covering the entire 3-10 mu m molecular fingerprint region. The system is based on difference frequency generation in a GaSe crystal pumped by a 151 MHz Yb:fiber frequency comb. The process was seeded with Raman-shifted solitons

  16. A compact high-sensitivity heterodyne interferometer for industrial metrology

    Science.gov (United States)

    Schuldt, Thilo; Gohlke, Martin; Weise, Dennis; Peters, Achim; Johann, Ulrich; Braxmaier, Claus

    2008-04-01

    For translation and tilt metrology, we developed a compact fiber-coupled polarizing heterodyne interferometer which is based on a highly symmetric design where both, measurement and reference beam have similar optical pathlengths and the same frequency and polarization. The method of differential wavefront sensing is implemented for tilt measurement. With this setup we reached noise levels below 5 pm/square root of Hz; Hz in translation and below 10 nrad/square root of Hz; in tilt measurement, both for frequencies above 10-2 Hz. While this setup is developed with respect to the requirements of the LISA (Laser Interferometer Space Antenna) space mission, we here present the current status of its adoption to industrial applications. We currently design a very compact and quasi-monolithic setup of the interferometer sensor head based on ultra-low expansion glass material. The resulting compact and robust sensor head can be used for nano-positioning control. We also plan to implement a scan of the measurement beam over the surface under investigation enabling high resolution 3D profilometry and surface property measurements (i. e. roughness, evenness and roundness). The dedicated low-noise (piezo-electric actuator in the measurement beam of the interferometer will be realized using integrated micro-system technology and can either be implemented in one or two dimensions.

  17. Theory of a metrology for the earths magnetic field based on the resonance of polarised atomic nuclei (1962); Theorie d'une metrologie du champ magnetique terrestre basee sur la resonance de noyaux atomiques polarises (1962)

    Energy Technology Data Exchange (ETDEWEB)

    Bonnet, G. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1961-06-15

    The problems presented by the metrology of the earths field are studied from two points of view. a. The first, purely physical, concerns the study of NMR transducers in their role for the transformation of the magnetic field into a frequency. The possibilities and limitations are outlined. The use of an equivalent model is introduced systematically in the considerations of NMR phenomena, this makes it possible to treat all problems of interaction between a spin system and an electric detection system in a unified form. b. The other point of view concerns the restitution of the nuclear signal frequency in the form of a directly perceptible observable. The treatment of information is considered from a statistical angle, which leads to the study of an optimisation process concerning the linearization of the measurement as well as the minimisation of noise effects. (author) [French] Les problemes que pose la metrologie du champ terrestre sont etudies sous un double aspect: a. L'un, purement physique, concerne l'etude des traducteurs a RMN dans leur role de transformation du champ magnetique en une frequence. On en degage les possibilites et les limitations. L'emploi d'un modele equivalent est introduit de maniere systematique pour rendre compte des phenomenes de RMN, ce qui permet de traiter sous forme unifiee tous les problemes d'interaction entre un systeme de spins et un systeme electrique de detection. b. L'autre aspect concerne la restitution de la frequence du signal nucleaire sous la forme d'une observable directement perceptible. On considere le traitement de l'information sous l'aspect statistique, ce qui amene a etudier un processus d'optimisation concernant la linearisation de la mesure aussi bien que la minimisation des effets des bruits. (auteur)

  18. Slow light based optical frequency shifter

    CERN Document Server

    Li, Qian; Thuresson, Axel; Nilsson, Adam N; Rippe, Lars; Kröll, Stefan

    2016-01-01

    We demonstrate experimentally and theoretically a controllable way of shifting the frequency of an optical pulse by using a combination of spectral hole burning, slow light effect, and linear Stark effect in a rare-earth-ion doped crystal. We claim that the solid angle of acceptance of a frequency shift structure can be close to $2\\pi$, which means that the frequency shifter could work not only for optical pulses propagating in a specific spatial mode but also for randomly scattered light. As the frequency shift is controlled solely by an external electric field, it works also for weak coherent light fields, and can e.g. be used as a frequency shifter for quantum memory devices in quantum communication.

  19. Management of metrology in measuring of the displacement of building construction

    Directory of Open Access Journals (Sweden)

    Jiří Kratochvíl

    2007-06-01

    Full Text Available The metrology management of the measurement of the displacement of building construction is not regulated in the standard ČSN ISO 73 0405 - Measurement of the displacement of building construction. But the metrology management has to be included in the project of measurement of the displacement (Stage of project. Then we have to pay an attention to the metrological management during this measurement (Stage of realization and during the evaluation of this measurement (Stage of evaluation. We have to insist on the subsequent improving of metrology management within the frame of the next project (so-called feedback. The metrology management in the measurement of the displacement during the stages should be based on an application of statutory instruments and technical standards. We should insist especially on the system of standards for the quality control ISO 9000. Considering specialities of geodetic measurements it is necessary to adapt the metrology management. That is why it will differ from the metrology management in other fields of knowledge. This paper includes some steps of metrological provision which must not be ignored.

  20. Fabrication of metrology test structures with helium ion beam direct write

    Science.gov (United States)

    Lee, Chien-Lin; Chien, Sheng-Wei; Chen, Sheng-Yung; Liu, Chun-Hung; Tsai, Kuen-Yu; Li, Jia-Han; Shew, Bor-Yuan; Hong, Chit-Sung; Lee, Chao-Te

    2017-03-01

    The availability of metrology solutions, one of the key factors to drive leading edge semiconductor devices and processes, can be confronted with difficulties in the advanced node. For developing new metrology solutions, high quality test structures fabricated at specific sizes are needed. Conventional resist-based lithography have been utilized to manufacture such samples. However, it can encounter significant resolution difficulties or requiring complicated optimization process for advanced technology node. In this work, potential of helium ion beam direct milling (HIBDM) for fabricating metrology test structures with programmed imperfection is investigated. Features down to 5 nm are resolvable without implementing any optimization method. Preliminary results have demonstrated that HIBDM can be a promising alternative to fabricate metrology test structures for advanced metrology solutions in sub 10 nm node.

  1. Target tracking based on frequency spectrum amplitude

    Institute of Scientific and Technical Information of China (English)

    Guo Huidong; Zhang Xinhua; Xia Zhijun

    2006-01-01

    The amplitude of frequency spectrum can be integrated with probabilistic data association (PDA) to distinguish the target with clutter echoes, especially in low SNR underwater environment. A new target-tracking algorithm is presented which adopts the amplitude of frequency spectrum to improve target tracking in clutter. The probabilistic density distribution of frequency spectrum amplitude is analyzed. By simulation, the results show that the algorithm is superior to PDA. This approach enhances stability for the association probability and increases the performance of target tracking.

  2. Low-cost scheme for high-precision dual-wavelength laser metrology.

    Science.gov (United States)

    Kok, Yitping; Ireland, Michael J; Robertson, J Gordon; Tuthill, Peter G; Warrington, Benjamin A; Tango, William J

    2013-04-20

    A method capable of delivering relative optical path length metrology with nanometer precision is demonstrated. Unlike conventional dual-wavelength metrology, which employs heterodyne detection, the method developed in this work utilizes direct detection of interference fringes of two He-Ne lasers as well as a less precise stepper motor open-loop position control system to perform its measurement. Although the method may be applicable to a variety of circumstances, the specific application in which this metrology is essential is in an astrometric optical long baseline stellar interferometer dedicated to precise measurement of stellar positions. In our example application of this metrology to a narrow-angle astrometric interferometer, measurement of nanometer precision could be achieved without frequency-stabilized lasers, although the use of such lasers would extend the range of optical path length the metrology can accurately measure. Implementation of the method requires very little additional optics or electronics, thus minimizing the cost and effort of implementation. Furthermore, the optical path traversed by the metrology lasers is identical to that of the starlight or science beams, even down to using the same photodetectors, thereby minimizing the noncommon path between metrology and science channels.

  3. METROLOGICAL PERFORMANCE OF SEM 3D TECHNIQUES

    DEFF Research Database (Denmark)

    Marinello, Francesco; Carmignato, Simone; Savio, Enrico;

    2008-01-01

    This paper addresses the metrological performance of three-dimensional measurements performed with Scanning Electron Microscopes (SEMs) using reconstruction of surface topography through stereo-photogrammetry. Reconstruction is based on the model function introduced by Piazzesi adapted for eucent...... condition are studied, in order to define a strategy to optimise the measurements taking account of the critical factors in SEM 3D reconstruction. Investigations were performed on a novel sample, specifically developed and implemented for the tests.......This paper addresses the metrological performance of three-dimensional measurements performed with Scanning Electron Microscopes (SEMs) using reconstruction of surface topography through stereo-photogrammetry. Reconstruction is based on the model function introduced by Piazzesi adapted...... and the instrument set-up; the second concerns the quality of scanned images and represents the major criticality in the application of SEMs for 3D characterizations. In particular the critical role played by the tilting angle and its relative uncertainty, the magnification and the deviations from the eucentricity...

  4. Cryocooled Josephson standards for AC voltage metrology

    Science.gov (United States)

    Durandetto, P.; Sosso, A.; Monticone, E.; Trinchera, B.; Fretto, M.; Lacquaniti, V.

    2017-05-01

    The Josephson effect is worldwide used as a basis for constant reference voltages in national metrological institutes and in calibration laboratories of industry. Research on Josephson voltage standards is aiming at a fundamental change also in the metrology of the volt for AC and arbitrary waveforms: programmable Josephson voltage standards converting a digital code into a quantum-accurate stepwise waveform are already available in primary laboratories and even more advanced standards for converting sub-nanosecond binary coded pulses into any arbitrary signal with quantum accuracy are now actively developed and tested. A new experimental setup based on a two-stage Gifford-McMahon cryocooler has been developed at INRiM for the operation of AC-Josephson voltage standards. Among its distinct features, the possibility of employing both the aforementioned techniques (programmable and pulsed Josephson voltage standards) is particularly interesting. Quantum-based AC voltage sine waves have been synthesized with both programmable and pulse-driven arrays, although their accuracy is still limited by thermal oscillations due to the cryocooler piston motion.

  5. Low velocity target detection based on time-frequency image for high frequency ground wave radar

    Institute of Scientific and Technical Information of China (English)

    YAN Songhua; WU Shicai; WEN Biyang

    2007-01-01

    The Doppler spectral broadening resulted from non-stationary movement of target and radio-frequency interference will decrease the veracity of target detection by high frequency ground wave(HEGW)radar.By displaying the change of signal energy on two dimensional time-frequency images based on time-frequency analysis,a new mathematical morphology method to distinguish target from nonlinear time-frequency curves is presented.The analyzed results from the measured data verify that with this new method the target can be detected correctly from wide Doppler spectrum.

  6. Microresonator-based optical frequency combs.

    Science.gov (United States)

    Kippenberg, T J; Holzwarth, R; Diddams, S A

    2011-04-29

    The series of precisely spaced, sharp spectral lines that form an optical frequency comb is enabling unprecedented measurement capabilities and new applications in a wide range of topics that include precision spectroscopy, atomic clocks, ultracold gases, and molecular fingerprinting. A new optical frequency comb generation principle has emerged that uses parametric frequency conversion in high resonance quality factor (Q) microresonators. This approach provides access to high repetition rates in the range of 10 to 1000 gigahertz through compact, chip-scale integration, permitting an increased number of comb applications, such as in astronomy, microwave photonics, or telecommunications. We review this emerging area and discuss opportunities that it presents for novel technologies as well as for fundamental science.

  7. Quantum metrology in non-Markovian environments.

    Science.gov (United States)

    Chin, Alex W; Huelga, Susana F; Plenio, Martin B

    2012-12-07

    We analyze precision bounds for a local phase estimation in the presence of general, non-Markovian phase noise. We demonstrate that the metrological equivalence of product and maximally entangled states that holds under strictly Markovian dephasing fails in the non-Markovian case. Using an exactly solvable model of a physically realistic finite bandwidth dephasing environment, we demonstrate that the ensuing non-Markovian dynamics enables quantum correlated states to outperform metrological strategies based on uncorrelated states using otherwise identical resources. We show that this conclusion is a direct result of the coherent dynamics of the global state of the system and environment and therefore the obtained scaling with the number of particles, which surpasses the standard quantum limit but does not achieve Heisenberg resolution, possesses general validity that goes beyond specific models. This is in marked contrast with the situation encountered under general Markovian noise, where an arbitrarily small amount of noise is enough to restore the scaling dictated by the standard quantum limit.

  8. Metrology Optical Power Budgeting in SIM Using Statistical Analysis Techniques

    Science.gov (United States)

    Kuan, Gary M

    2008-01-01

    The Space Interferometry Mission (SIM) is a space-based stellar interferometry instrument, consisting of up to three interferometers, which will be capable of micro-arc second resolution. Alignment knowledge of the three interferometer baselines requires a three-dimensional, 14-leg truss with each leg being monitored by an external metrology gauge. In addition, each of the three interferometers requires an internal metrology gauge to monitor the optical path length differences between the two sides. Both external and internal metrology gauges are interferometry based, operating at a wavelength of 1319 nanometers. Each gauge has fiber inputs delivering measurement and local oscillator (LO) power, split into probe-LO and reference-LO beam pairs. These beams experience power loss due to a variety of mechanisms including, but not restricted to, design efficiency, material attenuation, element misalignment, diffraction, and coupling efficiency. Since the attenuation due to these sources may degrade over time, an accounting of the range of expected attenuation is needed so an optical power margin can be book kept. A method of statistical optical power analysis and budgeting, based on a technique developed for deep space RF telecommunications, is described in this paper and provides a numerical confidence level for having sufficient optical power relative to mission metrology performance requirements.

  9. X-ray optical systems: from metrology to Point Spread Function

    CERN Document Server

    Spiga, D

    2015-01-01

    One of the problems often encountered in X-ray mirror manufacturing is setting proper manufacturing tolerances to guarantee an angular resolution - often expressed in terms of Point Spread Function (PSF) - as needed by the specific science goal. To do this, we need an accurate metrological apparatus, covering a very broad range of spatial frequencies, and an affordable method to compute the PSF from the metrology dataset. [...] However, the separation between these spectral ranges is difficult do define exactly, and it is also unclear how to affordably combine the PSFs, computed with different methods in different spectral ranges, into a PSF expectation at a given X-ray energy. For this reason, we have proposed a method entirely based on the Huygens-Fresnel principle to compute the diffracted field of real Wolter-I optics, including measured defects over a wide range of spatial frequencies. Owing to the shallow angles at play, the computation can be simplified limiting the computation to the longitudinal prof...

  10. Nonlinear metrology with a quantum interface

    OpenAIRE

    Napolitano, M.; Mitchell, M. W.

    2009-01-01

    We describe nonlinear quantum atom-light interfaces and nonlinear quantum metrology in the collective continuous variable formalism. We develop a nonlinear effective Hamiltonian in terms of spin and polarization collective variables and show that model Hamiltonians of interest for nonlinear quantum metrology can be produced in $^{87}$Rb ensembles. With these Hamiltonians, metrologically relevant atomic properties, e.g. the collective spin, can be measured better than the "Heisenberg limit" $\\...

  11. Pulse frequency classification based on BP neural network

    Institute of Scientific and Technical Information of China (English)

    WANG Rui; WANG Xu; YANG Dan; FU Rong

    2006-01-01

    In Traditional Chinese Medicine (TCM), it is an important parameter of the clinic disease diagnosis to analysis the pulse frequency. This article accords to pulse eight major essentials to identify pulse type of the pulse frequency classification based on back-propagation neural networks (BPNN). The pulse frequency classification includes slow pulse, moderate pulse, rapid pulse etc. By feature parameter of the pulse frequency analysis research and establish to identify system of pulse frequency features. The pulse signal from detecting system extracts period, frequency etc feature parameter to compare with standard feature value of pulse type. The result shows that identify-rate attains 92.5% above.

  12. Optical-frequency-comb based ultrasound sensor

    Science.gov (United States)

    Minamikawa, Takeo; Ogura, Takashi; Masuoka, Takashi; Hase, Eiji; Nakajima, Yoshiaki; Yamaoka, Yoshihisa; Minoshima, Kaoru; Yasui, Takeshi

    2017-03-01

    Photo-acoustic imaging is a promising modality for deep tissue imaging with high spatial resolution in the field of biology and medicine. High penetration depth and spatial resolution of the photo-acoustic imaging is achieved by means of the advantages of optical and ultrasound imaging, i.e. tightly focused beam confines ultrasound-generated region within micrometer scale and the ultrasound can propagate through tissues without significant energy loss. To enhance the detection sensitivity and penetration depth of the photo-acoustic imaging, highly sensitive ultrasound detector is greatly desired. In this study, we proposed a novel ultrasound detector employing optical frequency comb (OFC) cavity. Ultrasound generated by the excitation of tightly focused laser beam onto a sample was sensed with a part of an OFC cavity, being encoded into OFC. The spectrally encoded OFC was converted to radio-frequency by the frequency link nature of OFC. The ultrasound-encoded radio-frequency can therefore be directly measured with a high-speed photodetector. We constructed an OFC cavity for ultrasound sensing with a ring-cavity erbium-doped fiber laser. We provided a proof-of-principle demonstration of the detection of ultrasound that was generated by a transducer operating at 10 MHz. Our proposed approach will serve as a unique and powerful tool for detecting ultrasounds for photo-acoustic imaging in the future.

  13. TNO TPD contributions to high precision optical metrology, a Darwin metrology breadboard for ESA

    NARCIS (Netherlands)

    Verlaan, A.L.; Dool, T.C. van den; Braam, B.C.; Calvel, B.; Sesselman, R.; Pöschel, W.; Dontsov, D.; Vega, I.C.; Manske, E.; Schuldt, T.; Sodnik, Z.

    2004-01-01

    A Darwin precursor breadboard, comprising both fine lateral and longitudinal metrology sensors was designed, built and partially tested. The lateral metrology sensor was designed and built by TNO TPD and more than meets the imposed requirements. The longitudinal metrology sensor consists of a dual

  14. TNO TPD contributions to high precision optical metrology, a Darwin metrology breadboard for ESA

    NARCIS (Netherlands)

    Verlaan, A.L.; Dool, T.C. van den; Braam, B.C.; Calvel, B.; Sesselman, R.; Pöschel, W.; Dontsov, D.; Vega, I.C.; Manske, E.; Schuldt, T.; Sodnik, Z.

    2004-01-01

    A Darwin precursor breadboard, comprising both fine lateral and longitudinal metrology sensors was designed, built and partially tested. The lateral metrology sensor was designed and built by TNO TPD and more than meets the imposed requirements. The longitudinal metrology sensor consists of a dual w

  15. Frequency feature based quantification of defect depth and thickness

    Science.gov (United States)

    Tian, Shulin; Chen, Kai; Bai, Libing; Cheng, Yuhua; Tian, Lulu; Zhang, Hong

    2014-06-01

    This study develops a frequency feature based pulsed eddy current method. A frequency feature, termed frequency to zero, is proposed for subsurface defects and metal loss quantification in metallic specimens. A curve fitting method is also employed to generate extra frequency components and improve the accuracy of the proposed method. Experimental validation is carried out. Conclusions and further work are derived on the basis of the studies.

  16. The metrology of time.

    Science.gov (United States)

    Arias, Elisa Felicitas

    2005-09-15

    Measuring time is a continuous activity, an international and restless enterprise hidden in time laboratories spread all over the planet. The Bureau International des Poids et Mesures is charged with coordinating activities for international timekeeping and it makes use of the world's capacity to produce a remarkably stable and accurate reference time-scale. Commercial atomic clocks beating the second in national laboratories can reach a stability of one part in 10(14) over a 5 day averaging time, compelling us to research the most highly performing methods of remote clock comparison. The unit of the international time-scale is the second of the International System of Units, realized with an uncertainty of the order 10(-15) by caesium fountains. Physicists in a few time laboratories are making efforts to gain one order of magnitude in the uncertainty of the realization of the second, and more refined techniques of time and frequency transfer are in development to accompany this progress. Femtosecond comb technology will most probably contribute in the near future to enhance the definition of the second with the incorporation of optical clocks. We will explain the evolution of the measuring of time, current state-of-the-art measures and future challenges.

  17. Frequency-Shift of a Frequency Stabilized Laser Based on Zeeman Effect

    Institute of Scientific and Technical Information of China (English)

    魏荣; 邓见辽; 钱勇; 张宇; 王育竹

    2003-01-01

    We introduce a new method of frequency-shifting for a diode laser in laser cooling experiments, the method is based on the Zeeman effect of 87Rb atoms. The laser frequency is stabilized by absorption spectrum line of atoms in magnetic field. We show that a magnetic field can be added up to 10-2T. The corresponding frequency shift is 102MHz and the response time is about 1 ms. The large range of the frequency shift is sufficient for laser-cooling experiments.

  18. Towards the Realization of Graphene Based Flexible Radio Frequency Receiver

    Directory of Open Access Journals (Sweden)

    Maruthi N. Yogeesh

    2015-11-01

    Full Text Available We report on our progress and development of high speed flexible graphene field effect transistors (GFETs with high electron and hole mobilities (~3000 cm2/V·s, and intrinsic transit frequency in the microwave GHz regime. We also describe the design and fabrication of flexible graphene based radio frequency system. This RF communication system consists of graphite patch antenna at 2.4 GHz, graphene based frequency translation block (frequency doubler and AM demodulator and graphene speaker. The communication blocks are utilized to demonstrate graphene based amplitude modulated (AM radio receiver operating at 2.4 GHz.

  19. Dimensional Metrology for Microtechnology

    DEFF Research Database (Denmark)

    Bariani, Paolo

    2005-01-01

    of the (large) CMM positioning errors. A geometrical (three dimensional) model, for the Large range AFM was produced and calibration issues discussed following the three dimensional approach. Furthermore, a novel measuring procedure, based on two images, for eliminating the effects of vertical drift...... of one percent, with this instrument. Uncertainty is dominated by residual non linearity after off line correction. SEM based stereo-photogrammetry was also studied. A commercially available software package was purchased. The working hypothesis for the package in use was eucentric tilting. This is only...

  20. Adaptive Fourier Decomposition Based Time-Frequency Analysis

    Institute of Scientific and Technical Information of China (English)

    Li-Ming Zhang

    2014-01-01

    The attempt to represent a signal simultaneously in time and frequency domains is full of challenges. The recently proposed adaptive Fourier decomposition (AFD) offers a practical approach to solve this problem. This paper presents the principles of the AFD based time-frequency analysis in three aspects: instantaneous frequency analysis, frequency spectrum analysis, and the spectrogram analysis. An experiment is conducted and compared with the Fourier transform in convergence rate and short-time Fourier transform in time-frequency distribution. The proposed approach performs better than both the Fourier transform and short-time Fourier transform.

  1. Non-null full field X-ray mirror metrology using SCOTS: a reflection deflectometry approach.

    Science.gov (United States)

    Su, Peng; Wang, Yuhao; Burge, James H; Kaznatcheev, Konstantine; Idir, Mourad

    2012-05-21

    In a previous paper, the University of Arizona (UA) has developed a measurement technique called: Software Configurable Optical Test System (SCOTS) based on the principle of reflection deflectometry. In this paper, we present results of this very efficient optical metrology method applied to the metrology of X-ray mirrors. We used this technique to measure surface slope errors with precision and accuracy better than 100 nrad (rms) and ~200 nrad (rms), respectively, with a lateral resolution of few mm or less. We present results of the calibration of the metrology systems, discuss their accuracy and address the precision in measuring a spherical mirror.

  2. Frequency metrology in the near-infrared spectrum of H{sub 2}{sup 17}O and H{sub 2}{sup 18}O molecules: testing a new inversion method for retrieval of energy levels

    Energy Technology Data Exchange (ETDEWEB)

    Gambetta, A; Marangoni, M [Campus Point, Dipartimento di Fisica del Politecnico di Milano, Via Ghislanzoni 24, 23900 Lecco (Italy); Fasci, E; Castrillo, A; Casa, G; Gianfrani, L [Dipartimento di Scienze Ambientali della Seconda Universita di Napoli and CNISM-Unita Napoli 2, Via Vivaldi 43, 81100 Caserta (Italy); Galzerano, G; Laporta, P, E-mail: livio.gianfrani@unina2.i [Istituto di Fotonica e Nanotecnologie-CNR and Dipartimento di Fisica del Politecnico di Milano, Piazza Leonardo Da Vinci 32, 20133 Milano (Italy)

    2010-10-15

    An extensive Doppler-free spectroscopic investigation of the near-infrared absorption spectrum of the H{sub 2}{sup 18}O molecule was performed, for the first time, with absolute frequency calibration by using a GPS-disciplined fiber-based optical frequency comb. The investigated line pairs belong to the {nu}{sub 1}+{nu}{sub 3} band and have been chosen in the wavelength range from 1.38 to 1.41{mu}m with a lambda scheme, so as to share the excited energy level and allow an accurate determination of the rotational energy separations of the fundamental vibrational state. The measurement of the sub-Doppler line-center frequencies, also extended to the H{sub 2}{sup 17}O spectrum, has been performed with an overall uncertainty of {approx}30 kHz, i.e. about three orders of magnitude lower than the HITRAN data set. The retrieved energy separations agree, by less than 80 kHz, with recent findings provided by the so-called MARVEL procedure for spectral data inversion, thus yielding a very stringent test of its accuracy.

  3. Monitoring acidic and basic molecular contamination in leading edge lithography and metrology applications: quantitative comparison of solid state and impinger-based sampling methods

    Science.gov (United States)

    Riddle Vogt, Sarah; Landoni, Cristian

    2010-03-01

    Assessing molecular contamination (MC) at part-per-billion (ppbV) or part-per-trillion volume (pptV) levels in cleanroom air and purge gas lines is essential to protect lithography and metrology tools optics and components. Current lithography and metrology tool manufacturer's specifications require testing of some contaminants down to single digit pptV levels. Ideally this analysis would be performed with an on-line analyzer (capable of providing almost instant results): the best analyzers currently available are only capable of providing 100 pptV detection. Liquid impinger sampling has been the dominant sample collection method for sub ppbV acidic and basic MC analysis. Impinger sampling suffers from some inherent problems that can dramatically reduce the collection efficiency such as analyte solubility and evaporative losses. An innovative solid-state trapping technology has been recently developed by SAES Pure Gas along with the CollectTorr sampling system. NIST traceable gas phase standards have been used to compare the collection efficiency of the traditional impinger technology to that of the solid state trapping method. Results varied greatly for the different acid gases with sulfur dioxide showing comparable collection efficiencies while hydrofluoric acid and hydrochloric acid showed much lower recoveries in the impingers than the solid-state traps. Ammonia collection efficiencies were slightly higher for the solid state traps and were improved in the impingers when an acidified solution was used as the collection media. The use of solid-state traps, besides being much simpler from both the handling and logistical stand point, eliminates the analyte solubility and evaporation problems frequently seen with the impinger sampling.

  4. Load balancing in distributed framework for frequency based thread pools

    Directory of Open Access Journals (Sweden)

    Sheraz Ahmad

    2016-12-01

    Full Text Available The consequence of load balancing algorithms on a thread pool framework name is distributed load balancing frequency based optimization scheme (LDFBOS to increase its execution. Load balancing in distributed frequency based thread pool scheme is residential towards the ground of synchronizing overhead crude named LDFBOS in Java that slows down its execution due to framework exchange and synchronizing overhead in nodes, we are demonstrating the contrive and execution of load balancing in distributed frequency based thread pool LDFBOS to does usage from distributed in frequency based thread pool (DFBOS, synchronizing primitives that propose benefits of significant scalable moreover, dynamism. We have got resembled the execution of some schemes by Thread Pool Tester which is a Java application simulator and the consequence have demonstrated that load balancing in distributed frequency based thread pool LDFBOS exceeds preceding DFBOS scheme.

  5. Heisenberg limit superradiant superresolving metrology.

    Science.gov (United States)

    Wang, Da-Wei; Scully, Marlan O

    2014-08-22

    We propose a superradiant metrology technique to achieve the Heisenberg limit superresolving displacement measurement by encoding multiple light momenta into a three-level atomic ensemble. We use 2N coherent pulses to prepare a single excitation superradiant state in a superposition of two timed Dicke states that are 4N light momenta apart in momentum space. The phase difference between these two states induced by a uniform displacement of the atomic ensemble has 1/4N sensitivity. Experiments are proposed in crystals and in ultracold atoms.

  6. Loschmidt echo for quantum metrology

    Science.gov (United States)

    Macrı, Tommaso; Smerzi, Augusto; Pezzè, Luca

    2016-07-01

    We propose a versatile Loschmidt echo protocol to detect and quantify multiparticle entanglement. It allows us to extract the quantum Fisher information for arbitrary pure states, and finds direct application in quantum metrology. In particular, the protocol applies to states that are generally difficult to characterize, as non-Gaussian states, and states that are not symmetric under particle exchange. We focus on atomic systems, including trapped ions, polar molecules, and Rydberg atoms, where entanglement is generated dynamically via long-range interaction, and show that the protocol is stable against experimental detection errors.

  7. Pico meter metrology for the GAIA mission

    NARCIS (Netherlands)

    Meijer, E.A.; Nijenhuis, J.N.; Vink, R.J.P.; Kamphues, F.G.; Gielesen, W.L.M.; Coatantiec, C.

    2009-01-01

    To measure the relative motions of GAIA's telescopes, the angle between the telescopes is monitored by an all Silicon Carbide Basic Angle Monitoring subsystem (BAM OMA). TNO is developing this metrology system. The stability requirements for this metrology system go into the pico meter and pico radi

  8. Metrology Careers: Jobs for Good Measure

    Science.gov (United States)

    Liming, Drew

    2009-01-01

    What kind of career rewards precision and accuracy? One in metrology--the science of measurement. By evaluating and calibrating the technology in people's everyday lives, metrologists keep their world running smoothly. Metrology is used in the design and production of almost everything people encounter daily, from the cell phones in their pockets…

  9. Metrology measurements for large-aperture VPH gratings

    Science.gov (United States)

    Zheng, Jessica R.; Gers, Luke; Heijmans, Jeroen

    2013-09-01

    The High Efficiency and Resolution Multi Element Spectrograph (HERMES) for the Australian Astronomical Observatory (AAO) uses four large aperture, high angle of incidence volume phase holographic gratings (VPHG) for high resolution `Galactic archaeology' spectroscopy. The large clear aperture, the high diffraction efficiency, the line frequency homogeneity, and mosaic alignment made manufacturing and testing challenging. We developed new metrology systems at the AAO to verify the performance of these VPH gratings. The measured diffraction efficiencies and line frequency of the VPH gratings received so far meet the vendor's provided data. The wavefront quality for the Blue VPH grating is good but the Green and Red VPH gratings need to be post polishing.

  10. Ultimate precision of adaptive quantum metrology

    CERN Document Server

    Pirandola, Stefano

    2016-01-01

    We consider the problem of estimating a classical parameter encoded in a quantum channel, assuming the most general strategy allowed by quantum mechanics. This strategy is based on the exploitation of an unlimited amount of pre-shared entanglement plus the use of adaptive probings, where the input of the channel is interactively updated during the protocol. We show that, for the wide class of teleportation-stretchable channels in finite dimension, including all Pauli channels and erasure channels, the quantum Fisher information cannot exceed an ultimate bound given by the Choi matrix of the encoding channel. We also extend our methods and results to quantum channel discrimination, finding a corresponding ultimate bound for the minimum error probability. Thus, our findings establish the ultimate precision limits that are achievable in quantum metrology and quantum discrimination for the most basic models of discrete-variable quantum channels.

  11. Fractal Metrology for biogeosystems analysis

    Directory of Open Access Journals (Sweden)

    V. Torres-Argüelles

    2010-11-01

    Full Text Available The solid-pore distribution pattern plays an important role in soil functioning being related with the main physical, chemical and biological multiscale and multitemporal processes of this complex system. In the present research, we studied the aggregation process as self-organizing and operating near a critical point. The structural pattern is extracted from the digital images of three soils (Chernozem, Solonetz and "Chocolate" Clay and compared in terms of roughness of the gray-intensity distribution quantified by several measurement techniques. Special attention was paid to the uncertainty of each of them measured in terms of standard deviation. Some of the applied methods are known as classical in the fractal context (box-counting, rescaling-range and wavelets analyses, etc. while the others have been recently developed by our Group. The combination of these techniques, coming from Fractal Geometry, Metrology, Informatics, Probability Theory and Statistics is termed in this paper Fractal Metrology (FM. We show the usefulness of FM for complex systems analysis through a case study of the soil's physical and chemical degradation applying the selected toolbox to describe and compare the structural attributes of three porous media with contrasting structure but similar clay mineralogy dominated by montmorillonites.

  12. Fractal Metrology for biogeosystems analysis

    Science.gov (United States)

    Torres-Argüelles, V.; Oleschko, K.; Tarquis, A. M.; Korvin, G.; Gaona, C.; Parrot, J.-F.; Ventura-Ramos, E.

    2010-11-01

    The solid-pore distribution pattern plays an important role in soil functioning being related with the main physical, chemical and biological multiscale and multitemporal processes of this complex system. In the present research, we studied the aggregation process as self-organizing and operating near a critical point. The structural pattern is extracted from the digital images of three soils (Chernozem, Solonetz and "Chocolate" Clay) and compared in terms of roughness of the gray-intensity distribution quantified by several measurement techniques. Special attention was paid to the uncertainty of each of them measured in terms of standard deviation. Some of the applied methods are known as classical in the fractal context (box-counting, rescaling-range and wavelets analyses, etc.) while the others have been recently developed by our Group. The combination of these techniques, coming from Fractal Geometry, Metrology, Informatics, Probability Theory and Statistics is termed in this paper Fractal Metrology (FM). We show the usefulness of FM for complex systems analysis through a case study of the soil's physical and chemical degradation applying the selected toolbox to describe and compare the structural attributes of three porous media with contrasting structure but similar clay mineralogy dominated by montmorillonites.

  13. Fractal metrology for biogeosystems analysis

    Directory of Open Access Journals (Sweden)

    V. Torres-Argüelles

    2010-06-01

    Full Text Available The solid-pore distribution pattern plays an important role in soil functioning being related with the main physical, chemical and biological multiscale and multitemporal processes. In the present research, this pattern is extracted from the digital images of three soils (Chernozem, Solonetz and "Chocolate'' Clay and compared in terms of roughness of the gray-intensity distribution (the measurand quantified by several measurement techniques. Special attention was paid to the uncertainty of each of them and to the measurement function which best fits to the experimental results. Some of the applied techniques are known as classical in the fractal context (box-counting, rescaling-range and wavelets analyses, etc. while the others have been recently developed by our Group. The combination of all these techniques, coming from Fractal Geometry, Metrology, Informatics, Probability Theory and Statistics is termed in this paper Fractal Metrology (FM. We show the usefulness of FM through a case study of soil physical and chemical degradation applying the selected toolbox to describe and compare the main structural attributes of three porous media with contrasting structure but similar clay mineralogy dominated by montmorillonites.

  14. Prestress Force Identification for Externally Prestressed Concrete Beam Based on Frequency Equation and Measured Frequencies

    Directory of Open Access Journals (Sweden)

    Luning Shi

    2014-01-01

    Full Text Available A prestress force identification method for externally prestressed concrete uniform beam based on the frequency equation and the measured frequencies is developed. For the purpose of the prestress force identification accuracy, we first look for the appropriate method to solve the free vibration equation of externally prestressed concrete beam and then combine the measured frequencies with frequency equation to identify the prestress force. To obtain the exact solution of the free vibration equation of multispan externally prestressed concrete beam, an analytical model of externally prestressed concrete beam is set up based on the Bernoulli-Euler beam theory and the function relation between prestress variation and vibration displacement is built. The multispan externally prestressed concrete beam is taken as the multiple single-span beams which must meet the bending moment and rotation angle boundary conditions, the free vibration equation is solved using sublevel simultaneous method and the semi-analytical solution of the free vibration equation which considered the influence of prestress on section rigidity and beam length is obtained. Taking simply supported concrete beam and two-span concrete beam with external tendons as examples, frequency function curves are obtained with the measured frequencies into it and the prestress force can be identified using the abscissa of the crosspoint of frequency functions. Identification value of the prestress force is in good agreement with the test results. The method can accurately identify prestress force of externally prestressed concrete beam and trace the trend of effective prestress force.

  15. Efficient frequency comb generation in AlGaAs-on-insulator

    DEFF Research Database (Denmark)

    Pu, Minhao; Ottaviano, Luisa; Semenova, Elizaveta;

    2016-01-01

    The combination of nonlinear and integrated photonics enables Kerr frequency comb generation in stable chip-based microresonators. Such a comb system will revolutionize applications, including multi-wavelength lasers, metrology, and spectroscopy. Aluminum gallium arsenide (AlGaAs) exhibits very h...

  16. Development of a virtual metrology method using plasma harmonics analysis

    Science.gov (United States)

    Jun, H.; Shin, J.; Kim, S.; Choi, H.

    2017-07-01

    A virtual metrology technique based on plasma harmonics is developed for predicting semiconductor processes. From a plasma process performed by 300 mm photoresist stripper equipment, a strong correlation is found between optical plasma harmonics intensities and the process results, such as the photoresist strip rate and strip non-uniformity. Based on this finding, a general process prediction model is developed. The developed virtual metrology model shows that the R-squared (R2) values between the measured and predicted process results are 95% and 64% for the photoresist strip rate and photoresist strip non-uniformity, respectively. This is the first research on process prediction based on optical plasma harmonics analysis, and the results can be applied to semiconductor processes such as dry etching and plasma enhanced chemical vapor deposition.

  17. Transformer-based design techniques for oscillators and frequency dividers

    CERN Document Server

    Luong, Howard Cam

    2016-01-01

    This book provides in-depth coverage of transformer-based design techniques that enable CMOS oscillators and frequency dividers to achieve state-of-the-art performance.  Design, optimization, and measured performance of oscillators and frequency dividers for different applications are discussed in detail, focusing on not only ultra-low supply voltage but also ultra-wide frequency tuning range and locking range.  This book will be an invaluable reference for anyone working or interested in CMOS radio-frequency or mm-Wave integrated circuits and systems.

  18. 基于 ADS1247的小型计量检定铂电阻温度计设计%The Miniature Platinum resistor temperature gauge for Metrology Calibration based on ADS1247r

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    To solve the problem of low precision and complex structure of platinum resistor temperature gauge for metrology calibration in the range of -30-300℃ ,this paper presents a design scheme of miniature platium resistor temperature gauge for metrology calibration based on ADS1247 of TI corp.The programmable constant-current source of ADS1247 is used as exciting source of platinum resistor.The programmable amplifier of ADS1247 is adopted to amplified the voltage drop of platinum resistor during the course of measurement,and the output voltage of amplifier was digitalized by a 24-bit analog-to-digital converter. According to the experiment,the measurement precision of platinum resistor temperature gauge can reach to 0.05℃ ,and the resolution can reach to 0.004℃.%  针对当前在-30-300℃范围内铂电阻计量检定温度计存在结构复杂、精度较低的问题,本文提出一种基于 TI 公司ADS1247的小型计量检定用铂电阻温度计的设计方案。将 ADS1247输出的可编程恒定电流作为铂电阻激励源。测量过程中,采用 ADS1247集成的可编程放大器放大铂电阻的电压降,并将放大器输出信号进行24位的 AD 转换。通过实验测试,基于ADS1247的铂电阻温度计精度可达到0.05℃,分辨率可达到0.004℃。

  19. Applications of surface metrology in firearm identification

    Science.gov (United States)

    Zheng, X.; Soons, J.; Vorburger, T. V.; Song, J.; Renegar, T.; Thompson, R.

    2014-01-01

    Surface metrology is commonly used to characterize functional engineering surfaces. The technologies developed offer opportunities to improve forensic toolmark identification. Toolmarks are created when a hard surface, the tool, comes into contact with a softer surface and causes plastic deformation. Toolmarks are commonly found on fired bullets and cartridge cases. Trained firearms examiners use these toolmarks to link an evidence bullet or cartridge case to a specific firearm, which can lead to a criminal conviction. Currently, identification is typically based on qualitative visual comparison by a trained examiner using a comparison microscope. In 2009, a report by the National Academies called this method into question. Amongst other issues, they questioned the objectivity of visual toolmark identification by firearms examiners. The National Academies recommended the development of objective toolmark identification criteria and confidence limits. The National Institute of Standards and Technology (NIST) have applied its experience in surface metrology to develop objective identification criteria, measurement methods, and reference artefacts for toolmark identification. NIST developed the Standard Reference Material SRM 2460 standard bullet and SRM 2461 standard cartridge case to facilitate quality control and traceability of identifications performed in crime laboratories. Objectivity is improved through measurement of surface topography and application of unambiguous surface similarity metrics, such as the maximum value (ACCFMAX) of the areal cross correlation function. Case studies were performed on consecutively manufactured tools, such as gun barrels and breech faces, to demonstrate that, even in this worst case scenario, all the tested tools imparted unique surface topographies that were identifiable. These studies provide scientific support for toolmark evidence admissibility in criminal court cases.

  20. SUBTLEX- AL: Albanian word frequencies based on film subtitles

    Directory of Open Access Journals (Sweden)

    Dr.Sc. Rrezarta Avdyli

    2013-06-01

    Full Text Available Recently several studies have shown that word frequency estimation based on subtitle files explains better the variance in word recognition performance than traditional words frequency estimates did. The present study aims to show this frequency estimate in Albanian from more than 2M words coming from film subtitles. Our results show high correlation between the RT from a LD study (120 stimuli and the SUBTLEX- AL, as well as, high correlation between this and the unique existing frequency list of a hundred more frequent Albanian words. These findings suggest that SUBTLEX-AL it is good frequency estimation, furthermore, this is the first database of frequency estimation in Albanian larger than 100 words.

  1. Optimization of measurement methods for a multi-frequency electromagnetic field from mobile phone base station using broadband EMF meter

    Directory of Open Access Journals (Sweden)

    Paweł Bieńkowski

    2015-10-01

    Full Text Available Background: This paper presents the characteristics of the mobile phone base station (BS as an electromagnetic field (EMF source. The most common system configurations with their construction are described. The parameters of radiated EMF in the context of the access to methods and other parameters of the radio transmission are discussed. Attention was also paid to antennas that are used in this technology. Material and Methods: The influence of individual components of a multi-frequency EMF, most commonly found in the BS surroundings, on the resultant EMF strength value indicated by popular broadband EMF meters was analyzed. The examples of metrological characteristics of the most common EMF probes and 2 measurement scenarios of the multisystem base station, with and without microwave relays, are shown. Results: The presented method for measuring the multi-frequency EMF using 2 broadband probes allows for the significant minimization of measurement uncertainty. Equations and formulas that can be used to calculate the actual EMF intensity from multi-frequency sources are shown. They have been verified in the laboratory conditions on a specific standard setup as well as in real conditions in a survey of the existing base station with microwave relays. Conclusions: Presented measurement methodology of multi-frequency EMF from BS with microwave relays, validated both in laboratory and real conditions. It has been proven that the described measurement methodology is the optimal approach to the evaluation of EMF exposure in BS surrounding. Alternative approaches with much greater uncertainty (precaution method or more complex measuring procedure (sources exclusion method are also presented. Med Pr 2015;66(5:701–712

  2. Generation of tunable, high repetition rate frequency combs with equalized spectra using carrier injection based silicon modulators

    Science.gov (United States)

    Nagarjun, K. P.; Selvaraja, Shankar Kumar; Supradeepa, V. R.

    2016-03-01

    High repetition-rate frequency combs with tunable repetition rate and carrier frequency are extensively used in areas like Optical communications, Microwave Photonics and Metrology. A common technique for their generation is strong phase modulation of a CW-laser. This is commonly implemented using Lithium-Niobate based modulators. With phase modulation alone, the combs have poor spectral flatness and significant number of missing lines. To overcome this, a complex cascade of multiple intensity and phase modulators are used. A comb generator on Silicon based on these principles is desirable to enable on-chip integration with other functionalities while reducing power consumption and footprint. In this work, we analyse frequency comb generation in carrier injection based Silicon modulators. We observe an interesting effect in these comb generators. Enhanced absorption accompanying carrier injection, an undesirable effect in data modulators, shapes the amplitude here to enable high quality combs from a single modulator. Thus, along with reduced power consumption to generate a specific number of lines, the complexity has also been significantly reduced. We use a drift-diffusion solver and mode solver (Silvaco TCAD) along with Soref-Bennett relations to calculate the variations in refractive indices and absorption of an optimized Silicon PIN - waveguide modulator driven by an unbiased high frequency (10 Ghz) voltage signal. Our simulations demonstrate that with a device length of 1 cm, a driving voltage of 2V and minor shaping with a passive ring-resonator filter, we obtain 37 lines with a flatness better than 5-dB across the band and power consumption an order of magnitude smaller than Lithium-Niobate modulators.

  3. On feasibility of regional frequency-based emergency control plans

    Energy Technology Data Exchange (ETDEWEB)

    Bevrani, H. [Department of Electrical and Computer Engineering, University of Kurdistan, Sanandaj, P.O. Box 416 (Iran); Ledwich, G.; Ford, J.J. [School of Engineering Systems, Queensland University of Technology, Brisbane, Qld 4001 (Australia); Dong, Z.Y. [Department of Electrical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon (China)

    2009-07-15

    Decentralized and regional load-frequency control of power systems operating in normal and near-normal conditions has been well studied; and several analysis/synthesis approaches have been developed during the last few decades. However in contingency and off-normal conditions, the existing emergency control plans, such as under-frequency load shedding, are usually applied in a centralized structure using a different analysis model. This paper discusses the feasibility of using frequency-based emergency control schemes based on tie-line measurements and local information available within a control area. The conventional load-frequency control model is generalized by considering the dynamics of emergency control/protection schemes and an analytic approach to analyze the regional frequency response under normal and emergency conditions is presented. (author)

  4. Novel Doppler Frequency Extraction Method Based on Time-Frequency Analysis and Morphological Operation

    Institute of Scientific and Technical Information of China (English)

    HOU Shu-juan; WU Si-liang

    2006-01-01

    A novel method of Doppler frequency extraction is proposed for Doppler radar scoring systems. The idea is that the time-frequency map can show how the Doppler frequency varies along the time-line, so the Doppler frequency extraction becomes curve detection in the image-view. A set of morphological operations are used to implement curve detection. And a map fusion scheme is presented to eliminate the influence of strong direct current (DC) component of echo signal during curve detection. The radar real-life data are used to illustrate the performance of the new approach. Experimental results show that the proposed method can over come the shortcomings of piecewise-processing-based FFT method and can improve the measuring precision of miss distance.

  5. Adjustment method for embedded metrology engine in an EM773 series microcontroller.

    Science.gov (United States)

    Blazinšek, Iztok; Kotnik, Bojan; Chowdhury, Amor; Kačič, Zdravko

    2015-09-01

    This paper presents the problems of implementation and adjustment (calibration) of a metrology engine embedded in NXP's EM773 series microcontroller. The metrology engine is used in a smart metering application to collect data about energy utilization and is controlled with the use of metrology engine adjustment (calibration) parameters. The aim of this research is to develop a method which would enable the operators to find and verify the optimum parameters which would ensure the best possible accuracy. Properly adjusted (calibrated) metrology engines can then be used as a base for variety of products used in smart and intelligent environments. This paper focuses on the problems encountered in the development, partial automatisation, implementation and verification of this method. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  6. Metrology in Pharmaceutical Industry - A Case Study

    Science.gov (United States)

    Yuvamoto, Priscila D.; Fermam, Ricardo K. S.; Nascimento, Elizabeth S.

    2016-07-01

    Metrology is recognized by improving production process, increasing the productivity, giving more reliability to the measurements and consequently, it impacts in the economy of a country. Pharmaceutical area developed GMP (Good Manufacture Practice) requeriments, with no introduction of metrological concepts. However, due to Nanomedicines, it is expected this approach and the consequent positive results. The aim of this work is to verify the level of metrology implementation in a Brazilian pharmaceutical industry, using a case study. The purpose is a better mutual comprehension by both areas, acting together and governmental support to robustness of Brazilian pharmaceutical area.

  7. 100 years of radionuclide metrology.

    Science.gov (United States)

    Judge, S M; Arnold, D; Chauvenet, B; Collé, R; De Felice, P; García-Toraño, E; Wätjen, U

    2014-05-01

    The discipline of radionuclide metrology at national standards institutes started in 1913 with the certification by Curie, Rutherford and Meyer of the first primary standards of radium. In early years, radium was a valuable commodity and the aim of the standards was largely to facilitate trade. The focus later changed to providing standards for the new wide range of radionuclides, so that radioactivity could be used for healthcare and industrial applications while minimising the risk to patients, workers and the environment. National measurement institutes responded to the changing demands by developing new techniques for realising primary standards of radioactivity. Looking ahead, there are likely to be demands for standards for new radionuclides used in nuclear medicine, an expansion of the scope of the field into quantitative imaging to facilitate accurate patient dosimetry for nuclear medicine, and an increasing need for accurate standards for radioactive waste management and nuclear forensics.

  8. Metrology for Fuel Cell Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Stocker, Michael [National Inst. of Standards and Technology, Gaithersburg, MD (United States); Stanfield, Eric [National Inst. of Standards and Technology, Gaithersburg, MD (United States)

    2015-02-04

    The project was divided into three subprojects. The first subproject is Fuel Cell Manufacturing Variability and Its Impact on Performance. The objective was to determine if flow field channel dimensional variability has an impact on fuel cell performance. The second subproject is Non-contact Sensor Evaluation for Bipolar Plate Manufacturing Process Control and Smart Assembly of Fuel Cell Stacks. The objective was to enable cost reduction in the manufacture of fuel cell plates by providing a rapid non-contact measurement system for in-line process control. The third subproject is Optical Scatterfield Metrology for Online Catalyst Coating Inspection of PEM Soft Goods. The objective was to evaluate the suitability of Optical Scatterfield Microscopy as a viable measurement tool for in situ process control of catalyst coatings.

  9. National Needs for Appearance Metrology

    Science.gov (United States)

    Nadal, Maria E.

    2003-04-01

    Appearance greatly influences a customer's judgement of the quality and acceptability of manufactured products, as yearly there is approximately $700 billion worth of shipped goods for which overall appearance is critical to their sale. For example, appearance is reported to be a major factor in about half of automobile purchases. The appearance of an object is the result of a complex interaction of the light field incident upon the object, the scattering and absorption properties of the object, and human perception. The measurable attributes of appearance are divided into color (hue, saturation, and lightness) and geometry (gloss, haze). The nature of the global economy has increased international competition and the need to improve the quality of many manufactured products. Since the manufacturing and marketing of these products is international in scope, the lack of national appearance standard artifacts and measurement protocols results in a direct loss to the supplier. One of the primary missions of the National Institute of Standards and Technology (NIST) is to strengthen the U.S. economy by working with industry to develop and apply technology, measurements and standards. The NIST Physics Laboratory has established an appearance metrology laboratory. This new laboratory provides calibration services for 0^o/45^o color standards and 20^o°, 60^o°, and 85^o° specular gloss, and research in the colorimetric characterization of gonioapparent including a new Standard Reference Material for metallic coatings (SRM 2017) and measurement protocols for pearlescent coatings. These services are NIST's first appearance metrology efforts in many years; a response to needs articulated by industry. These services are designed to meet demands for improved measurements and standards to enhance the acceptability of final products since appearance often plays a major role in their acceptability.

  10. Weak Signal Frequency Detection Method Based on Generalized Duffing Oscillator

    Institute of Scientific and Technical Information of China (English)

    SHI Si-Hong; YUAN Yong; WANG Hui-Qi; LUO Mao-Kang

    2011-01-01

    @@ The sensitive characteristic to the initial value of chaos system sufficiently demonstrates the superiority in weak signal parameters detection.Analyzing the current chaos-based frequency detection method, a novel generalized Duffing equation is proposed to detect weak signal frequency.By choosing a suitable adjusting factor, when the outside driving force frequency is equal to that of the detected signal, the generalized Duffing oscillator is in great period state, which can obtain the frequency information of the detected signal.The simulation results indicate this method is rapidly convenient and shows better accuracy.%The sensitive characteristic to the initial value of chaos system sufficiently demonstrates the superiority in weak signal parameters detection. Analyzing the current chaos-based frequency detection method, a novel generalized Duffing equation is proposed to detect weak signal frequency. By choosing a suitable adjusting factor, when the outside driving force frequency is equal to that of the detected signal, the generalized Duffing oscillator is in great period state, which can obtain the frequency information of the detected signal. The simulation results indicate this method is rapidly convenient and shows better accuracy.

  11. A Knowledge-Navigation System for Dimensional Metrology.

    Science.gov (United States)

    Moncarz, Howard T

    2002-01-01

    Geometric dimensioning and tolerancing (GD&T) is a method to specify the dimensions and form of a part so that it will meet its design intent. GD&T is difficult to master for two main reasons. First, it is based on complex 3D geometric entities and relationships. Second, the geometry is associated with a large, diverse knowledge base of dimensional metrology with many interconnections. This paper describes an approach to create a dimensional metrology knowledge base that is organized around a set of key concepts and to represent those concepts as virtual objects that can be navigated with interactive, computer visualization techniques to access the associated knowledge. The approach can enable several applications. First is the application to convey the definition and meaning of GD&T over a broad range of tolerance types. Second is the application to provide a visualization of dimensional metrology knowledge within a control hierarchy of the inspection process. Third is the application to show the coverage of interoperability standards to enable industry to make decisions on standards development and harmonization efforts. A prototype system has been implemented to demonstrate the principles involved in the approach.

  12. Relativistic quantum metrology: exploiting relativity to improve quantum measurement technologies.

    Science.gov (United States)

    Ahmadi, Mehdi; Bruschi, David Edward; Sabín, Carlos; Adesso, Gerardo; Fuentes, Ivette

    2014-05-22

    We present a framework for relativistic quantum metrology that is useful for both Earth-based and space-based technologies. Quantum metrology has been so far successfully applied to design precision instruments such as clocks and sensors which outperform classical devices by exploiting quantum properties. There are advanced plans to implement these and other quantum technologies in space, for instance Space-QUEST and Space Optical Clock projects intend to implement quantum communications and quantum clocks at regimes where relativity starts to kick in. However, typical setups do not take into account the effects of relativity on quantum properties. To include and exploit these effects, we introduce techniques for the application of metrology to quantum field theory. Quantum field theory properly incorporates quantum theory and relativity, in particular, at regimes where space-based experiments take place. This framework allows for high precision estimation of parameters that appear in quantum field theory including proper times and accelerations. Indeed, the techniques can be applied to develop a novel generation of relativistic quantum technologies for gravimeters, clocks and sensors. As an example, we present a high precision device which in principle improves the state-of-the-art in quantum accelerometers by exploiting relativistic effects.

  13. Optical metrology techniques for dimensional stability measurements

    NARCIS (Netherlands)

    Ellis, Jonathan David

    2010-01-01

    This thesis work is optical metrology techniques to determine material stability. In addition to displacement interferometry, topics such as periodic nonlinearity, Fabry-Perot interferometry, refractometry, and laser stabilization are covered.

  14. Optical metrology techniques for dimensional stability measurements

    NARCIS (Netherlands)

    Ellis, Jonathan David

    2010-01-01

    This thesis work is optical metrology techniques to determine material stability. In addition to displacement interferometry, topics such as periodic nonlinearity, Fabry-Perot interferometry, refractometry, and laser stabilization are covered.

  15. Improving metrology for micro-optics manufacturing

    Science.gov (United States)

    Davies, Angela D.; Bergner, Brent C.; Gardner, Neil W.

    2003-11-01

    Metrology is one of the critical enabling technologies for realizing the full market potential for micro-optical systems. Measurement capabilities are currently far behind present and future needs. Much of today"s test equipment was developed for the micro-electronics industry and is not optimized for micro-optic materials and geometries. Metrology capabilities currently limit the components that can be realized, in many cases. Improved testing will be come increasingly important as the technology moves to integration where it will become important to "test early and test often" to achieve high yields. In this paper, we focus on micro-refractive components in particular, and describe measurement challenges for this class of components and current and future needs. We also describe a new micro-optics metrology research program at UNC Charlotte under the Center for Precision Metrology and the new Center for Optoelectronics and Optical Communications to address these needs.

  16. Metrological Characterisation of a Fast Digital Integrator for Magnetic Measurements at CERN

    CERN Document Server

    Arpaia, P; Masi, A; Spiezia, G

    2007-01-01

    A Fast Digital Integrator (FDI) was designed to satisfy new more demanding requirements of dynamic accuracy and trigger frequency in magnetic measurements based on rotating coil systems for analyzing superconducting magnets in particle accelerators. In particular, in flux measurement, a bandwidth up to 50-100 kHz and a dynamic accuracy of 10 ppm are targeted. In this paper, results of static and dynamic metrological characterization of the FDI prototype and of the Portable Digital Integrator (PDI), heavely used at CERN and in many sub-nuclear laboratories, are compared. Preliminary results show how the initial prototype of FDI is already capable of both overcoming dynamic performance of PDI and covering operating regions inaccessible before.

  17. Nanomanufacturing metrology for cellulosic nanomaterials: an update

    Science.gov (United States)

    Postek, Michael T.

    2014-08-01

    The development of the metrology and standards for advanced manufacturing of cellulosic nanomaterials (or basically, wood-based nanotechnology) is imperative to the success of this rising economic sector. Wood-based nanotechnology is a revolutionary technology that will create new jobs and strengthen America's forest-based economy through industrial development and expansion. It allows this, previously perceived, low-tech industry to leap-frog directly into high-tech products and processes and thus improves its current economic slump. Recent global investments in nanotechnology programs have led to a deeper appreciation of the high performance nature of cellulose nanomaterials. Cellulose, manufactured to the smallest possible-size ( 2 nm x 100 nm), is a high-value material that enables products to be lighter and stronger; have less embodied energy; utilize no catalysts in the manufacturing, are biologically compatible and, come from a readily renewable resource. In addition to the potential for a dramatic impact on the national economy - estimated to be as much as $250 billion worldwide by 2020 - cellulose-based nanotechnology creates a pathway for expanded and new markets utilizing these renewable materials. The installed capacity associated with the US pulp and paper industry represents an opportunity, with investment, to rapidly move to large scale production of nano-based materials. However, effective imaging, characterization and fundamental measurement science for process control and characterization are lacking at the present time. This talk will discuss some of these needed measurements and potential solutions.

  18. Ultracold Molecules in Lattices for Metrology and Precision Measurements

    Science.gov (United States)

    Reinaudi, Gael; Osborn, Chris; McDonald, Mickey; Wang, Dili; Zelevinsky, Tanya

    2012-06-01

    Ultracold diatomic molecules offer exciting possibilities for studies of novel states of matter, quantum information, and metrology. Two-electron-atom based molecules are particularly promising for precision measurements, such as molecular time metrology and variations of the proton-electron mass ratio. We present an experimental setup that allows for the photoassociation, in an optical lattice, of strontium atoms into molecules using the narrow singlet-triplet transitions. We feature newly observed two-photon photoassociation to deeply bound molecular levels, as well as the study of the lifetime of such molecules in lattices, which is a determining factor concerning the practical use of this system. Other characteristics of our setup are presented, such as a computer controlled permanent-magnet Zeeman slower optimized with a genetic algorithm.

  19. Metrology for industrial quantum communications: the MIQC project

    Science.gov (United States)

    Rastello, M. L.; Degiovanni, I. P.; Sinclair, A. G.; Kück, S.; Chunnilall, C. J.; Porrovecchio, G.; Smid, M.; Manoocheri, F.; Ikonen, E.; Kubarsepp, T.; Stucki, D.; Hong, K. S.; Kim, S. K.; Tosi, A.; Brida, G.; Meda, A.; Piacentini, F.; Traina, P.; Natsheh, A. Al; Cheung, J. Y.; Müller, I.; Klein, R.; Vaigu, A.

    2014-12-01

    The ‘Metrology for Industrial Quantum Communication Technologies’ project (MIQC) is a metrology framework that fosters development and market take-up of quantum communication technologies and is aimed at achieving maximum impact for the European industry in this area. MIQC is focused on quantum key distribution (QKD) technologies, the most advanced quantum-based technology towards practical application. QKD is a way of sending cryptographic keys with absolute security. It does this by exploiting the ability to encode in a photon's degree of freedom specific quantum states that are noticeably disturbed if an eavesdropper trying to decode it is present in the communication channel. The MIQC project has started the development of independent measurement standards and definitions for the optical components of QKD system, since one of the perceived barriers to QKD market success is the lack of standardization and quality assurance.

  20. Quantum enhanced metrology and the geometry of quantum channels

    CERN Document Server

    Demkowicz-Dobrzanski, Rafal; Kolodynski, Jan

    2012-01-01

    Lower bounds on the estimation uncertainty are derived for quantum metrological schemes in the presence of decoherence showing that Heisenberg scaling is generically lost even for infinitesimal level of noise. Unlike in other methods, calculation of the bounds is straightforward and requires only a simple analysis of the mathematical structure of the decoherence process. In some models, e.g. atomic clocks frequency calibration with dephasing, calculation may be performed using an intuitive geometric picture. All that is necessary is a "distance" of a point representing the decoherence process from the boundary of the set of all quantum channels.

  1. Reliability Based Optimization of Composite Laminates for Frequency Constraint

    Institute of Scientific and Technical Information of China (English)

    Wu Hao; Yan Ying; Liu Yujia

    2008-01-01

    The reliability based optimization (RBO) issue of composite laminates under fundamental frequency constraint is studied. Considering the uncertainties of material properties, the frequency constraint reliability of the structure is evaluated by the combination of response surface method (RSM) and finite element method. An optimization algorithm is developed based on the mechanism of laminate frequency characteristics, to optimize the laminate in terms of the ply amount and orientation angles. Numerical examples of composite laminates and cylindrical shell illustrate the advantages of the present optimization algorithm on the efficiency and applicability respects.The optimal solutions of RBO are obviously different from the deterministic optimization results, and the necessity of considering material property uncertainties in the composite srtuctural frequency constraint optimization is revealed.

  2. New Iterated Decoding Algorithm Based on Differential Frequency Hopping System

    Institute of Scientific and Technical Information of China (English)

    LIANG Fu-lin; LUO Wei-xiong

    2005-01-01

    A new iterated decoding algorithm is proposed for differential frequency hopping (DFH) encoder concatenated with multi-frequency shift-key (MFSK) modulator. According to the character of the frequency hopping (FH) pattern trellis produced by DFH function, maximum a posteriori (MAP) probability theory is applied to realize the iterate decoding of it. Further, the initial conditions for the new iterate algorithm based on MAP algorithm are modified for better performance. Finally, the simulation result compared with that from traditional algorithms shows good anti-interference performance.

  3. Cooperative Game Study of Airlines Based on Flight Frequency Optimization

    Directory of Open Access Journals (Sweden)

    Wanming Liu

    2014-01-01

    Full Text Available By applying the game theory, the relationship between airline ticket price and optimal flight frequency is analyzed. The paper establishes the payoff matrix of the flight frequency in noncooperation scenario and flight frequency optimization model in cooperation scenario. The airline alliance profit distribution is converted into profit distribution game based on the cooperation game theory. The profit distribution game is proved to be convex, and there exists an optimal distribution strategy. The results show that joining the airline alliance can increase airline whole profit, the change of negotiated prices and cost is beneficial to profit distribution of large airlines, and the distribution result is in accordance with aviation development.

  4. Musical Sound Separation Based on Binary Time-Frequency Masking

    Directory of Open Access Journals (Sweden)

    Wang DeLiang

    2009-01-01

    Full Text Available The problem of overlapping harmonics is particularly acute in musical sound separation and has not been addressed adequately. We propose a monaural system based on binary time-frequency masking with an emphasis on robust decisions in time-frequency regions, where harmonics from different sources overlap. Our computational auditory scene analysis system exploits the observation that sounds from the same source tend to have similar spectral envelopes. Quantitative results show that utilizing spectral similarity helps binary decision making in overlapped time-frequency regions and significantly improves separation performance.

  5. Frequency Estimator Performance for a Software-Based Beacon Receiver

    Science.gov (United States)

    Zemba, Michael J.; Morse, Jacquelynne Rose; Nessel, James A.; Miranda, Felix

    2014-01-01

    As propagation terminals have evolved, their design has trended more toward a software-based approach that facilitates convenient adjustment and customization of the receiver algorithms. One potential improvement is the implementation of a frequency estimation algorithm, through which the primary frequency component of the received signal can be estimated with a much greater resolution than with a simple peak search of the FFT spectrum. To select an estimator for usage in a QV-band beacon receiver, analysis of six frequency estimators was conducted to characterize their effectiveness as they relate to beacon receiver design.

  6. NIF Target Assembly Metrology Methodology and Results

    Energy Technology Data Exchange (ETDEWEB)

    Alger, E. T. [General Atomics, San Diego, CA (United States); Kroll, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Dzenitis, E. G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Montesanti, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hughes, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Swisher, M. [IAP, Livermore, CA (United States); Taylor, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Segraves, K. [IAP, Livermore, CA (United States); Lord, D. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Reynolds, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Castro, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Edwards, G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2011-01-01

    During our inertial confinement fusion (ICF) experiments at the National Ignition Facility (NIF) we require cryogenic targets at the 1-cm scale to be fabricated, assembled, and metrologized to micron-level tolerances. During assembly of these ICF targets, there are physical dimensmetrology is completed using optical coordinate measurement machines that provide repeatable measurements with micron precision, while also allowing in-process data collection for absolute accuracy in assembly. To date, 51 targets have been assembled and metrologized, and 34 targets have been successfully fielded on NIF relying on these metrology data. In the near future, ignition experiments on NIF will require tighter tolerances and more demanding target assembly and metrology capability. Metrology methods, calculations, and uncertainty estimates will be discussed. Target diagnostic port alignment, target position, and capsule location results will be reviewed for the 2009 Energetics Campaign. The information is presented via control charts showing the effect of process improvements that were made during target production. Certain parameters, including capsule position, met the 2009 campaign specifications but will have much tighter requirements in the future. Finally, in order to meet these new requirements assembly process changes and metrology capability upgrades will be necessary.

  7. X-ray optics metrology limited by random noise, instrumental drifts, and systematic errors

    Energy Technology Data Exchange (ETDEWEB)

    Yashchuk, Valeriy V.; Anderson, Erik H.; Barber, Samuel K.; Cambie, Rossana; Celestre, Richard; Conley, Raymond; Goldberg, Kenneth A.; McKinney, Wayne R.; Morrison, Gregory; Takacs, Peter Z.; Voronov, Dmitriy L.; Yuan, Sheng; Padmore, Howard A.

    2010-07-09

    Continuous, large-scale efforts to improve and develop third- and forth-generation synchrotron radiation light sources for unprecedented high-brightness, low emittance, and coherent x-ray beams demand diffracting and reflecting x-ray optics suitable for micro- and nano-focusing, brightness preservation, and super high resolution. One of the major impediments for development of x-ray optics with the required beamline performance comes from the inadequate present level of optical and at-wavelength metrology and insufficient integration of the metrology into the fabrication process and into beamlines. Based on our experience at the ALS Optical Metrology Laboratory, we review the experimental methods and techniques that allow us to mitigate significant optical metrology problems related to random, systematic, and drift errors with super-high-quality x-ray optics. Measurement errors below 0.2 mu rad have become routine. We present recent results from the ALS of temperature stabilized nano-focusing optics and dedicated at-wavelength metrology. The international effort to develop a next generation Optical Slope Measuring System (OSMS) to address these problems is also discussed. Finally, we analyze the remaining obstacles to further improvement of beamline x-ray optics and dedicated metrology, and highlight the ways we see to overcome the problems.

  8. Laser frequency stabilization based on Sagnac interferometric spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Hui Yan; Guoqing Yang; Jin Wang; Mingsheng Zhan

    2008-01-01

    @@ A simple method based on Sagnac interferometric spectroscopy (SIS) is applied for frequency stabilization of diode lasers. Sagnac interferometric spectra of rubidium vapor are investigated both theoretically and experimentally. The interference signal at the output of the Sagnac interferometer displays a sharp dispersion feature near the atomic resonance. This dispersion curve is used as the feedback error signal to stabilize the laser frequency. Linewidth of a diode laser is stabilized down to 1 MHz by this modulation-free method.

  9. Design and industrial production of frequency standards in the USSR

    Science.gov (United States)

    Demidov, Nikolai A.; Uljanov, Adolph A.

    1990-01-01

    Some aspects of research development and production of quantum frequency standards, carried out in QUARTZ Research and Production Association (RPA), Gorky, U.S.S.R., were investigated for the last 25 to 30 years. During this period a number of rubidium and hydrogen frequency standards, based on the active maser, were developed and put into production. The first industrial model of a passive hydrogen maser was designed in the last years. Besides frequency standards for a wide application range, RPA QUARTZ investigates metrological frequency standards--cesium standards with cavity length 1.9 m and hydrogen masers with a flexible storage bulb.

  10. Design and industrial production of frequency standards in the USSR

    Science.gov (United States)

    Demidov, Nikolai A.; Uljanov, Adolph A.

    1990-01-01

    Some aspects of research development and production of quantum frequency standards, carried out in QUARTZ Research and Production Association (RPA), Gorky, U.S.S.R., were investigated for the last 25 to 30 years. During this period a number of rubidium and hydrogen frequency standards, based on the active maser, were developed and put into production. The first industrial model of a passive hydrogen maser was designed in the last years. Besides frequency standards for a wide application range, RPA QUARTZ investigates metrological frequency standards--cesium standards with cavity length 1.9 m and hydrogen masers with a flexible storage bulb.

  11. Audio Effects Based on Biorthogonal Time-Varying Frequency Warping

    Directory of Open Access Journals (Sweden)

    Cavaliere Sergio

    2001-01-01

    Full Text Available We illustrate the mathematical background and musical use of a class of audio effects based on frequency warping. These effects alter the frequency content of a signal via spectral mapping. They can be implemented in dispersive tapped delay lines based on a chain of all-pass filters. In a homogeneous line with first-order all-pass sections, the signal formed by the output samples at a given time is related to the input via the Laguerre transform. However, most musical signals require a time-varying frequency modification in order to be properly processed. Vibrato in musical instruments or voice intonation in the case of vocal sounds may be modeled as small and slow pitch variations. Simulation of these effects requires techniques for time-varying pitch and/or brightness modification that are very useful for sound processing. The basis for time-varying frequency warping is a time-varying version of the Laguerre transformation. The corresponding implementation structure is obtained as a dispersive tapped delay line, where each of the frequency dependent delay element has its own phase response. Thus, time-varying warping results in a space-varying, inhomogeneous, propagation structure. We show that time-varying frequency warping is associated to an expansion over biorthogonal sets generalizing the discrete Laguerre basis. Slow time-varying characteristics lead to slowly varying parameter sequences. The corresponding sound transformation does not suffer from discontinuities typical of delay lines based on unit delays.

  12. Subpixel edge detection method based on low-frequency filtering

    Science.gov (United States)

    Bylinsky, Yosip Y.; Kotyra, Andrzej; Gromaszek, Konrad; Iskakova, Aigul

    2016-09-01

    A method of edge detection in images is proposed basing that based on low-frequency filtering. The method uses polynomial interpolation to determine the coordinates of the edge point with subpixel accuracy. Some experiments have been results also have been provided.

  13. Review of the mathematical foundations of data fusion techniques in surface metrology

    Science.gov (United States)

    Wang, Jian; Leach, Richard K.; Jiang, X.

    2015-06-01

    The recent proliferation of engineered surfaces, including freeform and structured surfaces, is challenging current metrology techniques. Measurement using multiple sensors has been proposed to achieve enhanced benefits, mainly in terms of spatial frequency bandwidth, which a single sensor cannot provide. When using data from different sensors, a process of data fusion is required and there is much active research in this area. In this paper, current data fusion methods and applications are reviewed, with a focus on the mathematical foundations of the subject. Common research questions in the fusion of surface metrology data are raised and potential fusion algorithms are discussed.

  14. Optical vortex metrology: Are phase singularities foes or friends in optical metrology?

    DEFF Research Database (Denmark)

    Takeda, M.; Wang, W.; Hanson, Steen Grüner;

    2008-01-01

    We raise an issue whether phase singularities are foes or friends in optical metrology, and give an answer by introducing the principle and applications of a new technique which we recently proposed for displacement and flow measurements. The technique is called optical vortex metrology because...

  15. Nuclear Technology. Course 26: Metrology. Module 27-7, Statistical Techniques in Metrology.

    Science.gov (United States)

    Espy, John; Selleck, Ben

    This seventh in a series of eight modules for a course titled Metrology focuses on descriptive and inferential statistical techniques in metrology. The module follows a typical format that includes the following sections: (1) introduction, (2) module prerequisites, (3) objectives, (4) notes to instructor/student, (5) subject matter, (6) materials…

  16. Nuclear Technology. Course 27: Metrology. Module 27-1, Fundamentals of Metrology.

    Science.gov (United States)

    Selleck, Ben; Espy, John

    This first in a series of eight modules for a course titled Metrology describes the fundamentals of metrology as they pertain to dimensional inspection. The module follows a typical format that includes the following sections: (1) introduction, (2) module prerequisites, (3) objectives, (4) notes to instructor/student, (5) subject matter, (6)…

  17. Frequency-tunable terahertz absorbers based on graphene metasurface

    Science.gov (United States)

    Chen, Ming; Sun, Wei; Cai, Jianjin; Chang, Linzi; Xiao, Xiaofei

    2017-01-01

    We present efficient designs of graphene-based thin absorbers, which are capable of near-unity absorption of the incident electromagnetic waves in the terahertz regime. Primarily, a single-frequency absorber is proposed. Subsequently, by simply stacking the double layer graphene metasurface with various geometric dimensions, the dual-frequency absorption and broadband absorption are realized respectively. Results demonstrate that the absorptivity of the single-frequency absorber reaches 99.51% at 2.71 THz when the Fermi energy is fixed at 0.9 eV. The dual-frequency absorber can simultaneously work at two frequencies with its absorptivity being 98.94% for 1.99 THz and 99.1% for 2.69 THz. The bandwidth of absorption rate above 90% expands three times when compared with the former single-frequency absorber. Additionally, it possesses the polarization-insensitive and large angle tolerance properties. More importantly, the absorption frequency can be dynamically controlled by adjusting Fermi energy levels without varying the nanostructure, which exhibits tremendous application values in many fields.

  18. A wide-range metrology AFM and its applications

    Science.gov (United States)

    Lin, Xiaofeng; Zhang, Haijun; Zhang, Dongxian

    2005-02-01

    In view of the fact that the application field of a dual tunneling-unit scanning tunneling microscope (DTU-STM) was strongly limited by sample conductivity, a dual imaging unit atomic force microscope (DIU-AFM) was developed for wide-range nano-metrology. A periodic grating is employed as a reference sample. The DIU-AFM simultaneously scans the grating and a test sample by using one single XY scanner. Their images thus have the same lateral size, and the length of the test sample image can be precisely measured by counting the number of periodic features of the reference grating. We further developed a new method of implementing wide-range nano-metrology. By alternatively moving the XY scanner in the X direction using a step motor, a series of pairs of images are obtained and can be spliced into two wide-range reference and test ones, respectively. Again, the two spliced images are of the same size, and the length of test image can be measured based on the reference grating features. In this way, wide-range metrology with nanometer order accuracy is successfully realized.

  19. An innovative bifocal metrology system for aerospace applications

    Science.gov (United States)

    Bresciani, F.

    2016-11-01

    In this paper an innovative space metrology system which objective is to measure the mutual arrangement between two spacecrafts is descripted. It is a simple and robust system that makes possible relative attitude measurements between 2 satellites in formation flying with coarse and fine accuracies. Generally, in formation flying mission it's necessary to have a satellite attitude control whose accuracy depends on their relative distance. The proposed metrology is based on an innovative optical projective system embedded on satellite 1 and a target composed by several light sources mounted on satellite 2. Optical system concurrently projects on a CCD two images of the target and from relative position of the light sources on the CCD image plane it's possible to detect position and attitude of the S2. Basic element of innovation of this versatile metrology concept is the possibility to work on a very large S/Cs range distance (~10 m-15 km) and to determinate the relative attitude and position of two spacecrafts on all six degree of freedom in a very simple and fast way.

  20. Single-shot adaptive measurement for quantum-enhanced metrology

    Science.gov (United States)

    Palittpongarnpim, Pantita; Wittek, Peter; Sanders, Barry C.

    2016-09-01

    Quantum-enhanced metrology aims to estimate an unknown parameter such that the precision scales better than the shot-noise bound. Single-shot adaptive quantum-enhanced metrology (AQEM) is a promising approach that uses feedback to tweak the quantum process according to previous measurement outcomes. Techniques and formalism for the adaptive case are quite different from the usual non-adaptive quantum metrology approach due to the causal relationship between measurements and outcomes. We construct a formal framework for AQEM by modeling the procedure as a decision-making process, and we derive the imprecision and the Craḿer- Rao lower bound with explicit dependence on the feedback policy. We also explain the reinforcement learning approach for generating quantum control policies, which is adopted due to the optimal policy being non-trivial to devise. Applying a learning algorithm based on differential evolution enables us to attain imprecision for adaptive interferometric phase estimation, which turns out to be SQL when non-entangled particles are used in the scheme.

  1. XPS-XRF hybrid metrology enabling FDSOI process

    Science.gov (United States)

    Hossain, Mainul; Subramanian, Ganesh; Triyoso, Dina; Wahl, Jeremy; Mcardle, Timothy; Vaid, Alok; Bello, A. F.; Lee, Wei Ti; Klare, Mark; Kwan, Michael; Pois, Heath; Wang, Ying; Larson, Tom

    2016-03-01

    Planar fully-depleted silicon-on-insulator (FDSOI) technology potentially offers comparable transistor performance as FinFETs. pFET FDOSI devices are based on a silicon germanium (cSiGe) layer on top of a buried oxide (BOX). Ndoped interfacial layer (IL), high-k (HfO2) layer and the metal gate stacks are then successively built on top of the SiGe layer. In-line metrology is critical in precisely monitoring the thickness and composition of the gate stack and associated underlying layers in order to achieve desired process control. However, any single in-line metrology technique is insufficient to obtain the thickness of IL, high-k, cSiGe layers in addition to Ge% and N-dose in one single measurement. A hybrid approach is therefore needed that combines the capabilities of more than one measurement technique to extract multiple parameters in a given film stack. This paper will discuss the approaches, challenges, and results associated with the first-in-industry implementation of XPS-XRF hybrid metrology for simultaneous detection of high-k thickness, IL thickness, N-dose, cSiGe thickness and %Ge, all in one signal measurement on a FDSOI substrate in a manufacturing fab. Strong correlation to electrical data for one or more of these measured parameters will also be presented, establishing the reliability of this technique.

  2. Distributed Frequency Control of Prosumer-Based Electric Energy Systems

    Energy Technology Data Exchange (ETDEWEB)

    Nazari, MH; Costello, Z; Feizollahi, MJ; Grijalva, S; Egerstedt, M

    2014-11-01

    In this paper, we propose a distributed frequency regulation framework for prosumer-based electric energy systems, where a prosumer (producer-consumer) is defined as an intelligent agentwhich can produce, consume, and/or store electricity. Despite the frequency regulators being distributed, stability can be ensured while avoiding inter-area oscillations using a limited control effort. To achieve this, a fully distributed one-step model-predictive control protocol is proposed and analyzed, whereby each prosumer communicates solely with its neighbors in the network. The efficacy of the proposed frequency regulation framework is shown through simulations on two real-world electric energy systems of different scale and complexity. We show that prosumers can indeed bring frequency and power deviations to their desired values after small perturbations.

  3. Spacetime Metrology with LISA Pathfinder

    CERN Document Server

    Congedo, Giuseppe

    2012-01-01

    LISA is the proposed ESA-NASA gravitational wave detector in the 0.1 mHz - 0.1 Hz band. LISA Pathfinder is the down-scaled version of a single LISA arm. The arm -- named Doppler link -- can be treated as a differential accelerometer, measuring the relative acceleration between test masses. LISA Pathfinder -- the in-flight test of the LISA instrumentation -- is currently in the final implementation and planned to be launched in 2014. It will set stringent constraints on the ability to put test masses in geodesic motion to within the required differential acceleration of 3\\times10^{-14} m s^{-2} Hz^{-1/2} and track their relative motion to within the required differential displacement measurement noise of 9\\times10^{-12} m Hz^{-1/2}, around 1 mHz. Given the scientific objectives, it will carry out -- for the first time with such high accuracy required for gravitational wave detection -- the science of spacetime metrology, in which the Doppler link between two free-falling test masses measures the curvature. Thi...

  4. Genetic Algorithm based Decentralized PI Type Controller: Load Frequency Control

    Science.gov (United States)

    Dwivedi, Atul; Ray, Goshaidas; Sharma, Arun Kumar

    2016-12-01

    This work presents a design of decentralized PI type Linear Quadratic (LQ) controller based on genetic algorithm (GA). The proposed design technique allows considerable flexibility in defining the control objectives and it does not consider any knowledge of the system matrices and moreover it avoids the solution of algebraic Riccati equation. To illustrate the results of this work, a load-frequency control problem is considered. Simulation results reveal that the proposed scheme based on GA is an alternative and attractive approach to solve load-frequency control problem from both performance and design point of views.

  5. Carbon nanotube transistor based high-frequency electronics

    Science.gov (United States)

    Schroter, Michael

    At the nanoscale carbon nanotubes (CNTs) have higher carrier mobility and carrier velocity than most incumbent semiconductors. Thus CNT based field-effect transistors (FETs) are being considered as strong candidates for replacing existing MOSFETs in digital applications. In addition, the predicted high intrinsic transit frequency and the more recent finding of ways to achieve highly linear transfer characteristics have inspired investigations on analog high-frequency (HF) applications. High linearity is extremely valuable for an energy efficient usage of the frequency spectrum, particularly in mobile communications. Compared to digital applications, the much more relaxed constraints for CNT placement and lithography combined with already achieved operating frequencies of at least 10 GHz for fabricated devices make an early entry in the low GHz HF market more feasible than in large-scale digital circuits. Such a market entry would be extremely beneficial for funding the development of production CNTFET based process technology. This talk will provide an overview on the present status and feasibility of HF CNTFET technology will be given from an engineering point of view, including device modeling, experimental results, and existing roadblocks. Carbon nanotube transistor based high-frequency electronics.

  6. Metrology Sampling Strategies for Process Monitoring Applications

    KAUST Repository

    Vincent, Tyrone L.

    2011-11-01

    Shrinking process windows in very large scale integration semiconductor manufacturing have already necessitated the development of control systems capable of addressing sub-lot-level variation. Within-wafer control is the next milestone in the evolution of advanced process control from lot-based and wafer-based control. In order to adequately comprehend and control within-wafer spatial variation, inline measurements must be performed at multiple locations across the wafer. At the same time, economic pressures prompt a reduction in metrology, for both capital and cycle-time reasons. This paper explores the use of modeling and minimum-variance prediction as a method to select the sites for measurement on each wafer. The models are developed using the standard statistical tools of principle component analysis and canonical correlation analysis. The proposed selection method is validated using real manufacturing data, and results indicate that it is possible to significantly reduce the number of measurements with little loss in the information obtained for the process control systems. © 2011 IEEE.

  7. Photonics-based tunable and broadband radio frequency converter

    Science.gov (United States)

    Borges, Ramon Maia; Mazzer, Daniel; Rufino Marins, Tiago Reis; Sodré, Arismar Cerqueira

    2016-03-01

    This paper is regarding the concept and development of a photonics-based tunable and broadband radio frequency converter (PBRC). It employs an external modulation technique to generate and reconfigure its output frequency, a digital circuit to manage the modulators' bias voltages, and an optical interface for connecting it to optical-wireless networks based on radio-over-fiber technology. The proposed optoelectronic device performs photonics-based upconversion and downconversion as a function of the local oscillator frequency and modulators' bias points. Experimental results demonstrate a radiofrequency (RF) carrier conversion with spectral purity over the frequency range from 750 MHz to 6.0 GHz, as well as the integration of the photonics-based converter with an optical backhaul based on a 1.5-km single-mode fiber from a geographically distributed optical network. Low phase noise and distortion absence illustrate its applicability for convergent and reconfigurable optical wireless communications. A potential application relies on the use of PBRC in convergent optical wireless networks to dynamically provide RF carriers as a function of the telecom operator demand and radio propagation environment.

  8. Skyrmion-based high-frequency signal generator

    Science.gov (United States)

    Luo, Shijiang; Zhang, Yue; Shen, Maokang; Ou-Yang, Jun; Yan, Baiqian; Yang, Xiaofei; Chen, Shi; Zhu, Benpeng; You, Long

    2017-03-01

    Many concepts for skyrmion-based devices have been proposed, and most of their possible applications are based on the motion of skyrmions driven by a dc current in an area with a constricted geometry. However, skyrmion motion driven by a pulsed current has not been investigated so far. In this work, we propose a skyrmion-based high-frequency signal generator based on the pulsed-current-driven circular motion of skyrmions in a square-shaped film by micromagnetic simulation. The results indicate that skyrmions can move in a closed curve with central symmetry. The trajectory and cycle period can be adjusted by tuning the size of the film, the current density, the Dzyaloshinskii-Moriya interaction constant, and the local in-plane magnetic anisotropy. The period can be tuned from several nanoseconds to tens of nanoseconds, which offers the possibility to prepare high-frequency signal generator based on skyrmions.

  9. Metrology for Radiological Early Warning Networks in Europe ("METROERM")-A Joint European Metrology Research Project.

    Science.gov (United States)

    Neumaier, Stefan; Dombrowski, Harald; Kessler, Patrick

    2016-08-01

    As a consequence of the Chernobyl nuclear power plant accident in 1986, all European countries have installed automatic dosimetry network stations as well as air sampling systems for the monitoring of airborne radioactivity. In Europe, at present, almost 5,000 stations measure dose rate values in nearly real time. In addition, a few hundred air samplers are operated. Most of them need extended accumulation times with no real-time capability. National dose rate data are provided to the European Commission (EC) via the EUropean Radiological Data Exchange Platform (EURDEP). In case of a nuclear emergency with transboundary implications, the EC may issue momentous recommendations to EU member states based on the radiological data collected by EURDEP. These recommendations may affect millions of people and could have severe economic and sociological consequences. Therefore, the reliability of the EURDEP data is of key importance. Unfortunately, the dose rate and activity concentration data are not harmonized between the different networks. Therefore, within the framework of the European Metrology Research Programme (EMRP), 16 European institutions formed the consortium MetroERM with the aim to improve the metrological foundation of measurements and to introduce a pan-European harmonization for the collation and evaluation of radiological data in early warning network systems. In addition, a new generation of detector systems based on spectrometers capable of providing both reliable dose rate values as well as nuclide specific information in real time are in development. The MetroERM project and its first results will be presented and discussed in this article.

  10. Optical frequency comb based multi-band microwave frequency conversion for satellite applications.

    Science.gov (United States)

    Yang, Xinwu; Xu, Kun; Yin, Jie; Dai, Yitang; Yin, Feifei; Li, Jianqiang; Lu, Hua; Liu, Tao; Ji, Yuefeng

    2014-01-13

    Based on optical frequency combs (OFC), we propose an efficient and flexible multi-band frequency conversion scheme for satellite repeater applications. The underlying principle is to mix dual coherent OFCs with one of which carrying the input signal. By optically channelizing the mixed OFCs, the converted signal in different bands can be obtained in different channels. Alternatively, the scheme can be configured to generate multi-band local oscillators (LO) for widely distribution. Moreover, the scheme realizes simultaneous inter- and intra-band frequency conversion just in a single structure and needs only three frequency-fixed microwave sources. We carry out a proof of concept experiment in which multiple LOs with 2 GHz, 10 GHz, 18 GHz, and 26 GHz are generated. A C-band signal of 6.1 GHz input to the proposed scheme is successfully converted to 4.1 GHz (C band), 3.9 GHz (C band) and 11.9 GHz (X band), etc. Compared with the back-to-back (B2B) case measured at 0 dBm input power, the proposed scheme shows a 9.3% error vector magnitude (EVM) degradation at each output channel. Furthermore, all channels satisfy the EVM limit in a very wide input power range.

  11. Curvelet Transform-Based Denoising Method for Doppler Frequency Extraction

    Institute of Scientific and Technical Information of China (English)

    HOU Shu-juan; WU Si-liang

    2007-01-01

    A novel image denoising method based on curvelet transform is proposed in order to improve the performance of Doppler frequency extraction in low signal-noise-ratio (SNR) environment. The echo can be represented as a gray image with spectral intensity as its gray values by time-frequency transform. And the curvelet coefficients of the image are computed. Then an adaptive soft-threshold scheme based on dual-median operation is implemented in curvelet domain. After that, the image is reconstructed by inverse curvelet transform and the Doppler curve is extracted by a curve detection scheme. Experimental results show the proposed method can improve the detection of Doppler frequency in low SNR environment.

  12. A frequency reconfigurable antenna based on digital microfluidics.

    Science.gov (United States)

    Damgaci, Yasin; Cetiner, Bedri A

    2013-08-07

    We present a novel antenna reconfiguration mechanism relying on electrowetting based digital microfluidics to implement a frequency reconfigurable antenna operating in the X-band. The antenna built on a quartz substrate (εr = 3.9, tan δ = 0.0002) is a coplanar waveguide fed annular slot antenna, which is monolithically integrated with a microfluidic chip. This chip establishes an electrowetting on dielectric platform with a mercury droplet placed in it. The base contact area of the mercury droplet can be spread out by electrostatic actuation resulting in a change of loading capacitance. This in turn changes the resonant frequency of the antenna enabling a reversible reconfigurable impedance property. This reconfigurable antenna has been designed, fabricated and measured. The frequency of operation is tuned from around 11 GHz to 13 GHz as demonstrated by simulations and measurements. The design methodology, fabrication processes and the experimental results are given and discussed.

  13. A frequency based constraint for a multi-frequency linear sampling method

    Science.gov (United States)

    Alqadah, H. F.; Valdivia, N.

    2013-09-01

    The linear sampling method (LSM) has become a well established non-iterative technique for a variety of inverse scattering problems. The method offers a number of advantages over competing inverse scattering methods, mainly it is based on solving a linear problem while being able to account for multi-path effects. Unfortunately under the current framework the method is only effective when using a large number of multi-static data, and therefore may be impractical for many imaging applications. While primarily developed under a single frequency framework, recently the extension of the method to multi-banded data sets has been considered. It is known in general that the availability of multi-frequency data should compensate for reduced spatial diversity, but it is not clear how this can be accomplished for the LSM. In this work we take a step in this direction by considering a frequency based partial variation approach. We first establish that on bands absent of any corresponding Dirichlet eigenvalues the Herglotz density exhibits bounded variation. We then consider a regularization method incorporating this prior knowledge. The proposed approach exhibited a good estimate of the unknown Dirichlet eigenvalues of the obstacle in question when using reduced data. This observation also correlated with higher quality 3D reconstructions.

  14. Modeling Frequency Comb Sources

    Directory of Open Access Journals (Sweden)

    Li Feng

    2016-06-01

    Full Text Available Frequency comb sources have revolutionized metrology and spectroscopy and found applications in many fields. Stable, low-cost, high-quality frequency comb sources are important to these applications. Modeling of the frequency comb sources will help the understanding of the operation mechanism and optimization of the design of such sources. In this paper,we review the theoretical models used and recent progress of the modeling of frequency comb sources.

  15. Metrological Analysis on Literature in Chinese Agricultural Science Field Based on ESI Database%基于ESI数据库中国农业科学领域文献计量分析研究

    Institute of Scientific and Technical Information of China (English)

    梁花侠; 白君礼

    2013-01-01

    Based on United States ESI literature metrological analysis database, the paper metro logically analyzes the global agricultural and China agricultural science literatures in ten years from 2001 to 2011.By analysising the indicators, such as countries and regions, research institutions, journals, scientists, high cited papers, hot papers, the top articles, research frontier, the baseline and etc, the paper is thought to be able to provide important refrence for our country agricultural scientific research.%利用美国ESI文献计量分析数据库对2001年~ 2011年10年来全球农业科学领域和中国农业科学领域的文献进行了计量分析.通过对国家和地区、研究机构、期刊、科学家、高被引论文、热点论文、顶级论文、研究前沿、基线等各项指标统计分析,为我国农业科学研究提供重要参考.

  16. Developments in remote metrology at JET

    Energy Technology Data Exchange (ETDEWEB)

    Mindham, T.J., E-mail: tim.mindham@ccfe.ac.uk [JET-EFDA, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); CCFE, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Sandford, G.C.; Hermon, G. [JET-EFDA, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); CCFE, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Belcher, C. [JET-EFDA, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Oxford Technologies Ltd., 7 Nuffield Way, Abingdon, OX14 1RJ (United Kingdom); CCFE, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Pace, N. [JET-EFDA, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Babcock Nuclear Division, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); CCFE, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom)

    2011-10-15

    The need to maximise the operational availability of fusion devices has driven the enhancements in accuracy, flexibility and speed associated with the inspection techniques used at JET. To this end, the remote installation of the ITER-Like Wall (ILW) tiles, conduits and embedded diagnostics has necessitated the adoption of technologies from other industries for their use in conjunction with the JET Remote Handling (RH) system. The novel adaptation of targetless stereophotogrammetry, targeted single-camera photogrammetry and gap measurement techniques for remote applications has prompted a range of challenges and lessons learnt both from the design process and operational experience. Interfacing Commercial Off-The-Shelf (COTS) components with the existing RH equipment has highlighted several issues of relevance to the developing ITER RH system. This paper reports results from the stereophotogrammetry and the single-camera photogrammetry surveys, allowing analysis of the effectiveness of the RH system as a platform for in-vessel measurement. This includes scrutiny of the accuracy achieved with each technique as well as the impact on the in-vessel Configuration Management Model (CMM). The paper concludes with a summary of key recommendations for the ITER RH system based on the experience of remote metrology at JET.

  17. Mueller matrix imaging ellipsometry for nanostructure metrology.

    Science.gov (United States)

    Liu, Shiyuan; Du, Weichao; Chen, Xiuguo; Jiang, Hao; Zhang, Chuanwei

    2015-06-29

    In order to achieve effective process control, fast, inexpensive, nondestructive and reliable nanometer scale feature measurements are extremely useful in high-volume nanomanufacturing. Among the possible techniques, optical scatterometry is relatively ideal due to its high throughput, low cost, and minimal sample damage. However, this technique is inherently limited by the illumination spot size of the instrument and the low efficiency in construction of a map of the sample over a wide area. Aiming at these issues, we introduce conventional imaging techniques to optical scatterometry and combine them with Mueller matrix ellipsometry based scatterometry, which is expected to be a powerful tool for the measurement of nanostructures in future high-volume nanomanufacturing, and propose to apply Mueller matrix imaging ellipsometry (MMIE) for nanostructure metrology. Two kinds of nanostructures were measured using an in-house developed Mueller matrix imaging ellipsometer in this work. The experimental results demonstrate that we can achieve Mueller matrix measurement and analysis for nanostructures with pixel-sized illumination spots by using MMIE. We can also efficiently construct parameter maps of the nanostructures over a wide area with pixel-sized lateral resolution by performing parallel ellipsometric analysis for all the pixels of interest.

  18. Distributed large-scale dimensional metrology new insights

    CERN Document Server

    Franceschini, Fiorenzo; Maisano, Domenico

    2011-01-01

    Focuses on the latest insights into and challenges of distributed large scale dimensional metrology Enables practitioners to study distributed large scale dimensional metrology independently Includes specific examples of the development of new system prototypes

  19. Joint Research on Scatterometry and AFM Wafer Metrology

    NARCIS (Netherlands)

    Bodermann, B.; Buhr, E.; Danzebrink, H.U.; Bär, M.; Scholze, F.; Krumrey, M.; Wurm, M.; Klapetek, P.; Hansen, P.E.; Korpelainen, V.; Van Veghel, M.; Yacoot, A.; Siitonen, S.; El Gawhary, O.; Burger, S.; Saastamoinen, T.

    2011-01-01

    Supported by the European Commission and EURAMET, a consortium of 10 participants from national metrology institutes, universities and companies has started a joint research project with the aim of overcoming current challenges in optical scatterometry for traceable linewidth metrology. Both

  20. Research on English vocabulary teaching based on frequency

    Directory of Open Access Journals (Sweden)

    Ying Shi

    2017-02-01

    Full Text Available The key to accurately grasp the semantics in the context is to grasp the vocabularies. Only mastering a lot of vocabularies, many methods will be available in the process of English vocabulary learning and memory, of which English vocabulary teaching based on frequency gradually becomes an English vocabulary learning method recognized by everyone. In English teaching process, this paper makes the current English learning form a more systematic and comprehensive context theory through the questionnaires and application for English context and frequency method in English teaching process, thus proposing a feasible teaching method for the overall grasp of English language.

  1. Construction of Frequency Hopping Sequence Set Based upon Generalized Cyclotomy

    CERN Document Server

    Liu, Fang; Zhou, Zhengchun; Tang, Xiaohu

    2010-01-01

    Frequency hopping (FH) sequences play a key role in frequency hopping spread spectrum communication systems. It is important to find FH sequences which have simultaneously good Hamming correlation, large family size and large period. In this paper, a new set of FH sequences with large period is proposed, and the Hamming correlation distribution of the new set is investigated. The construction of new FH sequences is based upon Whiteman's generalized cyclotomy. It is shown that the proposed FH sequence set is optimal with respect to the average Hamming correlation bound.

  2. Accurate in-line CD metrology for nanometer semiconductor manufacturing

    Science.gov (United States)

    Perng, Baw-Ching; Shieh, Jyu-Horng; Jang, S.-M.; Liang, M.-S.; Huang, Renee; Chen, Li-Chien; Hwang, Ruey-Lian; Hsu, Joe; Fong, David

    2006-03-01

    The need for absolute accuracy is increasing as semiconductor-manufacturing technologies advance to sub-65nm nodes, since device sizes are reducing to sub-50nm but offsets ranging from 5nm to 20nm are often encountered. While TEM is well-recognized as the most accurate CD metrology, direct comparison between the TEM data and in-line CD data might be misleading sometimes due to different statistical sampling and interferences from sidewall roughness. In this work we explore the capability of CD-AFM as an accurate in-line CD reference metrology. Being a member of scanning profiling metrology, CD-AFM has the advantages of avoiding e-beam damage and minimum sample damage induced CD changes, in addition to the capability of more statistical sampling than typical cross section metrologies. While AFM has already gained its reputation on the accuracy of depth measurement, not much data was reported on the accuracy of CD-AFM for CD measurement. Our main focus here is to prove the accuracy of CD-AFM and show its measuring capability for semiconductor related materials and patterns. In addition to the typical precision check, we spent an intensive effort on examining the bias performance of this CD metrology, which is defined as the difference between CD-AFM data and the best-known CD value of the prepared samples. We first examine line edge roughness (LER) behavior for line patterns of various materials, including polysilicon, photoresist, and a porous low k material. Based on the LER characteristics of each patterning, a method is proposed to reduce its influence on CD measurement. Application of our method to a VLSI nanoCD standard is then performed, and agreement of less than 1nm bias is achieved between the CD-AFM data and the standard's value. With very careful sample preparations and TEM tool calibration, we also obtained excellent correlation between CD-AFM and TEM for poly-CDs ranging from 70nm to 400nm. CD measurements of poly ADI and low k trenches are also

  3. Advances in Solar Radiometry and Metrology

    Energy Technology Data Exchange (ETDEWEB)

    Myers, D.; Andreas, A.; Reda, I.; Gotseff, P.; Wilcox, S.; Stoffel, T.; Anderberg, M.

    2005-01-01

    The Solar Radiometry and Metrology task at the National Renewable Energy Laboratory (NREL) provides traceable optical radiometric calibrations and measurements to photovoltaic (PV) researchers and the PV industry. Traceability of NREL solar radiometer calibrations to the World Radiometric Reference (WRR) was accomplished during the NREL Pyrheliometer Comparison in October 2003. The task has calibrated 10 spectral and more than 180 broadband radiometers for solar measurements. Other accomplishments include characterization of pyranometer thermal offset errors with laboratory and spectral modeling tools; developing a simple scheme to correct pyranometer data for known responsivity variations; and measuring detailed spectral distributions of the NREL High Intensity Pulsed Solar Simulator (HIPSS) as a function of lamp voltage and time. The optical metrology functions support the NREL Measurement and Characterization Task effort for ISO 17025 accreditation of NREL Solar Reference Cell Calibrations. Optical metrology functions have been integrated into the NREL quality system and audited for ISO17025 compliance.

  4. Metrology and properties of engineering surfaces

    CERN Document Server

    Greenwood, J; Chetwynd, D

    2001-01-01

    Metrology and Properties of Engineering Surfaces provides in a single volume a comprehensive and authoritative treatment of the crucial topics involved in the metrology and properties of engineering surfaces. The subject matter is a central issue in manufacturing technology, since the quality and reliability of manufactured components depend greatly upon the selection and qualities of the appropriate materials as ascertained through measurement. The book can in broad terms be split into two parts; the first deals with the metrology of engineering surfaces and covers the important issues relating to the measurement and characterization of surfaces in both two and three dimensions. This covers topics such as filtering, power spectral densities, autocorrelation functions and the use of Fractals in topography. A significant proportion is dedicated to the calibration of scanning probe microscopes using the latest techniques. The remainder of the book deals with the properties of engineering surfaces and covers a w...

  5. Circularly split-ring-resonator-based frequency-reconfigurable antenna

    Science.gov (United States)

    Rahman, M. A.; Faruque, M. R. I.; Islam, M. T.

    2017-01-01

    In this paper, an antenna with frequency configurability in light of a circularly split-ring resonator (CSRR) is introduced. The proposed reconfigurable monopole antenna consists of a microstrip-fed hook-shaped structure and a CSRR having single reconfigurable split only. A new band of radiation unlike the band radiated from monopole only is observed due to magnetic coupling between the CSRR and the monopole antenna. The resonance frequency of the CSRR can be arbitrarily chosen by varying the dimension and relative position of its gap with the monopole, which leads the antenna to become reconfigurable one. By using a single switch with perfect electric conductor at the gap of CSRR cell, the effect of CSRR can be deactivated and, hence, it is possible to suppress the corresponding resonance, resulting in a frequency-reconfigurable antenna. Commercially available Computer Simulation Technology microwave studio based on finite integration technique was adopted throughout the study.

  6. Time-frequency representation measurement based on temporal Fourier transformation

    Science.gov (United States)

    Suen, Yifan; Xiao, Shaoqiu; Hao, Sumin; Zhao, Xiaoxiang; Xiong, Yigao; Liu, Shenye

    2016-10-01

    We propose a new scheme to physically realize the short-time Fourier transform (STFT) of chirped optical pulse using time-lens array that enables us to get time-frequency representation without using FFT algorithm. The time-lens based upon the four-wave mixing is used to perform the process of temporal Fourier transformation. Pump pulse is used for both providing the quadratic phase and being the window function of STFT. The idea of STFT is physically realized in our scheme. Simulations have been done to investigate performance of the time-frequency representation scheme (TFRS) in comparison with STFT using FFT algorithm. Optimal measurement of resolution in time and frequency has been discussed.

  7. Portable atomic frequency standard based on coherent population trapping

    Science.gov (United States)

    Shi, Fan; Yang, Renfu; Nian, Feng; Zhang, Zhenwei; Cui, Yongshun; Zhao, Huan; Wang, Nuanrang; Feng, Keming

    2015-05-01

    In this work, a portable atomic frequency standard based on coherent population trapping is designed and demonstrated. To achieve a portable prototype, in the system, a single transverse mode 795nm VCSEL modulated by a 3.4GHz RF source is used as a pump laser which generates coherent light fields. The pump beams pass through a vapor cell containing atom gas and buffer gas. This vapor cell is surrounded by a magnetic shield and placed inside a solenoid which applies a longitudinal magnetic field to lift the Zeeman energy levels' degeneracy and to separate the resonance signal, which has no first-order magnetic field dependence, from the field-dependent resonances. The electrical control system comprises two control loops. The first one locks the laser wavelength to the minimum of the absorption spectrum; the second one locks the modulation frequency and output standard frequency. Furthermore, we designed the micro physical package and realized the locking of a coherent population trapping atomic frequency standard portable prototype successfully. The short-term frequency stability of the whole system is measured to be 6×10-11 for averaging times of 1s, and reaches 5×10-12 at an averaging time of 1000s.

  8. Mask Design for the Space Interferometry Mission Internal Metrology

    Science.gov (United States)

    Marx, David; Zhao, Feng; Korechoff, Robert

    2005-01-01

    This slide presentation reviews the mask design used for the internal metrology of the Space Interferometry Mission (SIM). Included is information about the project, the method of measurements with SIM, the internal metrology, numerical model of internal metrology, wavefront examples, performance metrics, and mask design

  9. The optimization of super-high resolution frequency measurement techniques based on phase quantization regularities between any frequencies.

    Science.gov (United States)

    Li, Zhiqi; Zhou, Wei; Zhou, Hui; Zhang, Xueping; Zhao, Jie

    2013-02-01

    Step phase quantization regularity between different nominal frequency signals is introduced in this paper. Based on this regularity, an optimized high resolution frequency measurement technique is presented. The key features and issues of phase quantization characteristics and measurements are described. Based on the relationship between the same or multiple nominal signals with a certain differences, the resolution of frequency measurements is developed and the range is widened. Several measurement results are provided to support the concepts with experimental evidence. The resolution of frequency measurement can reach 10(-12) (s(-1)) over a wide range or higher for specific frequency signals.

  10. Noninvasive spatial metrology of single-atom devices.

    Science.gov (United States)

    Mohiyaddin, Fahd A; Rahman, Rajib; Kalra, Rachpon; Klimeck, Gerhard; Hollenberg, Lloyd C L; Pla, Jarryd J; Dzurak, Andrew S; Morello, Andrea

    2013-05-01

    The exact location of a single dopant atom in a nanostructure can influence or fully determine the functionality of highly scaled transistors or spin-based devices. We demonstrate here a noninvasive spatial metrology technique, based on the microscopic modeling of three electrical measurements on a single-atom (phosphorus in silicon) spin qubit device: hyperfine coupling, ground state energy, and capacitive coupling to nearby gates. This technique allows us to locate the qubit atom with a precision of ±2.5 nm in two directions and ±15 nm in the third direction, which represents a 1500-fold improvement with respect to the prefabrication statistics obtainable from the ion implantation parameters.

  11. Coordinate Metrology by Traceable Computed Tomography

    DEFF Research Database (Denmark)

    Müller, Pavel

    metrology and coordinate metrology and is currently becoming more and more important measuring technique for dimensional measurements. This is mainly due to the fact that with CT, a complete three-dimensional model of the scanned part is in a relatively short time visualized using a computer...... is an important factor for decision making about manufactured parts. However, due to many influences in CT, estimation of the uncertainty is a challenge, also because standardized procedures and guidelines are not available yet. In this thesis, several methods for uncertainty estimation were applied in connection...

  12. Semiconductor strain metrology principles and applications

    CERN Document Server

    Wong, Terence KS

    2012-01-01

    This book surveys the major and newly developed techniques for semiconductor strain metrology. Semiconductor strain metrology has emerged in recent years as a topic of great interest to researchers involved in thin film and nanoscale device characterization. This e-book employs a tutorial approach to explain the principles and applications of each technique specifically tailored for graduate students and postdoctoral researchers. Selected topics include optical, electron beam, ion beam and synchrotron x-ray techniques. Unlike earlier references, this e-book specifically discusses strain metrol

  13. Vacuum Technology Considerations For Mass Metrology

    Science.gov (United States)

    Abbott, Patrick J.; Jabour, Zeina J.

    2011-01-01

    Vacuum weighing of mass artifacts eliminates the necessity of air buoyancy correction and its contribution to the measurement uncertainty. Vacuum weighing is also an important process in the experiments currently underway for the redefinition of the SI mass unit, the kilogram. Creating the optimum vacuum environment for mass metrology requires careful design and selection of construction materials, plumbing components, pumping, and pressure gauging technologies. We review the vacuum technology1 required for mass metrology and suggest procedures and hardware for successful and reproducible operation. PMID:26989593

  14. Using entanglement against noise in quantum metrology.

    Science.gov (United States)

    Demkowicz-Dobrzański, Rafal; Maccone, Lorenzo

    2014-12-19

    We analyze the role of entanglement among probes and with external ancillas in quantum metrology. In the absence of noise, it is known that unentangled sequential strategies can achieve the same Heisenberg scaling of entangled strategies and that external ancillas are useless. This changes in the presence of noise; here we prove that entangled strategies can have higher precision than unentangled ones and that the addition of passive external ancillas can also increase the precision. We analyze some specific noise models and use the results to conjecture a general hierarchy for quantum metrology strategies in the presence of noise.

  15. Single shot interferogram analysis for optical metrology.

    Science.gov (United States)

    Singh, Mahendra Pratap; Singh, Mandeep; Khare, Kedar

    2014-10-10

    We report a novel constrained optimization method for single shot interferogram analysis. The unknown test wavefront is estimated as a minimum L2-norm squared solution whose phase is constrained to the space spanned by a finite number of Zernike polynomials. Using a single frame from standard phase shifting datasets, we demonstrate that our approach provides a phase map that matches with that generated using phase shifting algorithms to within λ/100  rms error. Our simulations and experimental results suggest the possibility of a simplified low-cost high quality optical metrology system for performing routine metrology tests involving smooth surface profiles.

  16. Three-dimensional metrology for printed electronics

    Science.gov (United States)

    Bromberg, Vadim; Harding, Kevin

    2017-05-01

    Novel materials and printing technologies can enable rapid and low cost prototyping and manufacturing of electronic devices with increased flexibility and complexity. However, robust and on-demand printing of circuits will require accurate metrology methods that can measure micron level patterns to verify proper production. This paper presents an evaluation of a range of optical gaging tools ranging from confocal to area 3D systems to determine metrological capability for a range of key parameters from trace thickness to solder paste volumes. Finally, this paper will present a select set of optimized measurement tools detailing both capabilities and gaps in the available technologies needed to fully realize the potential of printed electronics.

  17. Structural eigenfrequency optimization based on local sub-domain "frequencies"

    DEFF Research Database (Denmark)

    Pedersen, Pauli; Pedersen, Niels Leergaard

    2013-01-01

    The engineering approach of fully stressed design is a practical tool with a theoretical foundation. The analog approach to structural eigenfrequency optimization is presented here with its theoretical foundation. A numerical redesign procedure is proposed and illustrated with examples.......For the ideal case, an optimality criterion is fulfilled if the design have the same sub-domain ”frequency” (local Rayleigh quotient). Sensitivity analysis shows an important relation between squared system eigenfrequency and squared local sub-domain frequency for a given eigenmode. Higher order...... eigenfrequencies may also be controlled in this manner.The presented examples are based on 2D finite element models with the use of subspace iteration for analysis and a recursive design procedure based on the derived optimality condition. The design that maximize a frequency depend on the total amount...

  18. Photonic radio-frequency phase shifter based on polarization interference.

    Science.gov (United States)

    Chen, Han; Dong, Yi; He, Hao; Hu, Weisheng; Li, Lemin

    2009-08-01

    An rf photonic phase shifter based on polarization interference is presented, and the theoretical fundamentals of the design are explained. This phase shifter provides broad operational bandwidth and a full 360 degrees phase-shift tuning range with a single external electrical control. A prototype of the rf photonic phase shifter with a frequency of 26.75 GHz and 360 degrees tuning range is experimentally demonstrated.

  19. Estimating High-Frequency Based (Co-) Variances: A Unified Approach

    DEFF Research Database (Denmark)

    Voev, Valeri; Nolte, Ingmar

    We propose a unified framework for estimating integrated variances and covariances based on simple OLS regressions, allowing for a general market microstructure noise specification. We show that our estimators can outperform, in terms of the root mean squared error criterion, the most recent...... frequency derived in Bandi & Russell (2005a) and Bandi & Russell (2005b). For a realistic trading scenario, the efficiency gains resulting from our approach are in the range of 35% to 50%....

  20. A Single Pattern Matching Algorithm Based on Character Frequency

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Based on the study of single pattern matching, MBF algorithm is proposed by imitating the string searching procedure of human. The algorithm preprocesses the pattern by using the idea of Quick Search algorithm and the already-matched pattern psefix and suffix information. In searching phase, the algorithm makes use of the!character using frequency and the continue-skip idea. The experiment shows that MBF algorithm is more efficient than other algorithms.

  1. Identification of damage based on frequency response function (FRF data

    Directory of Open Access Journals (Sweden)

    Sulaiman M. S. A.

    2017-01-01

    Full Text Available Mechanical joints, particularly fasteners such as bolted joints have a complex non-linear behaviour. The non-linearity might emerge from the material, geometry or by the contacts in the joints. However, damage to a structure can be happened either their connections or the material of components. The effect of damage can change the dynamic properties of the structure such as natural frequencies and mode shapes and structural performance and can cause premature failure to structure. This paper presents a damage detection method using a vibration based damage detection method based on the frequency response function (FRF data. A combination of numerical model and physical bolted jointed structure of damaged and undamaged structure will be investigated. The validation is employed to detect the presence of damage in the structure based on the frequency response function (FRF data from the parameter values used in the benchmark model and damaged model. The comparisons of the undamaged and damaged structure of the FRF have revealed the damaged structure was shifted from the undamaged structure. The effect of the FRF between undamaged and damaged structure is clearly affected by the reduction of stiffness for the damaged structure.

  2. Electrical test prediction using hybrid metrology and machine learning

    Science.gov (United States)

    Breton, Mary; Chao, Robin; Muthinti, Gangadhara Raja; de la Peña, Abraham A.; Simon, Jacques; Cepler, Aron J.; Sendelbach, Matthew; Gaudiello, John; Emans, Susan; Shifrin, Michael; Etzioni, Yoav; Urenski, Ronen; Lee, Wei Ti

    2017-03-01

    Electrical test measurement in the back-end of line (BEOL) is crucial for wafer and die sorting as well as comparing intended process splits. Any in-line, nondestructive technique in the process flow to accurately predict these measurements can significantly improve mean-time-to-detect (MTTD) of defects and improve cycle times for yield and process learning. Measuring after BEOL metallization is commonly done for process control and learning, particularly with scatterometry (also called OCD (Optical Critical Dimension)), which can solve for multiple profile parameters such as metal line height or sidewall angle and does so within patterned regions. This gives scatterometry an advantage over inline microscopy-based techniques, which provide top-down information, since such techniques can be insensitive to sidewall variations hidden under the metal fill of the trench. But when faced with correlation to electrical test measurements that are specific to the BEOL processing, both techniques face the additional challenge of sampling. Microscopy-based techniques are sampling-limited by their small probe size, while scatterometry is traditionally limited (for microprocessors) to scribe targets that mimic device ground rules but are not necessarily designed to be electrically testable. A solution to this sampling challenge lies in a fast reference-based machine learning capability that allows for OCD measurement directly of the electrically-testable structures, even when they are not OCD-compatible. By incorporating such direct OCD measurements, correlation to, and therefore prediction of, resistance of BEOL electrical test structures is significantly improved. Improvements in prediction capability for multiple types of in-die electrically-testable device structures is demonstrated. To further improve the quality of the prediction of the electrical resistance measurements, hybrid metrology using the OCD measurements as well as X-ray metrology (XRF) is used. Hybrid metrology

  3. Absolute distance metrology for space interferometers

    NARCIS (Netherlands)

    Swinkels, B.L.; Latoui, A.; Bhattacharya, N.; Wielders, A.A.; Braat, J.J.M.

    2005-01-01

    Future space missions, among which the Darwin Space Interferometer, will consist of several free flying satellites. A complex metrology system is required to have all the components fly accurately in formation and have it operate as a single instrument. Our work focuses on a possible implementation

  4. Traceability and uncertainty estimation in coordinate metrology

    DEFF Research Database (Denmark)

    Hansen, Hans Nørgaard; Savio, Enrico; De Chiffre, Leonardo

    2001-01-01

    are required. Depending on the requirements for uncertainty level, different approaches may be adopted to achieve traceability. Especially in the case of complex measurement situations and workpieces the procedures are not trivial. This paper discusses the establishment of traceability in coordinate metrology...

  5. [Metrological software of laser medical equipment].

    Science.gov (United States)

    Romashkov, A P; Glazov, A I; Tikhomirov, S V

    2001-01-01

    The paper considers the laser medical equipment situation that has established in Russia and that is characterized by the wide medical application of laser technologies and appropriate software and by inadequate development and imperfection of required metrological software and maintenance of laser equipment.

  6. Novel Frequency Hopping Sequences Generator Based on AES Algorithm

    Institute of Scientific and Technical Information of China (English)

    李振荣; 庄奕琪; 张博; 张超

    2010-01-01

    A novel frequency hopping(FH) sequences generator based on advanced encryption standard(AES) iterated block cipher is proposed for FH communication systems.The analysis shows that the FH sequences based on AES algorithm have good performance in uniformity, correlation, complexity and security.A high-speed, low-power and low-cost ASIC of FH sequences generator is implemented by optimizing the structure of S-Box and MixColumns of AES algorithm, proposing a hierarchical power management strategy, and applying ...

  7. Natural frequencies and damping estimation based on continuous wavelet transform

    Institute of Scientific and Technical Information of China (English)

    DAI Yu; SUN He-yi; LI Hui-peng; TANG Wen-yan

    2008-01-01

    The continuous wavelet transform (CWT) based method was improved for estimating the natural fre-quencies and damping ratios of a structural system in this paper. The appropriate scale of CWT was selected by means of the least squares method to identify the systems with closely spaced modes. The important issues relat-ed to estimation accuracy such as mode separation and end effect, were also investigated. These issues were as-sociated with the parameter selection of wavelet function based on the fitting error of least squares. The efficien-cy of the method was confirmed by applying it to a simulated 3dof damped system with two close modes.

  8. Laser metrology in fluid mechanics granulometry, temperature and concentration measurements

    CERN Document Server

    Boutier, Alain

    2013-01-01

    In fluid mechanics, non-intrusive measurements are fundamental in order to improve knowledge of the behavior and main physical phenomena of flows in order to further validate codes.The principles and characteristics of the different techniques available in laser metrology are described in detail in this book.Velocity, temperature and concentration measurements by spectroscopic techniques based on light scattered by molecules are achieved by different techniques: laser-induced fluorescence, coherent anti-Stokes Raman scattering using lasers and parametric sources, and absorption sp

  9. Metrology system for the Terrestrial Planet Finder Coronagraph

    Science.gov (United States)

    Shaklin, Stuart; Marchen, Luis; Zhao, Feng; Peters, Robert D.; Ho, Tim; Holmes, Buck

    2004-01-01

    The Terrestrial Planet Finder (TPF) employs an aggressive coronagraph designed to obtain better than 1e-10 contrast inside the third Airy ring. Minute changes in low-order aberration content scatter significant light at this position. One implication is the requirement to control low-order aberrations induced by motion of the secondary mirror relative to the primary mirror; sub-nanometer relative positional stability is required. We propose a 6-beam laser truss to monitor the relative positions of the two mirrors. The truss is based on laser metrology developed for the Space Interferometry Mission.

  10. Calibration of space instruments at the Metrology Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Klein, R., E-mail: roman.klein@ptb.de; Fliegauf, R.; Gottwald, A.; Kolbe, M.; Paustian, W.; Reichel, T.; Richter, M.; Thornagel, R.; Ulm, G. [Physikalisch-Technische Bundesanstalt (PTB), Berlin (Germany)

    2016-07-27

    PTB has more than 20 years of experience in the calibration of space-based instruments using synchrotron radiation to cover the UV, VUV and X-ray spectral range. New instrumentation at the electron storage ring Metrology Light Source (MLS) opens up extended calibration possibilities within this framework. In particular, the set-up of a large vacuum vessel that can accommodate entire space instruments opens up new prospects. Moreover, a new facility for the calibration of radiation transfer source standards with a considerably extended spectral range has been put into operation. Besides, characterization and calibration of single components like e.g. mirrors, filters, gratings, and detectors is continued.

  11. A physically based analytical model of flood frequency curves

    Science.gov (United States)

    Basso, S.; Schirmer, M.; Botter, G.

    2016-09-01

    Predicting magnitude and frequency of floods is a key issue in hydrology, with implications in many fields ranging from river science and geomorphology to the insurance industry. In this paper, a novel physically based approach is proposed to estimate the recurrence intervals of seasonal flow maxima. The method links the extremal distribution of streamflows to the stochastic dynamics of daily discharge, providing an analytical expression of the seasonal flood frequency curve. The parameters involved in the formulation embody climate and landscape attributes of the contributing catchment and can be estimated from daily rainfall and streamflow data. Only one parameter, which is linked to the antecedent wetness condition in the watershed, needs to be calibrated on the observed maxima. The performance of the method is discussed through a set of applications in four rivers featuring heterogeneous daily flow regimes. The model provides reliable estimates of seasonal maximum flows in different climatic settings and is able to capture diverse shapes of flood frequency curves emerging in erratic and persistent flow regimes. The proposed method exploits experimental information on the full range of discharges experienced by rivers. As a consequence, model performances do not deteriorate when the magnitude of events with return times longer than the available sample size is estimated. The approach provides a framework for the prediction of floods based on short data series of rainfall and daily streamflows that may be especially valuable in data scarce regions of the world.

  12. Smart Cylindrical Dome Antenna Based on Active Frequency Selective Surface

    Directory of Open Access Journals (Sweden)

    Tongyu Ding

    2017-01-01

    Full Text Available In this paper, we proposed a beamforming antenna, which is realized using an omnidirectional antenna in the center surrounded by a cylindrical smart dome. The smart dome is made of 16 active frequency selective surface columns of which the amplitude and phase response can be continuously tuned by varying the bias voltages of the employed varactors. Thus, the performance of the proposed antenna could achieve higher gain, better nulling level, and more agility than many switch methods-based cylindrical reconfigurable antennas. Moreover, in order to overcome the unavailable analytical synthesis caused by complex mutual coupling between columns, we develop a genetic algorithm based optimization system and conducted a serial of experiments to evaluate the high-gain, nulling, continuously steering, and frequency-invariant ability. The results show that, during the frequency tunable range of the AFSS (2.0 GHz to 2.7 GHz, the antenna can offer an additional gain of up to 6.57 dB and nulling level of −56.41 dBi. For the high-gain modes, the −3 dB beam widths are 26°–34°, which offers enhanced angular resolution compared with other reported beam-sweeping work. Furthermore, the radiation pattern is continuously steerable.

  13. Coupling of relative intensity noise and pathlength noise to the length measurement in the optical metrology system of LISA Pathfinder

    Science.gov (United States)

    Wittchen, Andreas; the LPF Collaboration

    2017-05-01

    LISA Pathfinder is a technology demonstration mission for the space-based gravitational wave observatory, LISA. It demonstrated that the performance requirements for the interferometric measurement of two test masses in free fall can be met. An important part of the data analysis is to identify the limiting noise sources. [1] This measurement is performed with heterodyne interferometry. The performance of this optical metrology system (OMS) at high frequencies is limited by sensing noise. One such noise source is Relative Intensity Noise (RIN). RIN is a property of the laser, and the photodiode current generated by the interferometer signal contains frequency dependant RIN. From this electric signal the phasemeter calculates the phase change and laser power, and the coupling of RIN into the measurement signal depends on the noise frequency. RIN at DC, at the heterodyne frequency and at two times the heterodyne frequency couples into the phase. Another important noise at high frequencies is path length noise. To reduce the impact this noise is suppressed with a control loop. Path length noise not suppressed will couple directly into the length measurement. The subtraction techniques of both noise sources depend on the phase difference between the reference signal and the measurement signal, and thus on the test mass position. During normal operations we position the test mass at the interferometric zero, which is optimal for noise subtraction purposes. This paper will show results from an in-flight experiment where the test mass position was changed to make the position dependant noise visible.

  14. Requirements of weighing in legal metrology

    Science.gov (United States)

    Källgren, Håkan; Pendrill, Leslie

    2003-12-01

    A review is given of recent developments in the formulation of requirements of weighing where such measurements are performed in society and industry with legal implications such as safety, fair trade and environmental considerations. Traditional legal metrology in the area of weights and measures has been developed and given an expanded scope in recent years. This reflects, on the one hand, technical and scientific development (computerization of weighing devices, improved weight manufacturing and new methods of magnetism determination, for example), and on the other hand, administrative evolution (global requirements of the market and the Measurement Instrument Directive). Particularly fruitful has been the joint effort by the scientific mass metrology and legal metrology communities in the development in the last decade of international recommendations—especially OIML R111—on weighing. Consensus has been reached in the international weighing forum concerning important areas such as maximum permissible errors for weights, how to calculate measurement uncertainty and how measurement uncertainty should be accounted for in relation to conformity assessment. These international recommendations for weights as mass standards include both tolerances and extensive instructions about various influence quantities that affect the weight result, such as magnetization, surface roughness and volume of weights. Much remains to be done, however: corresponding requirements of weighing devices in particular need to meet the challenges of a rapidly changing technology. The promising collaboration between scientific and legal metrology initiated in the area of weights may act as a model and stimulate similar developments in other areas of metrology, particularly where requirements are generic (for instance uncertainty and conformity) or analogous.

  15. Intermediate Frequency Digital Receiver Based on Multi-FPGA System

    Directory of Open Access Journals (Sweden)

    Chengchang Zhang

    2016-01-01

    Full Text Available Aiming at high-cost, large-size, and inflexibility problems of traditional analog intermediate frequency receiver in the aerospace telemetry, tracking, and command (TTC system, we have proposed a new intermediate frequency (IF digital receiver based on Multi-FPGA system in this paper. Digital beam forming (DBF is realized by coordinated rotation digital computer (CORDIC algorithm. An experimental prototype has been developed on a compact Multi-FPGA system with three FPGAs to receive 16 channels of IF digital signals. Our experimental results show that our proposed scheme is able to provide a great convenience for the design of IF digital receiver, which offers a valuable reference for real-time, low power, high density, and small size receiver design.

  16. Decay ratio estimation based on time-frequency representations

    Energy Technology Data Exchange (ETDEWEB)

    Torres-Fernandez, Jose E.; Prieto-Guerrero, Alfonso [Division de Ciencias Basicas e Ingenieria, Universidad Autonoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, Mexico D.F. 09340 (Mexico); Espinosa-Paredes, Gilberto, E-mail: gepe@xanum.uam.m [Division de Ciencias Basicas e Ingenieria, Universidad Autonoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, Mexico D.F. 09340 (Mexico)

    2010-02-15

    A novel method based on bilinear time-frequency representations (TFRs) is proposed to determine the time evolution of the linear stability parameters of a boiling water reactor (BWR) using neutronic noise signals. TFRs allow us to track the instantaneous frequencies contained in a signal to estimate an instantaneous decay ratio (IDR) that closely follows the signal envelope changes in time, making the IDR a measure of local stability. In order to account for long term changes in BWR stability, the ACDR measure is introduced as the accumulated product of the local IDRs. As it is shown in this paper, the ACDR measure clearly reflects major long term changes in BWR stability. Last to validate our method, synthetic and real neutronic signals were used. The methodology was tested on the Laguna Verde Unit 1, two events were reported in the Forsmark stability benchmark.

  17. Subsea acoustic metrology of jumper&spool based on EKF-SLAM algorithm%基于EKF-SLAM算法的水下膨胀弯测量技术

    Institute of Scientific and Technical Information of China (English)

    隋海琛; 王崇明; 雷鹏

    2015-01-01

    Subsea metrology surveys are conducted to determine accurately the relative horizontal and vertical distance between subsea assets, as well as their relative heading and attitude. This information is then used by pipe-line engineers to design connection pieces to join the assets together. Based on acoustic measurement technology and the fusion of acoustic positioning, inertial navigation, Doppler velocity log, pressure gauge, sound velocity meter data under water, the EKF-SLAM algorithm was described in this paper. It can realize the cm level accuracy, and operating mode is simple, no depth and visibility constraints. It can effectively improve the work efficiency to save the time and cost.%水下计量技术普遍应用于海管法兰之间相对空间位置和方位角的测量,其结果直接关系到水下膨胀弯的设计和预制是否准确.文章阐述了基于EKF-SLAM算法,融合水下声学定位、惯性导航、多普勒计程仪、压力计、声速计等数据的水下声学惯导计量技术,它能够实现厘米级的测量精度,而且作业方式简单,不受水深和能见度的限制,可有效提高海上工作效率,节约海上施工成本.

  18. 3D-SEM Metrology for Coordinate Measurements at the Nanometer Scale

    DEFF Research Database (Denmark)

    Carli, Lorenzo

    The present work deals with a study concerning 3D-SEM metrology as a tool for coordinate measurements at the nanometer scale. The relevance of 3D-SEM, based on stereophotogrammetry technique, has been highlighted with respect to the other measuring instruments nowadays available and the main issues...... to be addressed concerning uncertainty evaluation have been discussed. Most recent developments in the field of micro and nano-metrology, in terms of measuring machines and techniques, are described pointing out advantages and limitations. The importance of multi-sensor and multi-orientation strategy...... to 3D reconstructions, are given and the main phases involved in stereophotogrammetry technique are described underlying the most relevant error sources in the case of 2D and 3D-SEM metrology. An uncertainty evaluation has been thus carried out in accordance with ISO GUM, following a holistic approach...

  19. Corner cube model for Microarcsec Metrology (MAM) testbed in Space Interferometer Mission (SIM)

    Science.gov (United States)

    Wang, Xu

    2005-02-01

    A corner cube model is developed to calculate the SIM internal metrology optical delay bias (with the accuracy of picometer) due to the component imperfections, such as vertex offset, coating index error, dihedral error, and gimbal offset. This physics-based and Matlab-implemented ray-trace model provides useful guidance on the flight system design, integration, and characterization. In this paper, the details of the corner cube model will be described first. Then the sub-nanometer level model validation through the MAM testbed will be presented. Finally several examples of the model application, such as the metrology delay bias minimization, design parameter error budget (or tolerance) allocation, and the metrology beam prints visualization, will be shown.

  20. Spectroscopic metrology for isotope composition measurements and transfer standards

    Science.gov (United States)

    Anyangwe Nwaboh, Javis; Balslev-Harder, David; Kääriäinen, Teemu; Richmond, Craig; Manninen, Albert; Mohn, Joachim; Kiseleva, Maria; Petersen, Jan C.; Werhahn, Olav; Ebert, Volker

    2017-04-01

    The World Meteorological Organization (WMO) has identified greenhouse gases such as CO2, CH4 and N2O as critical for global climate monitoring. Other molecules such as CO that has an indirect effect of enhancing global warming are also monitored. WMO has stated compatibility goals for atmospheric concentration and isotope ratio measurements of these gases, e.g. 0.1 ppm for CO2 concentration measurements in the northern hemisphere and 0.01 ‰ for δ13C-CO2. For measurements of the concentration of greenhouse gases, gas analysers are typically calibrated with static gas standards e.g. traceable to the WMO scale or to the International System of Units (SI) through a national metrology institute. However, concentrations of target components, e.g. CO, in static gas standards have been observed to drift, and typically the gas matrix as well as the isotopic composition of the target component does not always reflect field gas composition, leading to deviations of the analyser response, even after calibration. The deviations are dependent on the measurement technique. To address this issue, part of the HIGHGAS (Metrology for high-impact greenhouse gases) project [1] focused on the development of optical transfer standards (OTSs) for greenhouse gases, e.g. CO2 and CO, potentially complementing gas standards. Isotope ratio mass spectrometry (IRMS) [2] is currently used to provide state-of-the-art high precision (in the 0.01 ‰ range) measurements for the isotopic composition of greenhouse gases. However, there is a need for field-deployable techniques such as optical isotope ratio spectroscopy (OIRS) that can be combined with metrological measurement methods. Within the HIGHGAS project, OIRS methods and procedures based on e.g. cavity enhanced spectroscopy (CES) and tunable diode laser absorption spectroscopy (TDLAS), matched to metrological principles have been established for the measurement of 13C/12C and 18O/16O ratios in CO2, 15N/14N ratios in N2O, and 13C/12C and 2H

  1. Polarization-insensitive FSS-based perfect metamaterial absorbers for GHz and THz frequencies

    National Research Council Canada - National Science Library

    Cumali Sabah; Furkan Dincer; Muharrem Karaaslan; Emin Unal; Oguzhan Akgol

    2014-01-01

      New perfect frequency selective surface (FSS) metamaterial absorbers (MAs) based on resonator with dielectric configuration are numerically presented and investigated for both microwave and terahertz frequency ranges...

  2. Metrology with PT-Symmetric Cavities: Enhanced Sensitivity near the PT-Phase Transition.

    Science.gov (United States)

    Liu, Zhong-Peng; Zhang, Jing; Özdemir, Şahin Kaya; Peng, Bo; Jing, Hui; Lü, Xin-You; Li, Chun-Wen; Yang, Lan; Nori, Franco; Liu, Yu-Xi

    2016-09-09

    We propose and analyze a new approach based on parity-time (PT) symmetric microcavities with balanced gain and loss to enhance the performance of cavity-assisted metrology. We identify the conditions under which PT-symmetric microcavities allow us to improve sensitivity beyond what is achievable in loss-only systems. We discuss the application of PT-symmetric microcavities to the detection of mechanical motion, and show that the sensitivity is significantly enhanced near the transition point from unbroken- to broken-PT regimes. Our results open a new direction for PT-symmetric physical systems and it may find use in ultrahigh precision metrology and sensing.

  3. Preface: The 5th International Workshop on X-ray Mirror Design, Fabrication, and Metrology.

    Science.gov (United States)

    Assoufid, Lahsen; Goldberg, Kenneth; Yashchuk, Valeriy V

    2016-05-01

    Recent developments in synchrotron storage rings and free-electron laser-based x-ray sources with ever-increasing brightness and coherent flux have pushed x-ray optics requirements to new frontiers. This Special Topic gathers a set of articles derived from a subset of the key presentations of the International Workshop on X-ray Mirrors Fabrication (IWXM-2015) and Metrology held at Lawrence Berkley National Laboratory, Berkeley, California, USA, July 14-16, 2015. The workshop objective was to report on recent progress in x-ray synchrotron radiation mirrors fabrication as well as on new developments in related metrology tools and methods.

  4. Target-Tracking Camera for a Metrology System

    Science.gov (United States)

    Liebe, Carl; Bartman, Randall; Chapsky, Jacob; Abramovici, Alexander; Brown, David

    2009-01-01

    An analog electronic camera that is part of a metrology system measures the varying direction to a light-emitting diode that serves as a bright point target. In the original application for which the camera was developed, the metrological system is used to determine the varying relative positions of radiating elements of an airborne synthetic aperture-radar (SAR) antenna as the airplane flexes during flight; precise knowledge of the relative positions as a function of time is needed for processing SAR readings. It has been common metrology system practice to measure the varying direction to a bright target by use of an electronic camera of the charge-coupled-device or active-pixel-sensor type. A major disadvantage of this practice arises from the necessity of reading out and digitizing the outputs from a large number of pixels and processing the resulting digital values in a computer to determine the centroid of a target: Because of the time taken by the readout, digitization, and computation, the update rate is limited to tens of hertz. In contrast, the analog nature of the present camera makes it possible to achieve an update rate of hundreds of hertz, and no computer is needed to determine the centroid. The camera is based on a position-sensitive detector (PSD), which is a rectangular photodiode with output contacts at opposite ends. PSDs are usually used in triangulation for measuring small distances. PSDs are manufactured in both one- and two-dimensional versions. Because it is very difficult to calibrate two-dimensional PSDs accurately, the focal-plane sensors used in this camera are two orthogonally mounted one-dimensional PSDs.

  5. High Frequency Performance of GaN Based IMPATT Diodes

    Directory of Open Access Journals (Sweden)

    B. Chakrabarti

    2011-08-01

    Full Text Available IMPATT is a p+n junction diode reversed bias to breakdown and can generate microwave power when properly embedded in a resonant cavity. Till emergence on 1965 day by day it became more powerful solid state source for microwave as well as mm-wave frequency range. To get higher efficiency and power output different structures like SDR, DDR, DAR, lo-high-lo, etc. were proposed and developed by different scientists over the years. Then the IMPATT development started with different semiconductor materials like GaAs, InP, GaN, etc. along with Silicon to achieve higher efficiency, power output and frequency range. In this paper the performance of GaN based SDR IMPATT have thoroughly studied in terms of (i electric field profile[E(x] (iinormalized current density profile [P(x] (iii Susceptance Vs Conductance characteristics (ivRF power output (v negative resistivity profile [R(x] of the diodes through simulation scheme. It is being observed that the efficiency is 17.9% at Ka-band and because of the very high breakdown voltage, power output is as high as1.56W in comparison with other frequency band of operations.

  6. Frequency selective surfaces based high performance microstrip antenna

    CERN Document Server

    Narayan, Shiv; Jha, Rakesh Mohan

    2016-01-01

    This book focuses on performance enhancement of printed antennas using frequency selective surfaces (FSS) technology. The growing demand of stealth technology in strategic areas requires high-performance low-RCS (radar cross section) antennas. Such requirements may be accomplished by incorporating FSS into the antenna structure either in its ground plane or as the superstrate, due to the filter characteristics of FSS structure. In view of this, a novel approach based on FSS technology is presented in this book to enhance the performance of printed antennas including out-of-band structural RCS reduction. In this endeavor, the EM design of microstrip patch antennas (MPA) loaded with FSS-based (i) high impedance surface (HIS) ground plane, and (ii) the superstrates are discussed in detail. The EM analysis of proposed FSS-based antenna structures have been carried out using transmission line analogy, in combination with the reciprocity theorem. Further, various types of novel FSS structures are considered in desi...

  7. Overlay metrology solutions in a triple patterning scheme

    Science.gov (United States)

    Leray, Philippe; Mao, Ming; Baudemprez, Bart; Amir, Nuriel

    2015-03-01

    Overlay metrology tool suppliers are offering today several options to their customers: Different hardware (Image Based Overlay or Diffraction Based Overlay), different target designs (with or without segmentation) or different target sizes (from 5 um to 30 um). All these variations are proposed to resolve issues like robustness of the target towards process variations, be more representative of the design or increase the density of measurements. In the frame of the development of a triple patterning BEOL scheme of 10 nm node layer, we compare IBO targets (standard AIM, AIMid and multilayer AIMid). The metrology tools used for the study are KLA-Tencor's nextgeneration Archer 500 system (scatterometry- and imaging-based measurement technologies on the same tool). The overlay response and fingerprint of these targets will be compared using a very dense sampling (up to 51 pts per field). The benefit of indie measurements compared to the traditional scribes is discussed. The contribution of process effects to overlay values are compared to the contribution of the performance of the target. Different targets are combined in one measurement set to benefit from their different strengths (performance vs size). The results are summarized and possible strategies for a triple patterning schemes are proposed.

  8. Highly sensitive passive radio frequency identification based sensor systems.

    Science.gov (United States)

    Wissenwasser, J; Vellekoop, M; Heer, R

    2010-02-01

    A novel platform for sensor applications based on radio frequency (rf) identification technology, where passive tags are powered by the rf-field of a reader, is presented. The sophisticated energy harvesting system of the tag enables a blanking of the rf-field for a defined period, while supplying the tag electronics with a highly stable voltage and a power of 25 mW for 100 ms. During this time, span measurements can be performed without interferences of the rf-field. The presented tags work without batteries and are designed for impedance measurements on microbiological cell cultures under physiological relevant conditions as well as in harsh environments.

  9. Highly sensitive passive radio frequency identification based sensor systems

    Science.gov (United States)

    Wissenwasser, J.; Vellekoop, M.; Heer, R.

    2010-02-01

    A novel platform for sensor applications based on radio frequency (rf) identification technology, where passive tags are powered by the rf-field of a reader, is presented. The sophisticated energy harvesting system of the tag enables a blanking of the rf-field for a defined period, while supplying the tag electronics with a highly stable voltage and a power of 25 mW for 100 ms. During this time, span measurements can be performed without interferences of the rf-field. The presented tags work without batteries and are designed for impedance measurements on microbiological cell cultures under physiological relevant conditions as well as in harsh environments.

  10. An Improved Variable-Frequency Drive Based on Current Tracking

    Directory of Open Access Journals (Sweden)

    Zhiwei He

    2013-11-01

    Full Text Available Variable frequency devices are widely used in many power systems. A current tracking based VFD is proposed in this paper. The output current is firstly fed back and compared with a standard sine wave, the difference of them is then used for a PI regulator to control the PWM signal, so as to change the output current accordingly to make it approach the standard sine wave. Simulation and experiments results show that the current tracking VFD not only has a fast dynamic response, high current tracking precision, current limiting ability, but also has small distortion of the output sine wave current and low loss of the motor.    

  11. DOPPLERLET BASED TIME-FREQUENCY REPRESENTATION VIA MATCHING PURSUITS

    Institute of Scientific and Technical Information of China (English)

    Zou Hongxing; Zhou Xiaobo; Dai Qionghai; Li Yanda

    2001-01-01

    A new time-frequency representation called Dopplerlet transform, which uses the dilated, translated and modulated windowed Doppler signals as its basis functions, is proposed, and the Fourier transform, short-time Fourier transform (including Gabor transform), wavelet transform, and chirplet transform are formulated in one framework of Dopplerlet transform accordingly.It is proved that the matching pursuits based on Dopplerlet basis functions are convergent, and that the energy of residual signals yielded in the decomposition process decays exponentially. Simulation results show that the matching pursuits with Dopplerlet basis functions can characterize compactly a nonstationary signal.

  12. EDITORIAL: Standard Materials and Metrology for Nanotechnology (SMAM-2)

    Science.gov (United States)

    Ichimura, Shingo; Kurosawa, Tomizo; Fujimoto, Toshiyuki; Nonaka, Hidehiko

    2007-09-01

    This issue of Measurement Science and Technology (MST) contains three papers presented at the second international symposium on Standard Materials and Metrology for Nanotechnology (SMAM-2), held in the Akihabara Convention Hall in Tokyo, Japan, on 25 and 26 May 2006. The SMAM symposium aims to emphasize the importance of standard materials and metrology (SM/M) for the development of nanotechnology, which is expected to be the most promising driving force for the development of advanced industrial science/technology in various fields. New fabrication processes based on nanotechnology will become really powerful when the processes are reproducible and reliable. The SM/M that have been developed for use in nano-scale characterization are therefore the key tools for the establishment of reliability in the areas of information, environment and biotechnology, where the application of nanotechnology is essential for their development. The symposium had four sessions featuring the most important issues in the field of SM/M: (I) Nanotechnology Standardization, (II) SM/M for Nano-particles and Nano-pores, (III) SM/M for Nanostructure Evaluation, (IV) SM/M for Thin-film Characterization. A total of 29 papers had been submitted to the SMAM-2 Publishing Committee and six papers were tentatively selected by the committee to forward to the MST editors for publication in this journal. The three papers published in this issue are epoch-making in that they present new methods and knowledge for the standard materials and metrology especially developed for nanotechnology. We hope the papers will show readers how important standard materials and metrology are for the development of nanotechnology. We appreciate very much the important contribution of those who refereed the manuscripts and we particularly want to thank the MST staff for helping in publishing this special feature. Finally we expect SMAM-3 to be held two years after SMAM-2 and we hope to attract many more participants and

  13. Comparison of metatranscriptomic samples based on k-tuple frequencies.

    Directory of Open Access Journals (Sweden)

    Ying Wang

    Full Text Available BACKGROUND: The comparison of samples, or beta diversity, is one of the essential problems in ecological studies. Next generation sequencing (NGS technologies make it possible to obtain large amounts of metagenomic and metatranscriptomic short read sequences across many microbial communities. De novo assembly of the short reads can be especially challenging because the number of genomes and their sequences are generally unknown and the coverage of each genome can be very low, where the traditional alignment-based sequence comparison methods cannot be used. Alignment-free approaches based on k-tuple frequencies, on the other hand, have yielded promising results for the comparison of metagenomic samples. However, it is not known if these approaches can be used for the comparison of metatranscriptome datasets and which dissimilarity measures perform the best. RESULTS: We applied several beta diversity measures based on k-tuple frequencies to real metatranscriptomic datasets from pyrosequencing 454 and Illumina sequencing platforms to evaluate their effectiveness for the clustering of metatranscriptomic samples, including three d2-type dissimilarity measures, one dissimilarity measure in CVTree, one relative entropy based measure S2 and three classical 1p-norm distances. Results showed that the measure d2(S can achieve superior performance on clustering metatranscriptomic samples into different groups under different sequencing depths for both 454 and Illumina datasets, recovering environmental gradients affecting microbial samples, classifying coexisting metagenomic and metatranscriptomic datasets, and being robust to sequencing errors. We also investigated the effects of tuple size and order of the background Markov model. A software pipeline to implement all the steps of analysis is built and is available at http://code.google.com/p/d2-tools/. CONCLUSIONS: The k-tuple based sequence signature measures can effectively reveal major groups and

  14. [Frequency-domain quantification based on the singular value decomposition and frequency-selection for magnetic resonance spectra].

    Science.gov (United States)

    Men, Kuo; Quan, Hong; Yang, Peipei; Cao, Ting; Li, Weihao

    2010-04-01

    The frequency-domain magnetic resonance spectroscopy (MRS) is achieved by the Fast Fourier Transform (FFT) of the time-domain signals. Usually we are only interested in the portion lying in a frequency band of the whole spectrum. A method based on the singular value decomposition (SVD) and frequency-selection is presented in this article. The method quantifies the spectrum lying in the interested frequency band and reduces the interference of the parts lying out of the band in a computationally efficient way. Comparative experiments with the standard time-domain SVD method indicate that the method introduced in this article is accurate and timesaving in practical situations.

  15. Metrology, applications and methods with high energy CT systems

    Energy Technology Data Exchange (ETDEWEB)

    Uhlmann, N.; Voland, V.; Salamon, M.; Hebele, S.; Boehnel, M.; Reims, N.; Schmitt, M.; Kasperl, S. [Fraunhofer IIS/EZRT, Development Center X-Ray Technology, Flugplatzstrasse 75, 90768 Fürth (Germany); Hanke, R. [Chair of X-ray Microscopy, University of Würzburg - Physics and Astronomy (Germany)

    2014-02-18

    The increase of Computed Tomography (CT) as an applicable metrology and Non Destructive Testing (NDT) method raises interest on developing the application fields to larger objects, which were rarely used in the past due to their requirements on the imaging system. Especially the classical X-ray generation techniques based on standard equipment restricted the applications of CT to typical material penetration lengths of only a few cm of steel. Even with accelerator technology that offers a suitable way to overcome these restrictions just the 2D radioscopy technique found a widespread application. Beside the production and detection of photons in the MeV range itself, the achievable image quality is limited using standard detectors due to the dominating absorption effect of Compton Scattering at high energies. Especially for CT reconstruction purposes these effects have to be considered on the development path from 2D to 3D imaging. Most High Energy CT applications are therefore based on line detectors shielding scattered radiation to a maximum with an increase in imaging quality but with time consuming large volume scan capabilities. In this contribution we present the High-Energy X-ray Imaging project at the Fraunhofer Development Centre for X-ray Technology with the characterization and the potential of the CT-system according to metrological and other application capabilities.

  16. X-ray pulse wavefront metrology using speckle tracking

    Energy Technology Data Exchange (ETDEWEB)

    Berujon, Sebastien, E-mail: berujon@esrf.eu; Ziegler, Eric; Cloetens, Peter [European Synchrotron Radiation Facility, BP-220, F-38043 Grenoble (France)

    2015-05-09

    The theoretical description and experimental implementation of a speckle-tracking-based instrument which permits the characterisation of X-ray pulse wavefronts. An instrument allowing the quantitative analysis of X-ray pulsed wavefronts is presented and its processing method explained. The system relies on the X-ray speckle tracking principle to accurately measure the phase gradient of the X-ray beam from which beam optical aberrations can be deduced. The key component of this instrument, a semi-transparent scintillator emitting visible light while transmitting X-rays, allows simultaneous recording of two speckle images at two different propagation distances from the X-ray source. The speckle tracking procedure for a reference-less metrology mode is described with a detailed account on the advanced processing schemes used. A method to characterize and compensate for the imaging detector distortion, whose principle is also based on speckle, is included. The presented instrument is expected to find interest at synchrotrons and at the new X-ray free-electron laser sources under development worldwide where successful exploitation of beams relies on the availability of an accurate wavefront metrology.

  17. LPI Radar Waveform Recognition Based on Time-Frequency Distribution.

    Science.gov (United States)

    Zhang, Ming; Liu, Lutao; Diao, Ming

    2016-10-12

    In this paper, an automatic radar waveform recognition system in a high noise environment is proposed. Signal waveform recognition techniques are widely applied in the field of cognitive radio, spectrum management and radar applications, etc. We devise a system to classify the modulating signals widely used in low probability of intercept (LPI) radar detection systems. The radar signals are divided into eight types of classifications, including linear frequency modulation (LFM), BPSK (Barker code modulation), Costas codes and polyphase codes (comprising Frank, P1, P2, P3 and P4). The classifier is Elman neural network (ENN), and it is a supervised classification based on features extracted from the system. Through the techniques of image filtering, image opening operation, skeleton extraction, principal component analysis (PCA), image binarization algorithm and Pseudo-Zernike moments, etc., the features are extracted from the Choi-Williams time-frequency distribution (CWD) image of the received data. In order to reduce the redundant features and simplify calculation, the features selection algorithm based on mutual information between classes and features vectors are applied. The superiority of the proposed classification system is demonstrated by the simulations and analysis. Simulation results show that the overall ratio of successful recognition (RSR) is 94.7% at signal-to-noise ratio (SNR) of -2 dB.

  18. LPI Radar Waveform Recognition Based on Time-Frequency Distribution

    Directory of Open Access Journals (Sweden)

    Ming Zhang

    2016-10-01

    Full Text Available In this paper, an automatic radar waveform recognition system in a high noise environment is proposed. Signal waveform recognition techniques are widely applied in the field of cognitive radio, spectrum management and radar applications, etc. We devise a system to classify the modulating signals widely used in low probability of intercept (LPI radar detection systems. The radar signals are divided into eight types of classifications, including linear frequency modulation (LFM, BPSK (Barker code modulation, Costas codes and polyphase codes (comprising Frank, P1, P2, P3 and P4. The classifier is Elman neural network (ENN, and it is a supervised classification based on features extracted from the system. Through the techniques of image filtering, image opening operation, skeleton extraction, principal component analysis (PCA, image binarization algorithm and Pseudo–Zernike moments, etc., the features are extracted from the Choi–Williams time-frequency distribution (CWD image of the received data. In order to reduce the redundant features and simplify calculation, the features selection algorithm based on mutual information between classes and features vectors are applied. The superiority of the proposed classification system is demonstrated by the simulations and analysis. Simulation results show that the overall ratio of successful recognition (RSR is 94.7% at signal-to-noise ratio (SNR of −2 dB.

  19. Development of Frequency Based Taste Receptors Using Bioinspired Glucose Nanobiosensor.

    Science.gov (United States)

    TermehYousefi, Amin; Tateno, Katsumi; Bagheri, Samira; Tanaka, Hirofumi

    2017-05-09

    A method to fabricate a bioinspired nanobiosensor using electronic-based artificial taste receptors for glucose diagnosis is presented. Fabricated bioinspired glucose nanobiosensor designated based on an artificial taste bud including an amperometric glucose biosensor and taste bud-inspired circuits. In fact, the design of the taste bud-inspired circuits was inspired by the signal-processing mechanism of taste nerves which involves two layers. The first, known as a type II cell, detects the glucose by glucose oxidase and transduces the current signal obtained for the pulse pattern is conducted to the second layer, called type III cell, to induce synchronisation of the neural spiking activity. The oscillation results of fabricated bioinspired glucose nanobiosensor confirmed an increase in the frequency of the output pulse as a function of the glucose concentration. At high glucose concentrations, the bioinspired glucose nanobiosensor showed a pulse train of alternating short and long interpulse intervals. A computational analysis performed to validate the hypothesis, which was successfully reproduced the alternating behaviour of bioinspired glucose our nanobiosensor by increasing the output frequency and alternation of pulse intervals according to the reduction in the resistivity of the biosensor.

  20. Ultra High-Speed Radio Frequency Switch Based on Photonics.

    Science.gov (United States)

    Ge, Jia; Fok, Mable P

    2015-11-26

    Microwave switches, or Radio Frequency (RF) switches have been intensively used in microwave systems for signal routing. Compared with the fast development of microwave and wireless systems, RF switches have been underdeveloped particularly in terms of switching speed and operating bandwidth. In this paper, we propose a photonics based RF switch that is capable of switching at tens of picoseconds speed, which is hundreds of times faster than any existing RF switch technologies. The high-speed switching property is achieved with the use of a rapidly tunable microwave photonic filter with tens of gigahertz frequency tuning speed, where the tuning mechanism is based on the ultra-fast electro-optics Pockels effect. The RF switch has a wide operation bandwidth of 12 GHz and can go up to 40 GHz, depending on the bandwidth of the modulator used in the scheme. The proposed RF switch can either work as an ON/OFF switch or a two-channel switch, tens of picoseconds switching speed is experimentally observed for both type of switches.

  1. A Frequency-Based Approach to Intrusion Detection

    Directory of Open Access Journals (Sweden)

    Mian Zhou

    2004-06-01

    Full Text Available Research on network security and intrusion detection strategies presents many challenging issues to both theoreticians and practitioners. Hackers apply an array of intrusion and exploit techniques to cause disruption of normal system operations, but on the defense, firewalls and intrusion detection systems (IDS are typically only effective in defending known intrusion types using their signatures, and are far less than mature when faced with novel attacks. In this paper, we adapt the frequency analysis techniques such as the Discrete Fourier Transform (DFT used in signal processing to the design of intrusion detection algorithms. We demonstrate the effectiveness of the frequency-based detection strategy by running synthetic network intrusion data in simulated networks using the OPNET software. The simulation results indicate that the proposed intrusion detection strategy is effective in detecting anomalous traffic data that exhibit patterns over time, which include several types of DOS and probe attacks. The significance of this new strategy is that it does not depend on the prior knowledge of attack signatures, thus it has the potential to be a useful supplement to existing signature-based IDS and firewalls.

  2. Full stabilization of a microresonator-based optical frequency comb.

    Science.gov (United States)

    Del'Haye, P; Arcizet, O; Schliesser, A; Holzwarth, R; Kippenberg, T J

    2008-08-01

    We demonstrate control and stabilization of an optical frequency comb generated by four-wave mixing in a monolithic microresonator with a mode spacing in the microwave regime (86 GHz). The comb parameters (mode spacing and offset frequency) are controlled via the power and the frequency of the pump laser, which constitutes one of the comb modes. Furthermore, generation of a microwave beat note at the comb's mode spacing frequency is demonstrated, enabling direct stabilization to a microwave frequency standard.

  3. FOREWORD: Special issue on Statistical and Probabilistic Methods for Metrology

    Science.gov (United States)

    Bich, Walter; Cox, Maurice G.

    2006-08-01

    for Metrology programme in the UK, which includes within its main themes generic items related to modelling, uncertainty evaluation and key comparisons. There are also teams concentrating on statistics within a metrology environment, the largest of which is the Statistical Engineering Division at NIST. There are, however, key pockets of mathematical and statistical expertise at all major and many of the smaller NMIs. Academia also makes considerable input to metrological thinking. The papers in this special issue reflect the above considerations—and more. There are several offerings relating to the GUM: (a) the manner in which the GUM is evolving, especially through Supplements to the GUM, (b) a comparison of the GUM, the GUM Supplement concerned with the propagation of distributions and Bayesian statistics, in the context of linear calibration, (c) theoretical and practical aspects of the use of a Monte Carlo method for propagating distributions, (d) the use of a generalization of the sensitivity coefficients in the GUM to correlated quantities, and (e) considerations on obtaining best estimates when the model is non-linear. At a more fundamental level, a systematic and versatile approach to developing the model of measurement, on which uncertainty evaluation is of course based, is presented, and a paper is included on principles of probability and statistics that promote sound decision-making. The evaluation of key comparison data is represented in terms of contributions relating to (a) models of key comparisons, with measures of operability and interoperability, (b) a Bayesian procedure for providing PDFs from which the measures required by the MRA can be extracted, (c) an extension of the En measure familiar to many metrologists, and (d) the use of the median and weighted median as the key comparison reference value in the presence of discrepant measurement results. The remaining contributions concern the analysis of measurement data, including spectral analysis

  4. Quantum control, quantum information processing, and quantum-limited metrology with trapped ions

    CERN Document Server

    Wineland, D J; Barrett, M D; Ben-Kish, A; Bergquist, J C; Blakestad, R B; Bollinger, J J; Britton, J L; Chiaverini, J; De Marco, B L; Hume, D; Itano, W M; Jensen, M; Jost, J D; Knill, E; Koelemeij, J C J; Langer, C; Oskay, W; Ozeri, R; Reichle, R; Rosenband, T; Schätz, T; Schmidt, P O; Seidelin, S

    2005-01-01

    We briefly discuss recent experiments on quantum information processing using trapped ions at NIST. A central theme of this work has been to increase our capabilities in terms of quantum computing protocols, but we have also applied the same concepts to improved metrology, particularly in the area of frequency standards and atomic clocks. Such work may eventually shed light on more fundamental issues, such as the quantum measurement problem.

  5. Freeform metrology using subaperture stitching interferometry

    Science.gov (United States)

    Supranowitz, Chris; Lormeau, Jean-Pierre; Maloney, Chris; Murphy, Paul; Dumas, Paul

    2016-11-01

    As applications for freeform optics continue to grow, the need for high-precision metrology is becoming more of a necessity. Currently, coordinate measuring machines (CMM) that implement touch probes or optical probes can measure the widest ranges of shapes of freeform optics, but these measurement solutions often lack sufficient lateral resolution and accuracy. Subaperture stitching interferometry (SSI™) extends traditional Fizeau interferometry to provide accurate, high-resolution measurements of flats, spheres, and aspheres, and development is currently on-going to enable measurements of freeform surfaces. We will present recent freeform metrology results, including repeatability and cross-test data. We will also present MRF® polishing results where the stitched data was used as the input "hitmap" to the deterministic polishing process.

  6. Machine tool metrology an industrial handbook

    CERN Document Server

    Smith, Graham T

    2016-01-01

    Maximizing reader insights into the key scientific disciplines of Machine Tool Metrology, this text will prove useful for the industrial-practitioner and those interested in the operation of machine tools. Within this current level of industrial-content, this book incorporates significant usage of the existing published literature and valid information obtained from a wide-spectrum of manufacturers of plant, equipment and instrumentation before putting forward novel ideas and methodologies. Providing easy to understand bullet points and lucid descriptions of metrological and calibration subjects, this book aids reader understanding of the topics discussed whilst adding a voluminous-amount of footnotes utilised throughout all of the chapters, which adds some additional detail to the subject. Featuring an extensive amount of photographic-support, this book will serve as a key reference text for all those involved in the field. .

  7. Compressed quantum metrology for the Ising Hamiltonian

    Science.gov (United States)

    Boyajian, W. L.; Skotiniotis, M.; Dür, W.; Kraus, B.

    2016-12-01

    We show how quantum metrology protocols that seek to estimate the parameters of a Hamiltonian that exhibits a quantum phase transition can be efficiently simulated on an exponentially smaller quantum computer. Specifically, by exploiting the fact that the ground state of such a Hamiltonian changes drastically around its phase-transition point, we construct a suitable observable from which one can estimate the relevant parameters of the Hamiltonian with Heisenberg scaling precision. We then show how, for the one-dimensional Ising Hamiltonian with transverse magnetic field acting on N spins, such a metrology protocol can be efficiently simulated on an exponentially smaller quantum computer while maintaining the same Heisenberg scaling for the squared error, i.e., O (N-2) precision, and derive the explicit circuit that accomplishes the simulation.

  8. Quantum metrology and estimation of Unruh effect.

    Science.gov (United States)

    Wang, Jieci; Tian, Zehua; Jing, Jiliang; Fan, Heng

    2014-11-26

    We study the quantum metrology for a pair of entangled Unruh-Dewitt detectors when one of them is accelerated and coupled to a massless scalar field. Comparing with previous schemes, our model requires only local interaction and avoids the use of cavities in the probe state preparation process. We show that the probe state preparation and the interaction between the accelerated detector and the external field have significant effects on the value of quantum Fisher information, correspondingly pose variable ultimate limit of precision in the estimation of Unruh effect. We find that the precision of the estimation can be improved by a larger effective coupling strength and a longer interaction time. Alternatively, the energy gap of the detector has a range that can provide us a better precision. Thus we may adjust those parameters and attain a higher precision in the estimation. We also find that an extremely high acceleration is not required in the quantum metrology process.

  9. Metrology for fire experiments in outdoor conditions

    CERN Document Server

    Silvani, Xavier

    2013-01-01

    Natural fires can be considered as scale-dependant, non-linear processes of mass, momentum and heat transport, resulting from a turbulent reactive and radiative fluid medium flowing over a complex medium, the vegetal fuel. In natural outdoor conditions, the experimental study of natural fires at real scale needs the development of an original metrology, one able to capture the large range of time and length scales involved in its dynamic nature and also able to resist the thermal, mechanical and chemical aggression of flames on devices. Robust, accurate and poorly intrusive tools must be carefully set-up and used for gaining very fluctuating data over long periods. These signals also need the development of original post-processing tools that take into account the non-steady nature of their stochastic components. Metrology for Fire Experiments in Outdoor Conditions closely analyzes these features, and also describes measurements techniques, the thermal insulation of fragile electronic systems, data acquisitio...

  10. Reference Materials for Food and Nutrition Metrology: Past, Present and Future

    Science.gov (United States)

    Establishment of a metrology-based measurement system requires the solid foundation of traceability of measurements to available, appropriate certified reference materials (CRM). In the early 1970’s the first “biological” RM of Bowens Kale, as well as Orchard Leaves and Bovine Liver SRMs, from the ...

  11. Cryogenic current comparators with optimum SQUID readout for current and resistance quantum metrology

    NARCIS (Netherlands)

    Bartolomé Porcar, María Elena

    2002-01-01

    This thesis describes the development of several systems based on the Cryogenic Current Comparator with optimum SQUID readout, for current and resistance metrology applications. the CCC-SQUID is at present the most accurate current comparator available. A (type I) CCC consists basically of a

  12. Frequency-based image analysis of random patterns: an alternative way to classical stereocorrelation

    CERN Document Server

    Molimard, Jérôme; Zahouani, Hassan

    2013-01-01

    The paper presents an alternative way to classical stereocorrelation. First, 2D image processing of random patterns is described. Sub-pixel displacements are determined using phase analysis. Then distortion evaluation is presented. The distortion is identified without any assumption on the lens model because of the use of a grid technique approach. Last, shape measurement and shape variation is caught by fringe projection. Analysis is based on two pin-hole assumptions for the video-projector and the camera. Then, fringe projection is coupled to in-plane displacement to give rise to 3D measurement set-up. Metrological characterization shows a resolution comparable to classical (stereo) correlation technique (1/100th pixel). Spatial resolution seems to be an advantage of the method, because of the use of temporal phase stepping (shape measurement, 1 pixel) and windowed Fourier transform (in plane displacements measurement, 9 pixels). Two examples are given. First one is the study of skin properties; second one ...

  13. Digital holography for MEMS and microsystem metrology

    CERN Document Server

    Asundi, Anand

    2011-01-01

    Approaching the topic of digital holography from the practical perspective of industrial inspection, Digital Holography for MEMS and Microsystem Metrology describes the process of digital holography and its growing applications for MEMS characterization, residual stress measurement, design and evaluation, and device testing and inspection. Asundi also provides a thorough theoretical grounding that enables the reader to understand basic concepts and thus identify areas where this technique can be adopted. This combination of both practical and theoretical approach will ensure the

  14. Quantum metrology and its application in biology

    Science.gov (United States)

    Taylor, Michael A.; Bowen, Warwick P.

    2016-02-01

    Quantum metrology provides a route to overcome practical limits in sensing devices. It holds particular relevance to biology, where sensitivity and resolution constraints restrict applications both in fundamental biophysics and in medicine. Here, we review quantum metrology from this biological context, focusing on optical techniques due to their particular relevance for biological imaging, sensing, and stimulation. Our understanding of quantum mechanics has already enabled important applications in biology, including positron emission tomography (PET) with entangled photons, magnetic resonance imaging (MRI) using nuclear magnetic resonance, and bio-magnetic imaging with superconducting quantum interference devices (SQUIDs). In quantum metrology an even greater range of applications arise from the ability to not just understand, but to engineer, coherence and correlations at the quantum level. In the past few years, quite dramatic progress has been seen in applying these ideas into biological systems. Capabilities that have been demonstrated include enhanced sensitivity and resolution, immunity to imaging artefacts and technical noise, and characterization of the biological response to light at the single-photon level. New quantum measurement techniques offer even greater promise, raising the prospect for improved multi-photon microscopy and magnetic imaging, among many other possible applications. Realization of this potential will require cross-disciplinary input from researchers in both biology and quantum physics. In this review we seek to communicate the developments of quantum metrology in a way that is accessible to biologists and biophysicists, while providing sufficient details to allow the interested reader to obtain a solid understanding of the field. We further seek to introduce quantum physicists to some of the central challenges of optical measurements in biological science. We hope that this will aid in bridging the communication gap that exists

  15. Quantum metrology and its application in biology

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Michael A. [Centre for Engineered Quantum Systems, University of Queensland, St Lucia, Queensland 4072 (Australia); Research Institute of Molecular Pathology (IMP), Max F. Perutz Laboratories & Research Platform for Quantum Phenomena and Nanoscale Biological Systems (QuNaBioS), University of Vienna, Dr. Bohr Gasse 7-9, A-1030 Vienna (Austria); Bowen, Warwick P., E-mail: w.bowen@uq.edu.au [Centre for Engineered Quantum Systems, University of Queensland, St Lucia, Queensland 4072 (Australia)

    2016-02-23

    Quantum metrology provides a route to overcome practical limits in sensing devices. It holds particular relevance to biology, where sensitivity and resolution constraints restrict applications both in fundamental biophysics and in medicine. Here, we review quantum metrology from this biological context, focusing on optical techniques due to their particular relevance for biological imaging, sensing, and stimulation. Our understanding of quantum mechanics has already enabled important applications in biology, including positron emission tomography (PET) with entangled photons, magnetic resonance imaging (MRI) using nuclear magnetic resonance, and bio-magnetic imaging with superconducting quantum interference devices (SQUIDs). In quantum metrology an even greater range of applications arise from the ability to not just understand, but to engineer, coherence and correlations at the quantum level. In the past few years, quite dramatic progress has been seen in applying these ideas into biological systems. Capabilities that have been demonstrated include enhanced sensitivity and resolution, immunity to imaging artefacts and technical noise, and characterization of the biological response to light at the single-photon level. New quantum measurement techniques offer even greater promise, raising the prospect for improved multi-photon microscopy and magnetic imaging, among many other possible applications. Realization of this potential will require cross-disciplinary input from researchers in both biology and quantum physics. In this review we seek to communicate the developments of quantum metrology in a way that is accessible to biologists and biophysicists, while providing sufficient details to allow the interested reader to obtain a solid understanding of the field. We further seek to introduce quantum physicists to some of the central challenges of optical measurements in biological science. We hope that this will aid in bridging the communication gap that exists

  16. Interpreting Quantum Discord in Quantum Metrology

    OpenAIRE

    Girolami, Davide

    2015-01-01

    Multipartite quantum systems show properties which do not admit a classical explanation. In particular, even nonentangled states can enjoy a kind of quantum correlations called quantum discord. I discuss some recent results on the role of quantum discord in metrology. Given an interferometric phase estimation protocol where the Hamiltonian is initially unknown to the experimentalist, the quantum discord of the probe state quantifies the minimum precision of the estimation. This provides a phy...

  17. Uterine metrology devices for IUD selection.

    Science.gov (United States)

    1981-11-01

    Accurate measurements of the length of the uterine cavity would make it feasible to select an IUD that is compatible with a given cavity size. Considerable evidence exists to indicate that selecting an IUD on the basis of accurate longitudinal measurements of the uterine cavity improves IUD performance. There are study findings to suggest that as more data are available, specific IUDs can be prescribed for defined ranges of uterine cavity length. Metrology (uterine measuring) devices improve the ability of the clinican to measure accurately longitudinal and, in some instances, lateral dimensions of the uterine cavity. Longitudinal measurements depend on identifying the location of the internal os in order to determine the total length of the cervical canal. Lateral metrology devices also provide a measurement of uterine cavity width. Pain and discomfort associated with the use of the prototype lateral measurement instruments developed thus far is a major deterrent to their wide-scale use. 2 metrology devices -- the Crochet Hook Sound and the Hasson Wing Sound -- are designed to obtain longitudinal measurements of total uterine cavity length and of the length of the cervical canel. 2 new instruments -- the Cavimeter and the Hasson Wing Sound 2 -- designed to obtain both lateral and longitudinal measurements are now available for evaluation. The Hasson Wing Sound appears to be the only uterine metrology device available for service programs that could affect continuation rates of IUD users. It can measure the length of the uterine cavity directly, thus permitting improved IUD selection of individual women or the ability to exclude women who should not be IUD users because of small uterine size. An illustration of the prescriptive approach is included in a table.

  18. High-frequency SAW filters based on diamond films.

    Science.gov (United States)

    Fujii, Satoshi; Jian, Chunyun

    2012-12-01

    We have developed a diamond SAW resonator capable of operating at frequencies over 3 GHz using a SiO(2)/ interdigital transducer (IDT)/AlN/diamond structure. This structure is expected to have a high Q value and a zero temperature coefficient of frequency (TCF) over 3 GHz, based on the high acoustic velocity of AlN. The SAW characteristics of various layered structures composed of SiO(2)/IDT/AlN/diamond substrates were studied both theoretically and experimentally. The SiO(2)/IDT/AlN/diamond substrate structure allows for a thicker IDT metal layer compared with other SAW device designs, such as the SiO(2)/IDT/ZnO/diamond structure. The thicker metal IDT in the present design leads to a lower series resistance and, in turn, a low insertion loss for SAW devices over 3 GHz. Using a second-mode (Sezawa-mode) SAW, the phase velocity and electromechanical coupling coefficient of the SiO(2)/IDT/AlN/diamond substrate reached the larger values of 11 150 m/s and 0.5%, respectively, and a zero TCF characteristic at 25°C was achieved. One-port SAW resonators fabricated from diamond substrates showed a high Q of 660 at 5.4 GHz. The frequency drift over a temperature range of -25°C to 80°C was about 90 ppm, even less than that for ST-quartz SAW substrates. A two-port resonator showed a low insertion loss of 8 dB at 5.4 GHz. Finally, we designed a 5-GHz band-stop SAW filter. A 30-MHz-wide stopband at a -6-dB rejection level was achieved while keeping the passband insertion loss to 0.76 dB. These characteristics of these filters show good potential for SHF-band filters.

  19. Tapered amplifier laser with frequency-shifted feedback

    CERN Document Server

    Bayerle, A; Vlaar, P; Pasquiou, B; Schreck, F

    2016-01-01

    We present a frequency-shifted feedback (FSF) laser based on a tapered amplifier. The laser operates as a coherent broadband source with up to 370GHz spectral width and 2.3us coherence time. If the FSF laser is seeded by a continuous-wave laser a frequency comb spanning the output spectrum appears in addition to the broadband emission. The laser has an output power of 280mW and a center wavelength of 780nm. The ease and flexibility of use of tapered amplifiers makes our FSF laser attractive for a wide range of applications, especially in metrology.

  20. Data fusion for accurate microscopic rough surface metrology.

    Science.gov (United States)

    Chen, Yuhang

    2016-06-01

    Data fusion for rough surface measurement and evaluation was analyzed on simulated datasets, one with higher density (HD) but lower accuracy and the other with lower density (LD) but higher accuracy. Experimental verifications were then performed on laser scanning microscopy (LSM) and atomic force microscopy (AFM) characterizations of surface areal roughness artifacts. The results demonstrated that the fusion based on Gaussian process models is effective and robust under different measurement biases and noise strengths. All the amplitude, height distribution, and spatial characteristics of the original sample structure can be precisely recovered, with better metrological performance than any individual measurements. As for the influencing factors, the HD noise has a relatively weaker effect as compared with the LD noise. Furthermore, to enable an accurate fusion, the ratio of LD sampling interval to surface autocorrelation length should be smaller than a critical threshold. In general, data fusion is capable of enhancing the nanometrology of rough surfaces by combining efficient LSM measurement and down-sampled fast AFM scan. The accuracy, resolution, spatial coverage and efficiency can all be significantly improved. It is thus expected to have potential applications in development of hybrid microscopy and in surface metrology.

  1. X-ray pulse wavefront metrology using speckle tracking.

    Science.gov (United States)

    Berujon, Sebastien; Ziegler, Eric; Cloetens, Peter

    2015-07-01

    An instrument allowing the quantitative analysis of X-ray pulsed wavefronts is presented and its processing method explained. The system relies on the X-ray speckle tracking principle to accurately measure the phase gradient of the X-ray beam from which beam optical aberrations can be deduced. The key component of this instrument, a semi-transparent scintillator emitting visible light while transmitting X-rays, allows simultaneous recording of two speckle images at two different propagation distances from the X-ray source. The speckle tracking procedure for a reference-less metrology mode is described with a detailed account on the advanced processing schemes used. A method to characterize and compensate for the imaging detector distortion, whose principle is also based on speckle, is included. The presented instrument is expected to find interest at synchrotrons and at the new X-ray free-electron laser sources under development worldwide where successful exploitation of beams relies on the availability of an accurate wavefront metrology.

  2. Vortex metrology using Fourier analysis techniques: vortex networks correlation fringes.

    Science.gov (United States)

    Angel-Toro, Luciano; Sierra-Sosa, Daniel; Tebaldi, Myrian; Bolognini, Néstor

    2012-10-20

    In this work, we introduce an alternative method of analysis in vortex metrology based on the application of the Fourier optics techniques. The first part of the procedure is conducted as is usual in vortex metrology for uniform in-plane displacement determination. On the basis of two recorded intensity speckled distributions, corresponding to two states of a diffuser coherently illuminated, we numerically generate an analytical signal from each recorded intensity pattern by using a version of the Riesz integral transform. Then, from each analytical signal, a two-dimensional pseudophase map is generated in which the vortices are located and characterized in terms of their topological charges and their core's structural properties. The second part of the procedure allows obtaining Young's interference fringes when Fourier transforming the light passing through a diffracting mask with multiple apertures at the locations of the homologous vortices. In fact, we use the Fourier transform as a mathematical operation to compute the far-field diffraction intensity pattern corresponding to the multiaperture set. Each aperture from the set is associated with a rectangular hole that coincides both in shape and size with a pixel from recorded images. We show that the fringe analysis can be conducted as in speckle photography in an extended range of displacement measurements. Effects related with speckled decorrelation are also considered. Our experimental results agree with those of speckle photography in the range in which both techniques are applicable.

  3. Metrology challenges for high-rate nanomanufacturing of polymer structures

    Science.gov (United States)

    Mead, Joey; Barry, Carol; Busnaina, Ahmed; Isaacs, Jacqueline

    2012-10-01

    The transfer of nanoscience accomplishments into commercial products is hindered by the lack of understanding of barriers to nanoscale manufacturing. We have developed a number of nanomanufacturing processes that leverage available high-rate plastics fabrication technologies. These processes include directed assembly of a variety of nanoelements, such as nanoparticles and nanotubes, which are then transferred onto a polymer substrate for the fabrication of conformal/flexible electronic materials, among other applications. These assembly processes utilize both electric fields and/or chemical functionalization. Conducting polymers and carbon nanotubes have been successfully transferred to a polymer substrate in times less than 5 minutes, which is commercially relevant and can be utilized in a continuous (reel to reel/roll to roll) process. Other processes include continuous high volume mixing of nanoelements (CNTs, etc) into polymers, multi-layer extrusion and 3D injection molding of polymer structures. These nanomanufacturing processes can be used for wide range of applications, including EMI shielding, flexible electronics, structural materials, and novel sensors (specifically for chem/bio detection). Current techniques to characterize the quality and efficacy of the processes are quite slow. Moreover, the instrumentation and metrology needs for these manufacturing processes are varied and challenging. Novel, rapid, in-line metrology to enable the commercialization of these processes is critically needed. This talk will explore the necessary measurement needs for polymer based nanomanufacturing processes for both step and continuous (reel to reel/roll to roll) processes.

  4. Frequency response function-based model updating using Kriging model

    Science.gov (United States)

    Wang, J. T.; Wang, C. J.; Zhao, J. P.

    2017-03-01

    An acceleration frequency response function (FRF) based model updating method is presented in this paper, which introduces Kriging model as metamodel into the optimization process instead of iterating the finite element analysis directly. The Kriging model is taken as a fast running model that can reduce solving time and facilitate the application of intelligent algorithms in model updating. The training samples for Kriging model are generated by the design of experiment (DOE), whose response corresponds to the difference between experimental acceleration FRFs and its counterpart of finite element model (FEM) at selected frequency points. The boundary condition is taken into account, and a two-step DOE method is proposed for reducing the number of training samples. The first step is to select the design variables from the boundary condition, and the selected variables will be passed to the second step for generating the training samples. The optimization results of the design variables are taken as the updated values of the design variables to calibrate the FEM, and then the analytical FRFs tend to coincide with the experimental FRFs. The proposed method is performed successfully on a composite structure of honeycomb sandwich beam, after model updating, the analytical acceleration FRFs have a significant improvement to match the experimental data especially when the damping ratios are adjusted.

  5. Design of Reversible Metrologic Sensor Based on Hall-effect Circuit%基于霍尔电路设计的可逆计量传感器

    Institute of Scientific and Technical Information of China (English)

    李述香; 邱召运; 张文

    2011-01-01

    In order to recognize the rotary direction and catch the reversible count information, the contrast studies of the different sampling modes based on several Hall circuit design are performed, the characteristics of the output pulse time se-quence are analyzed, and a simple design method is proposed. The assembly of switch operation Hall chip and latch operation Hall chip is adopted in the new sampling method. The rotary direction and acquisition of reversible count signal are realized in combination with the bipolar rotating magnet sampling system. The sensor circuit is composed of only two Hall circuits, with-out any external circuit. All the advantages of He'll sensor are remained. The circuit design and detailed description of the working principle and impletation method are offered in yhis paper.%以识别转向和获取可逆计数信息为主要目的,对比研究了几种基于霍尔电路设计的不同取样方式,分析了它们的输出脉冲时序特征,提出一种简单的设计方案.新的取样方式采用开关型霍尔芯片和锁存型霍尔芯片组合,配合双极旋转磁体取样系统,实现了转向识别和可逆计数信号的采集.传感器电路仅由两片霍尔电路构成,无外围电路,保留了霍尔传感器的全部优点.给出了电路设计,并详细说明了工作原理和实现方法.

  6. Comparisons organized by Ionizing Radiation Metrology Laboratory of FTMC, Lithuania.

    Science.gov (United States)

    Gudelis, A; Gorina, I

    2016-03-01

    The newly established Ionizing Radiation Metrology Laboratory of the National Metrology Institute (FTMC) in Lithuania organized four comparisons in the field of low-level radioactivity measurements in water. For gamma-ray emitters, the activity concentration in the samples was in the range 1-25Bq/kg, while for tritium it was around 2Bq/g. The assigned values of all comparisons were traceable to the primary standards of the Czech Metrology Institute (CMI).

  7. Ballistic Missile Warhead Recognition based on Micro-Doppler Frequency

    Directory of Open Access Journals (Sweden)

    Sun Hui-Xia

    2008-11-01

    Full Text Available To elucidate the spinning-precession signatures of ballistic warhead, the model of spinning precessionfor ballistic missile warhead is established and the mathematics of micro-Doppler signatures caused by spinning-precession is derived. Then the micro-Doppler features are analysed using high-resolution time-frequencytransform, and the model predictions match the experimental data well. Based on  different mass of warheadsand decoys, the feature, which can reflect the mass of the targets, is extracted from the time-frequency plane,proving a new method for recognising warheads and discriminating these from decoys. Finally the validityof the feature extracted in this study is verified by computer simulations even with low signal-to-noise ratio.Defence Science Journal, 2008, 58(6, pp.705-709, DOI:http://dx.doi.org/10.14429/dsj.58.1697

  8. Nanoionics-Based Switches for Radio-Frequency Applications

    Science.gov (United States)

    Nessel, James; Lee, Richard

    2010-01-01

    Nanoionics-based devices have shown promise as alternatives to microelectromechanical systems (MEMS) and semiconductor diode devices for switching radio-frequency (RF) signals in diverse systems. Examples of systems that utilize RF switches include phase shifters for electronically steerable phased-array antennas, multiplexers, cellular telephones and other radio transceivers, and other portable electronic devices. Semiconductor diode switches can operate at low potentials (about 1 to 3 V) and high speeds (switching times of the order of nanoseconds) but are characterized by significant insertion loss, high DC power consumption, low isolation, and generation of third-order harmonics and intermodulation distortion (IMD). MEMS-based switches feature low insertion loss (of the order of 0.2 dB), low DC power consumption (picowatts), high isolation (>30 dB), and low IMD, but contain moving parts, are not highly reliable, and must be operated at high actuation potentials (20 to 60 V) generated and applied by use of complex circuitry. In addition, fabrication of MEMS is complex, involving many processing steps. Nanoionics-based switches offer the superior RF performance and low power consumption of MEMS switches, without need for the high potentials and complex circuitry necessary for operation of MEMS switches. At the same time, nanoionics-based switches offer the high switching speed of semiconductor devices. Also, like semiconductor devices, nanoionics-based switches can be fabricated relatively inexpensively by use of conventional integrated-circuit fabrication techniques. More over, nanoionics-based switches have simple planar structures that can easily be integrated into RF power-distribution circuits.

  9. INCREASING METROLOGICAL AUTONOMY OF IN-PLANT MEASURING SYSTEMS

    Directory of Open Access Journals (Sweden)

    Mykola Mykyychuk

    2016-12-01

    Full Text Available The authors offer to solve the problem of providing traceability of measurements by increasing metrological autonomy of in-plant measuring systems. The paper shows the expedience of increasing metrological autonomy by creating a "virtual" reference. There are analysed possible variants of implementation of the "virtual" reference, which will provide high metrological stability of measurements at insignificant additional expenses. The authors point out the necessity of creation of universal technical and programmatic means of mutual comparison for the in-plant measuring systems to increase the reliability of measurements in the conditions of metrological autonomy.

  10. Frequency of damage by external hazards based on geographical information

    Energy Technology Data Exchange (ETDEWEB)

    Becker, G. [RISA Sicherheitsanalysen GmbH, Berlin (Germany); Camarinopoulos, A.; Karali, T. [ERRA, Athens (Greece); Camarinopoulos, L. [Piraeus Univ. (Greece); Schubert, B. [VENE, Hamburg (Germany)

    2013-07-01

    External explosions can significantly contribute to risk of damage for industrial plants. External explosions may origin from other plants in the neighborhood, which store and operate with explosive substances, or from transport of such substances on road, rail, or water. In all cases, some accident is a necessary condition for a hazard. Another probabilistic element is the probability of ignition. If transport causes the explosion, the location of the accident will influence the consequences. If deflagration is involved, ignition will not necessarily occur at the place of the accident, but a cloud of a combustible gas-air mixture may develop, which will ignite at some distance depending on wind velocity. In order to avoid unnecessarily pessimistic approaches, geographical information can be used in addition to local weather statistics. Geographical information systems provide map material for sites, roads, rail and rivers on a computer. This information can be used to find frequencies of damage based on numerical integration or on Monte Carlo simulation. A probabilistic model has been developed. It is based on: - A joint probability density function for wind direction and wind speed, which has been estimated from local weather statistics, - Frequency of hazards for neighboring plants and various types of traffic, - Statistics on the amounts and types of explosive materials, - The model has been implemented using one numerical integrations method and two variants of Monte Carlo method. Data has been collected and applied for a nuclear power plant in Northern Germany as an example. The method, however, can be used for any type of plant subject to external explosion hazards. In its present form, it makes use of design criteria specific for nuclear power plants, but these could be replaced by different criteria. (orig.)

  11. Frequency comb-based four-wave-mixing spectroscopy.

    Science.gov (United States)

    Lomsadze, Bachana; Cundiff, Steven T

    2017-06-15

    We experimentally demonstrate four-wave-mixing (FWM) spectroscopy using frequency combs. The experiment uses a geometry where excitation pulses and FWM signals generated by a sample co-propagate. We separate them in the radio frequency domain by heterodyne detection with a local oscillator comb that has a different repetition frequency.

  12. An iodine-based frequency reference for space applications

    Science.gov (United States)

    Schuldt, Thilo; Johann, Ulrich; Doeringshoff, Klaus; Kovalchuk, Evgeny; Peters, Achim; Braxmaier, Claus; Pahl, Julia; Stuehler, Johannes; Franz, Matthias

    We present the development of an iodine-based frequency reference for future potential applications in space, including the gravitational wave detector LISA/eLISA (Laser Interferometer Space Antenna), the mini SpaceTime Asymmetry Research (mSTAR) program, the aperture-synthesis telescope Darwin and the GRACE (Gravity Recovery and Climate Experiment) follow on mission/NGGM (Next Generation Gravity Mission) exploring Earth's gravity. Based on a state-of-the-art laboratory iodine frequency reference, setups on elegant breadboard (EBB) and engineering model (EM) level were realized, taking into account specific design criteria for space compatibility such as compactness and robustness. Both setups employ modulation transfer spectroscopy (MTS) in combination with balanced detection. They use a baseplate made of glass material in combination with a dedicated easy-to-handle assembly-integration technology (adhesive bonding) ensuring high pointing stability of the two counter-propagating laser beams in the iodine cell and therefore high long-term stability. The EBB setup utilizes a commercial off-the-shelf 30 cm long iodine cell in triple-pass configuration, the EM setup a specifically designed and manufactured compact iodine cell made of fused silica in a nine-pass configuration with a specific robust cold finger design. Both setups were characterized in beat measurements with a ULE cavity setup. Similar frequency stabilities of about 1*10 (-14) at an integration time of 1 s and below 5*10 (-15) at integration times between 10 s and 100 s were demonstrated. These values are comparable to the currently best laboratory setups. The EM setup was further subjected to environmental testing including thermal cycling and vibrational testing. Financial support by the German Space Agency DLR with funds provided by the Federal Ministry of Economics and Technology (BMWi) under grant numbers 50 QT 1102 and 50 QT 1201 is highly appreciated. The authors thank Jan Hrabina and Josef Lazar

  13. FREQUENCY-CODED OPTIMIZATION OF HOPPED-FREQUENCY PULSE SIGNAL BASED ON GENETIC ALGORITHM

    Institute of Scientific and Technical Information of China (English)

    Liu Zheng; Mu Xuehua

    2005-01-01

    The Frequency-Coded Pulse (FCP) signal has good performance of range and Doppler resolution. This paper first gives the mathematical expression of the ambiguity function for FCP signals, and then presents a coding rule for optimizing FCP signal. The genetic algorithm is presented to solve this kind of problem for optimizing codes. Finally, an example for optimizing calculation is illustrated and the optimized frequency coding results are given with the code length N=64 and N=128 respectively.

  14. Research of frequency descriptions, parameters conductometric differential sensors with pectinate topology.

    OpenAIRE

    2011-01-01

    In differential conductometric systems, for example in biosensor systems, often use co-planar thinly-pellicle structure double-sensors with pectinate topology. Simple and useful devices could be realized with help of them. But sensitivity and producibility of results those devices depends on parameters of sensors which we probe. On base of metrological research frequency descriptions, parameters conductometric differential sensors was analyzed effectiveness of using this sensors with differen...

  15. A frequency domain based rigid motion artifact reduction algorithm

    Science.gov (United States)

    Luo, Hai; Huang, Xiaojie; Pan, Wenyu; Zhou, Heqin; Feng, Huanqing

    2009-10-01

    During a CT scan, patients' conscious or unconscious motions would result in motion artifacts which undermine the image quality and hamper doctors' accurate diagnosis and therapy. It is desirable to develop a precise motion estimation and artifact reduction method in order to produce high-resolution images. Rigid motion can be decomposed into two components: translational motion and rotational motion. Since considering the rotation and translation simultaneously is very difficult, most former studies on motion artifact reduction ignore rotation. The extended HLCC based method considering the rotation and translation simultaneously relies on a searching algorithm which leads to expensive computing cost. Therefore, a novel method which does not rely on searching is desirable. In this paper, we focus on parallel-beam CT. We first propose a frequency domain based method to estimate rotational motion, which is not affected by translational motion. It realizes the separation of rotation estimation and translation estimation. Then we combine this method with the HLCC based method to construct a new method for general rigid motion called separative estimation and collective correction method. Furthermore, we present numerical simulation results to show the accuracy and robustness of our approach.

  16. Adaptive Window Zero-Crossing-Based Instantaneous Frequency Estimation

    Directory of Open Access Journals (Sweden)

    S. Chandra Sekhar

    2004-09-01

    Full Text Available We address the problem of estimating instantaneous frequency (IF of a real-valued constant amplitude time-varying sinusoid. Estimation of polynomial IF is formulated using the zero-crossings of the signal. We propose an algorithm to estimate nonpolynomial IF by local approximation using a low-order polynomial, over a short segment of the signal. This involves the choice of window length to minimize the mean square error (MSE. The optimal window length found by directly minimizing the MSE is a function of the higher-order derivatives of the IF which are not available a priori. However, an optimum solution is formulated using an adaptive window technique based on the concept of intersection of confidence intervals. The adaptive algorithm enables minimum MSE-IF (MMSE-IF estimation without requiring a priori information about the IF. Simulation results show that the adaptive window zero-crossing-based IF estimation method is superior to fixed window methods and is also better than adaptive spectrogram and adaptive Wigner-Ville distribution (WVD-based IF estimators for different signal-to-noise ratio (SNR.

  17. Image-based EUVL aberration metrology

    Science.gov (United States)

    Fenger, Germain Louis

    A significant factor in the degradation of nanolithographic image fidelity is optical wavefront aberration. As resolution of nanolithography systems increases, effects of wavefront aberrations on aerial image become more influential. The tolerance of such aberrations is governed by the requirements of features that are being imaged, often requiring lenses that can be corrected with a high degree of accuracy and precision. Resolution of lithographic systems is driven by scaling wavelength down and numerical aperture (NA) up. However, aberrations are also affected from the changes in wavelength and NA. Reduction in wavelength or increase in NA result in greater impact of aberrations, where the latter shows a quadratic dependence. Current demands in semiconductor manufacturing are constantly pushing lithographic systems to operate at the diffraction limit; hence, prompting a need to reduce all degrading effects on image properties to achieve maximum performance. Therefore, the need for highly accurate in-situ aberration measurement and correction is paramount. In this work, an approach has been developed in which several targets including phase wheel, phase disk, phase edges, and binary structures are used to generate optical images to detect and monitor aberrations in extreme ultraviolet (EUV) lithographic systems. The benefit of using printed patterns as opposed to other techniques is that the lithography system is tested under standard operating conditions. Mathematical models in conjunction with iterative lithographic simulations are used to determine pupil phase wavefront errors and describe them as combinations of Zernike polynomials.

  18. High density THz frequency comb produced by coherent synchrotron radiation

    CERN Document Server

    Tammaro, S; Roy, P; Lampin, J -F; Ducournau, G; Cuisset, A; Hindle, F; Mouret, G

    2014-01-01

    Frequency combs (FC) have radically changed the landscape of frequency metrology and high-resolution spectroscopy investigations extending tremendously the achievable resolution while increasing signal to noise ratio. Initially developed in the visible and near-IR spectral regions, the use of FC has been expanded to mid-IR, extreme ultra-violet and X-ray. Significant effort is presently dedicated to the generation of FC at THz frequencies. One solution based on converting a stabilized optical frequency comb using a photoconductive terahertz emitter, remains hampered by the low available THz power. Another approach is based on active mode locked THz quantum-cascade-lasers providing intense FC over a relatively limited spectral extension. Alternatively, here we show that dense powerful THz FC is generated over one decade of frequency by coherent synchrotron radiation (CSR). In this mode, the entire ring behaves in a similar fashion to a THz resonator wherein electron bunches emit powerful THz pulses quasi-synch...

  19. Demonstration of new frequency-based flame monitoring system

    Energy Technology Data Exchange (ETDEWEB)

    Khesin, M. [MK Engineering Inc., North Andover, MA (United States)

    1996-11-01

    Methods of flame monitoring and combustion diagnostics based on analysis of temporal frequency spectra of flame radiation are attracting growing attention. It has been demonstrated that valuable flame quality information can be extracted from the chaos of burner flames by applying advanced signal analysis. A new flame diagnostics system (Flamenco), based on the application of new signal processing algorithms, have been developed and tested. The system generates an array of statistical values correlating with main combustion parameters of individual burner flames. Along with the main system, several derivative software systems were developed to enhance the testing and analysis capabilities. This paper presents preliminary results of pilot-scale testing of the new system, conducted at a single-burner combustion test facility, with support of Forney Corporation. Pilot-scale testing was conducted on a 1.0 Mbtu/hr single-burner gas-fired boiler, equipped with analytical instrumentation to measure NOx, O{sub 2}, CO{sub 2} and CO. The tests were conducted for the full range of air flow changes at different loads. The results have proven that the new system generates output signals correlated with measured burner parameters, such as NOx and airflow. The new system offers an effective and economical new method of flame monitoring and combustion diagnostics, to facilitate balancing and adjustment of individual burners and it is applicable to both single and multi-burner installations.

  20. Wavelet-Based Speech Enhancement Using Time-Frequency Adaptation

    Directory of Open Access Journals (Sweden)

    Kun-Ching Wang

    2009-01-01

    Full Text Available Wavelet denoising is commonly used for speech enhancement because of the simplicity of its implementation. However, the conventional methods generate the presence of musical residual noise while thresholding the background noise. The unvoiced components of speech are often eliminated from this method. In this paper, a novel algorithm of wavelet coefficient threshold (WCT based on time-frequency adaptation is proposed. In addition, an unvoiced speech enhancement algorithm is also integrated into the system to improve the intelligibility of speech. The wavelet coefficient threshold (WCT of each subband is first temporally adjusted according to the value of a posterior signal-to-noise ratio (SNR. To prevent the degradation of unvoiced sounds during noise, the algorithm utilizes a simple speech/noise detector (SND and further divides speech signal into unvoiced and voiced sounds. Then, we apply appropriate wavelet thresholding according to voiced/unvoiced (V/U decision. Based on the masking properties of human auditory system, a perceptual gain factor is adopted into wavelet thresholding for suppressing musical residual noise. Simulation results show that the proposed method is capable of reducing noise with little speech degradation and the overall performance is superior to several competitive methods.

  1. Photomask Dimensional Metrology in the SEM: Has Anything Really Changed?

    Science.gov (United States)

    Postek, Michael T., Jr.; Vladar, Andras E.; Bennett, Marylyn H.

    2002-12-01

    Photomask dimensional metrology in the scanning electron microscope (SEM) has not evolved as rapidly as the metrology of resists and integrated circuit features on wafers. This has been due partly to the 4x (or 5x) reduction in the optical steppers and scanners used in the lithography process, and partly for the lesser need to account for the real three-dimensionality of the mask structures. So, where photomasks are concerned, many of the issues challenging wafer dimensional metrology at 1x are reduced by a factor of 4 or 5 and thus could be temporarily swept aside. This is rapidly changing with the introduction of advanced masks with optical proximity correction and phase shifting features used in 100 nm and smaller circuit generations. Fortunately, photomask metrology generally benefits from the advances made for wafer metrology, but there are still unique issues to be solved in this form of dimensional metrology. It is likely that no single metrology method or tool will ever provide all necessary answers. As with other types of metrology, resolution, sensitivity and linearity in the three-dimensional measurements of the shape of the lines and phase shifting features in general (width, height and wall angles) and the departures from the desired shape (surface and edge roughness, etc.) are the key parameters. Different methods and tools differ in their ability to collect averaged and localized signals with an acceptable speed, but in any case, application of this thorough knowledge of the physics of the given metrology is essential to extract the needed information. This paper will discuss the topics of precision, accuracy and traceability in the SEM metrology of photomasks. Current and possible new techniques utilized in the measurements of photomasks including charge suppression and highly accurate modeling for electron beam metrology will also be explored to answer the question "Has anything really changed?"

  2. Mid-Infrared Optical Frequency Combs based on Difference Frequency Generation for Molecular Spectroscopy

    CERN Document Server

    Cruz, Flavio C; Johnson, Todd; Ycas, Gabriel; Klose, Andrew; Giorgetta, Fabrizio R; Coddington, Ian; Diddams, Scott A

    2015-01-01

    Mid-infrared femtosecond optical frequency combs were produced by difference frequency generation of the spectral components of a near-infrared comb in a 3-mm-long MgO:PPLN crystal. We observe strong pump depletion and 9.3 dB parametric gain in the 1.5 \\mu m signal, which yields powers above 500 mW (3 \\mu W/mode) in the idler with spectra covering 2.8 \\mu m to 3.5 \\mu m. Potential for broadband, high-resolution molecular spectroscopy is demonstrated by absorption spectra and interferograms obtained by heterodyning two combs.

  3. A MEMS-based high frequency x-ray chopper.

    Science.gov (United States)

    Siria, A; Dhez, O; Schwartz, W; Torricelli, G; Comin, F; Chevrier, J

    2009-04-29

    Time-resolved x-ray experiments require intensity modulation at high frequencies (advanced rotating choppers have nowadays reached the kHz range). We here demonstrate that a silicon microlever oscillating at 13 kHz with nanometric amplitude can be used as a high frequency x-ray chopper. We claim that using micro-and nanoelectromechanical systems (MEMS and NEMS), it will be possible to achieve higher frequencies in excess of hundreds of megahertz. Working at such a frequency can open a wealth of possibilities in chemistry, biology and physics time-resolved experiments.

  4. A MEMS-based high frequency x-ray chopper

    Energy Technology Data Exchange (ETDEWEB)

    Siria, A; Schwartz, W; Chevrier, J [Institut Neel, CNRS-Universite Joseph Fourier Grenoble, BP 166, F-38042 Grenoble Cedex 9 (France); Dhez, O; Comin, F [ESRF, 6 rue Jules Horowitz, F-38043 Grenoble Cedex 9 (France); Torricelli, G [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom)

    2009-04-29

    Time-resolved x-ray experiments require intensity modulation at high frequencies (advanced rotating choppers have nowadays reached the kHz range). We here demonstrate that a silicon microlever oscillating at 13 kHz with nanometric amplitude can be used as a high frequency x-ray chopper. We claim that using micro-and nanoelectromechanical systems (MEMS and NEMS), it will be possible to achieve higher frequencies in excess of hundreds of megahertz. Working at such a frequency can open a wealth of possibilities in chemistry, biology and physics time-resolved experiments.

  5. Manufacturing and metrology for IR conformal windows and domes

    Science.gov (United States)

    Ferralli, Ian; Blalock, Todd; Brunelle, Matt; Lynch, Timothy; Myer, Brian; Medicus, Kate

    2017-05-01

    Freeform and conformal optics have the potential to dramatically improve optical systems by enabling systems with fewer optical components, reduced aberrations, and improved aerodynamic performance. These optical components differ from standard components in their surface shape, typically a non-symmetric equation based definition, and material properties. Traditional grinding and polishing tools are unable to handle these freeform shapes. Additionally, standard metrology tools cannot measure these surfaces. Desired substrates are typically hard ceramics, including poly-crystalline alumina or aluminum oxynitride. Notwithstanding the challenges that the hardness provides to manufacturing, these crystalline materials can be highly susceptible to grain decoration creating unacceptable scatter in optical systems. In this presentation, we will show progress towards addressing the unique challenges of manufacturing conformal windows and domes. Particular attention is given to our robotic polishing platform. This platform is based on an industrial robot adapted to accept a wide range of tooling and parts. The robot's flexibility has provided us an opportunity to address the unique challenges of conformal windows. Slurries and polishing active layers can easily be changed to adapt to varying materials and address grain decoration. We have the flexibility to change tool size and shape to address the varying sizes and shapes of conformal optics. In addition, the robotic platform can be a base for a deflectometry-based metrology tool to measure surface form error. This system, whose precision is independent of the robot's positioning accuracy, will allow us to measure optics in-situ saving time and reducing part risk. In conclusion, we will show examples of the conformal windows manufactured using our developed processes.

  6. SOGI-FLL Based Adaptive Filter for DSTATCOM Under Variable Supply Frequency

    Science.gov (United States)

    Puranik, Vishal; Arya, Sabha Raj

    2016-12-01

    This paper presents an adaptive filter based on second order generalized integrator-frequency locked loop (SOGI-FLL) for distribution static compensator (DSTATCOM) operating under variable supply frequency with nonlinear load. It is observed that under variable supply frequency, the FLL provides an excellent frequency tracking performance. Necessary compensation can be provided by DSTATCOM at any frequency with the help of SOGI-FLL. The MATLAB simulink model of DSTATCOM is developed with SOGI-FLL based control algorithm and rectifier based nonlinear load. This three wire system is simulated in power factor correction and zero voltage regulation mode under variable supply frequency.

  7. SOGI-FLL Based Adaptive Filter for DSTATCOM Under Variable Supply Frequency

    Science.gov (United States)

    Puranik, Vishal; Arya, Sabha Raj

    2017-08-01

    This paper presents an adaptive filter based on second order generalized integrator-frequency locked loop (SOGI-FLL) for distribution static compensator (DSTATCOM) operating under variable supply frequency with nonlinear load. It is observed that under variable supply frequency, the FLL provides an excellent frequency tracking performance. Necessary compensation can be provided by DSTATCOM at any frequency with the help of SOGI-FLL. The MATLAB simulink model of DSTATCOM is developed with SOGI-FLL based control algorithm and rectifier based nonlinear load. This three wire system is simulated in power factor correction and zero voltage regulation mode under variable supply frequency.

  8. Metrology for graphene and 2D materials

    Science.gov (United States)

    Pollard, Andrew J.

    2016-09-01

    The application of graphene, a one atom-thick honeycomb lattice of carbon atoms with superlative properties, such as electrical conductivity, thermal conductivity and strength, has already shown that it can be used to benefit metrology itself as a new quantum standard for resistance. However, there are many application areas where graphene and other 2D materials, such as molybdenum disulphide (MoS2) and hexagonal boron nitride (h-BN), may be disruptive, areas such as flexible electronics, nanocomposites, sensing and energy storage. Applying metrology to the area of graphene is now critical to enable the new, emerging global graphene commercial world and bridge the gap between academia and industry. Measurement capabilities and expertise in a wide range of scientific areas are required to address this challenge. The combined and complementary approach of varied characterisation methods for structural, chemical, electrical and other properties, will allow the real-world issues of commercialising graphene and other 2D materials to be addressed. Here, examples of metrology challenges that have been overcome through a multi-technique or new approach are discussed. Firstly, the structural characterisation of defects in both graphene and MoS2 via Raman spectroscopy is described, and how nanoscale mapping of vacancy defects in graphene is also possible using tip-enhanced Raman spectroscopy (TERS). Furthermore, the chemical characterisation and removal of polymer residue on chemical vapour deposition (CVD) grown graphene via secondary ion mass spectrometry (SIMS) is detailed, as well as the chemical characterisation of iron films used to grow large domain single-layer h-BN through CVD growth, revealing how contamination of the substrate itself plays a role in the resulting h-BN layer. In addition, the role of international standardisation in this area is described, outlining the current work ongoing in both the International Organization of Standardization (ISO) and the

  9. Quantum metrology for gravitational wave astronomy.

    Science.gov (United States)

    Schnabel, Roman; Mavalvala, Nergis; McClelland, David E; Lam, Ping K

    2010-11-16

    Einstein's general theory of relativity predicts that accelerating mass distributions produce gravitational radiation, analogous to electromagnetic radiation from accelerating charges. These gravitational waves (GWs) have not been directly detected to date, but are expected to open a new window to the Universe once the detectors, kilometre-scale laser interferometers measuring the distance between quasi-free-falling mirrors, have achieved adequate sensitivity. Recent advances in quantum metrology may now contribute to provide the required sensitivity boost. The so-called squeezed light is able to quantum entangle the high-power laser fields in the interferometer arms, and could have a key role in the realization of GW astronomy.

  10. Evaluation of metrology technologies for free form surfaces

    DEFF Research Database (Denmark)

    Arámbula, K.; Siller, H.R.; De Chiffre, Leonardo

    2012-01-01

    This research work describes a novel approach for comparing different technologies for free form surface metrology: computerized tomography (CT), photogrammetry and coordinate measuring machines (CMM). The comparison has the aim of providing relevant information for the selection of metrology...... also deals with costs issues, required standards, and necessary additional information when selecting inspection equipment....

  11. Evaluation of metrology technologies for free form surfaces

    DEFF Research Database (Denmark)

    Arámbula, K.; Siller, H.R.; De Chiffre, Leonardo

    2012-01-01

    This research work describes a novel approach for comparing different technologies for free form surface metrology: computerized tomography (CT), photogrammetry and coordinate measuring machines (CMM). The comparison has the aim of providing relevant information for the selection of metrology...... also deals with costs issues, required standards, and necessary additional information when selecting inspection equipment....

  12. Primary Laboratory for Dimentional Metrology Annual Report 2000

    DEFF Research Database (Denmark)

    De Chiffre, Leonardo; Rasmussen, Svend Nytoft

    2001-01-01

    The measurement capability concerning different areas within geometrical metrology has been maintained through approximately 1700 calibration and testing tasks for Danish clients.......The measurement capability concerning different areas within geometrical metrology has been maintained through approximately 1700 calibration and testing tasks for Danish clients....

  13. Demosaicking Based on Optimization and Projection in Different Frequency Bands

    Directory of Open Access Journals (Sweden)

    Omer OsamaA

    2008-01-01

    Full Text Available Abstract A fast and effective iterative demosaicking algorithm is described for reconstructing a full-color image from single-color filter array data. The missing color values are interpolated on the basis of optimization and projection in different frequency bands. A filter bank is used to decompose an initially interpolated image into low-frequency and high-frequency bands. In the low-frequency band, a quadratic cost function is minimized in accordance with the observation that the low-frequency components of chrominance slowly vary within an object region. In the high-frequency bands, the high-frequency components of the unknown values are projected onto the high-frequency components of the known values. Comparison of the proposed algorithm with seven state-of-the-art demosaicking algorithms showed that it outperforms all of them for 20 images on average in terms of objective quality and that it is competitive with them from the subjective quality and complexity points of view.

  14. Incident Light Frequency-Based Image Defogging Algorithm

    Directory of Open Access Journals (Sweden)

    Wenbo Zhang

    2017-01-01

    Full Text Available To solve the color distortion problem produced by the dark channel prior algorithm, an improved method for calculating transmittance of all channels, respectively, was proposed in this paper. Based on the Beer-Lambert Law, the influence between the frequency of the incident light and the transmittance was analyzed, and the ratios between each channel’s transmittance were derived. Then, in order to increase efficiency, the input image was resized to a smaller size before acquiring the refined transmittance which will be resized to the same size of original image. Finally, all the transmittances were obtained with the help of the proportion between each color channel, and then they were used to restore the defogging image. Experiments suggest that the improved algorithm can produce a much more natural result image in comparison with original algorithm, which means the problem of high color saturation was eliminated. What is more, the improved algorithm speeds up by four to nine times compared to the original algorithm.

  15. STATISTICAL APPROXIMATION BASED FINE FREQUENCY SYNCHRONIZATION FOR OFDM SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The paper proposes a novel approach for fine frequency synchronization of OFDM synchronization systems in multi-path channels. Maximum Likelihood (ML) function of frequency offsets including integral and decimal parts in frequency domain is developed according to the law of great number to eliminate the noise impact of the signal. When the timing delay close to the actual time, the proposed function produces a deep valley indicating frequency offset when large Valley-Square- Error (VSE) appears. Coarse timing offset can also be detected when function's Valley-Square-Error (VSE) is maximized. Simulation results shows that the proposed algorithm gives very robust estimation of frequency offset, and a coarse timing offset estimation.

  16. What metrology can do to improve the quality of your atmospheric ammonia measurements

    Science.gov (United States)

    Leuenberger, Daiana; Martin, Nicholas A.; Pascale, Céline; Guillevic, Myriam; Ackermann, Andreas; Ferracci, Valerio; Cassidy, Nathan; Hook, Josh; Battersby, Ross M.; Tang, Yuk S.; Stevens, Amy C. M.; Jones, Matthew R.; Braban, Christine F.; Gates, Linda; Hangartner, Markus; Sacco, Paolo; Pagani, Diego; Hoffnagle, John A.; Niederhauser, Bernhard

    2017-04-01

    . In addition, an SI-traceable dilution system based on a cascade of critical orifices has been established to dilute NH3 mixtures in the order of μmol/mol stored in cylinders. It is planned to apply this system to calibrate and re-sample gas mixtures in cylinders due to its very economical gas use. Here we present insights into the development of said infrastructure and results performance tests. Moreover, we include results of the study on adsorption/desorption effects in dry as well as humidified matrix gas into the discussion on the generation of reference gas mixtures. Acknowledgement: This work was supported by the European Metrology Research Programme (EMRP). The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union.

  17. A curved edge diffraction-utilized displacement sensor for spindle metrology

    Science.gov (United States)

    Lee, ChaBum; Mahajan, Satish M.; Zhao, Rui; Jeon, Seongkyul

    2016-07-01

    This paper presents a new dimensional metrological sensing principle for a curved surface based on curved edge diffraction. Spindle error measurement technology utilizes a cylindrical or spherical target artifact attached to the spindle with non-contact sensors, typically a capacitive sensor (CS) or an eddy current sensor, pointed at the artifact. However, these sensors are designed for flat surface measurement. Therefore, measuring a target with a curved surface causes error. This is due to electric fields behaving differently between a flat and curved surface than between two flat surfaces. In this study, a laser is positioned incident to the cylindrical surface of the spindle, and a photodetector collects the total field produced by the diffraction around the target surface. The proposed sensor was compared with a CS within a range of 500 μm. The discrepancy between the proposed sensor and CS was 0.017% of the full range. Its sensing performance showed a resolution of 14 nm and a drift of less than 10 nm for 7 min of operation. This sensor was also used to measure dynamic characteristics of the spindle system (natural frequency 181.8 Hz, damping ratio 0.042) and spindle runout (22.0 μm at 2000 rpm). The combined standard uncertainty was estimated as 85.9 nm under current experiment conditions. It is anticipated that this measurement technique allows for in situ health monitoring of a precision spindle system in an accurate, convenient, and low cost manner.

  18. Dimensional metrology of smooth micro structures utilizing the spatial modulation of white-light interference fringes

    Science.gov (United States)

    Zhou, Yi; Tang, Yan; Deng, Qinyuan; Liu, Junbo; Wang, Jian; Zhao, Lixin

    2017-08-01

    Dimensional metrology for micro structure plays an important role in addressing quality issues and observing the performance of micro-fabricated products. In white light interferometry, the proposed method is expected to measure three-dimensional topography through modulation depth in spatial frequency domain. A normalized modulation depth is first obtained in the xy plane (image plane) for each CCD image individually. After that, the modulation depth of each pixel is analyzed along the scanning direction (z-axis) to reshape the topography of micro samples. Owing to the characteristics of modulation depth in broadband light interferometry, the method could effectively suppress the negative influences caused by light fluctuations and external irradiance disturbance. Both theory and experiments are elaborated in detail to verify that the modulation depth-based method can greatly level up the stability and sensitivity with satisfied precision in the measurement system. This technique can achieve an improved robustness in a complex measurement environment with the potential to be applied in online topography measurement such as chemistry and medical domains.

  19. A curved edge diffraction-utilized displacement sensor for spindle metrology.

    Science.gov (United States)

    Lee, ChaBum; Mahajan, Satish M; Zhao, Rui; Jeon, Seongkyul

    2016-07-01

    This paper presents a new dimensional metrological sensing principle for a curved surface based on curved edge diffraction. Spindle error measurement technology utilizes a cylindrical or spherical target artifact attached to the spindle with non-contact sensors, typically a capacitive sensor (CS) or an eddy current sensor, pointed at the artifact. However, these sensors are designed for flat surface measurement. Therefore, measuring a target with a curved surface causes error. This is due to electric fields behaving differently between a flat and curved surface than between two flat surfaces. In this study, a laser is positioned incident to the cylindrical surface of the spindle, and a photodetector collects the total field produced by the diffraction around the target surface. The proposed sensor was compared with a CS within a range of 500 μm. The discrepancy between the proposed sensor and CS was 0.017% of the full range. Its sensing performance showed a resolution of 14 nm and a drift of less than 10 nm for 7 min of operation. This sensor was also used to measure dynamic characteristics of the spindle system (natural frequency 181.8 Hz, damping ratio 0.042) and spindle runout (22.0 μm at 2000 rpm). The combined standard uncertainty was estimated as 85.9 nm under current experiment conditions. It is anticipated that this measurement technique allows for in situ health monitoring of a precision spindle system in an accurate, convenient, and low cost manner.

  20. Challenges in LER/CDU metrology in DSA: placement error and cross-line correlations

    Science.gov (United States)

    Constantoudis, Vassilios; Kuppuswamy, Vijaya-Kumar M.; Gogolides, Evangelos; Pret, Alessandro V.; Pathangi, Hari; Gronheid, Roel

    2016-03-01

    DSA lithography poses new challenges in LER/LWR metrology due to its self-organized and pitch-based nature. To cope with these challenges, a novel characterization approach with new metrics and updating the older ones is required. To this end, we focus on two specific challenges of DSA line patterns: a) the large correlations between the left and right edges of a line (line wiggling, rms(LWR)frequency part is related to the local placement errors of device structures. For the second, we propose the c-factor correlation function which quantifies the strength of the correlations between lines versus their horizontal distance in pitches. Also, we define roughness and uniformity parameters for the pitch changes along and across lines. The proposed characterization approach is applied to the analysis of line/space patterns obtained with the Liu-Nealey (LiNe) flow (post PMMA removal and pattern transfer) revealing the effects of pattern transfer on roughness and uniformity. Finally, we calculate the cfactor function of various Next-Generation Lithography techniques and reveal their distinct footprint on the extent of cross-line correlations.

  1. Capacitance-Based Frequency Adjustment of Micro Piezoelectric Vibration Generator

    Directory of Open Access Journals (Sweden)

    Xinhua Mao

    2014-01-01

    Full Text Available Micro piezoelectric vibration generator has a wide application in the field of microelectronics. Its natural frequency is unchanged after being manufactured. However, resonance cannot occur when the natural frequencies of a piezoelectric generator and the source of vibration frequency are not consistent. Output voltage of the piezoelectric generator will sharply decline. It cannot normally supply power for electronic devices. In order to make the natural frequency of the generator approach the frequency of vibration source, the capacitance FM technology is adopted in this paper. Different capacitance FM schemes are designed by different locations of the adjustment layer. The corresponding capacitance FM models have been established. Characteristic and effect of the capacitance FM have been simulated by the FM model. Experimental results show that the natural frequency of the generator could vary from 46.5 Hz to 42.4 Hz when the bypass capacitance value increases from 0 nF to 30 nF. The natural frequency of a piezoelectric vibration generator could be continuously adjusted by this method.

  2. Optical metrology tools for the Virgo projet

    Science.gov (United States)

    Loriette, V.

    For more than thirty years the search for gravitationnal waves, predicted by Einstein's relativistic theory of gravitation, has been an intense research field in experimental as well as theoretical physics. Today, with the constant advance of technology in optics, lasers, data analysis and processing, ... a promising way of directly detecting gravitationnal waves with earth-based instruments is optical interferometry. Before the end of this century many experiments will be carried on in Australia, Europe, Japan and the United States to detect the passage of a gravitationnal wave through giant Michelson-type interferometers. The effects predicted are so small, (a gravitationnal wave changes the length of three kilometer long arms by one thousandth of a fermi) that the need for “perfect” optical components is a key to the success of these experiments. Still a few years ago it would have been impossible to make optical components that would satisfy the required specifications for such interferometric detectors. For nearly ten years constant R&D efforts in optical coating manufacturing, optical material fabrication and optical metrology, allow us today to make such components. This text is intended to describe the field of optical metrology as it is needed for the testing of optical parts having performances far beyond than everything previously made. The first chapter is an introduction to gravitationnal waves, their sources and their effects on detectors. Starting by newtonian mechanics we jump rapidly to the general theory of relativity and describe particular solutions of Einstein's equations in the case of weak gravitationnal fields, which are periodic perturbations of the space-time metric in the form of plane waves, the so-called gravitationnal waves. We present various candidate sources, terrestrial and extra-terrestrial and give a short description of the two families of detectors: resonnant bars and optical interferometers. The second part of this chapter

  3. Overlay mark optimization for thick-film resist overlay metrology

    Institute of Scientific and Technical Information of China (English)

    Zhu Liang; Li Jie; Zhou Congshu; Gu Yili; Yang Huayue

    2009-01-01

    For thick resist implant layers, such as a high voltage P well and a deep N well, systematic and uncorrectable overlay residues brought about by the tapered resist profiles were found. It was found that the tapered profile is closely related to the pattern density. Potential solutions of the manufacturing problem include hardening the film solidness or balancing the exposure density. In this paper, instead of focusing on the process change methodology,we intend to solve the issue of the overlay metrology error from the perspective of the overlay mark design. Based on the comparison of the overlay performances between the proposed overlay mark and the original design, it is shown that the optimized overlay mark target achieves better performance in terms of profiles, dynamic precision,tool induced shift (TIS), and residues. Furthermore, five types of overlay marks with dummy bars are studied, and a recommendation for the overlay marks is given.

  4. Surface Figure Metrology for CELT Primary Mirror Segments

    Energy Technology Data Exchange (ETDEWEB)

    Sommargren, G; Phillion, D; Seppala, L; Lerner, S

    2001-02-27

    The University of California and California Institute of Technology are currently studying the feasibility of building a 30-m segmented ground based optical telescope called the California Extremely Large Telescope (CELT). The early ideas for this telescope were first described by Nelson and Mast and more recently refined by Nelson. In parallel, concepts for the fabrication of the primary segments were proposed by Mast, Nelson and Sommargren where high risk technologies were identified. One of these was the surface figure metrology needed for fabricating the aspheric mirror segments. This report addresses the advanced interferometry that will be needed to achieve 15nm rms accuracy for mirror segments with aspheric departures as large as 35mm peak-to-valley. For reasons of cost, size, measurement consistency and ease of operation we believe it is desirable to have a single interferometer that can be universally applied to each and every mirror segment. Such an instrument is described in this report.

  5. Integrated metrology: an enabler for advanced process control (APC)

    Science.gov (United States)

    Schneider, Claus; Pfitzner, Lothar; Ryssel, Heiner

    2001-04-01

    Advanced process control (APC) techniques become more and more important as short innovation cycles in microelectronics and a highly competitive market requires cost-effective solutions in semiconductor manufacturing. APC marks a paradigm shift from statistically based techniques (SPC) using monitor wafers for sampling measurement data towards product wafer control. The APC functionalities including run-to-run control, fault detection, and fault analysis allow to detect process drifts and excursions at an early stage and to minimize the number of misprocessed wafers. APC is being established as part of factory control systems through the definition of an APC framework. A precondition for APC is the availability of sensors and measurement methods providing the necessary wafer data. This paper discusses integrated metrology as an enabler for APC and demonstrates practical implementations in semiconductor manufacturing.

  6. An Efficient Frequency Recognition Method Based on Likelihood Ratio Test for SSVEP-Based BCI

    Directory of Open Access Journals (Sweden)

    Yangsong Zhang

    2014-01-01

    Full Text Available An efficient frequency recognition method is very important for SSVEP-based BCI systems to improve the information transfer rate (ITR. To address this aspect, for the first time, likelihood ratio test (LRT was utilized to propose a novel multichannel frequency recognition method for SSVEP data. The essence of this new method is to calculate the association between multichannel EEG signals and the reference signals which were constructed according to the stimulus frequency with LRT. For the simulation and real SSVEP data, the proposed method yielded higher recognition accuracy with shorter time window length and was more robust against noise in comparison with the popular canonical correlation analysis- (CCA- based method and the least absolute shrinkage and selection operator- (LASSO- based method. The recognition accuracy and information transfer rate (ITR obtained by the proposed method was higher than those of the CCA-based method and LASSO-based method. The superior results indicate that the LRT method is a promising candidate for reliable frequency recognition in future SSVEP-BCI.

  7. Quantum metrology with unitary parametrization processes.

    Science.gov (United States)

    Liu, Jing; Jing, Xiao-Xing; Wang, Xiaoguang

    2015-02-24

    Quantum Fisher information is a central quantity in quantum metrology. We discuss an alternative representation of quantum Fisher information for unitary parametrization processes. In this representation, all information of parametrization transformation, i.e., the entire dynamical information, is totally involved in a Hermitian operator H. Utilizing this representation, quantum Fisher information is only determined by H and the initial state. Furthermore, H can be expressed in an expanded form. The highlights of this form is that it can bring great convenience during the calculation for the Hamiltonians owning recursive commutations with their partial derivative. We apply this representation in a collective spin system and show the specific expression of H. For a simple case, a spin-half system, the quantum Fisher information is given and the optimal states to access maximum quantum Fisher information are found. Moreover, for an exponential form initial state, an analytical expression of quantum Fisher information by H operator is provided. The multiparameter quantum metrology is also considered and discussed utilizing this representation.

  8. MAMMUT: mirror vibration metrology for VLTI

    Science.gov (United States)

    Spaleniak, Izabela; Giessler, Frank; Geiss, Reinhard; Minardi, Stefano; Pertsch, Thomas; Neuhaeuser, Ralph; Becker, Martin; Rothhardt, Manfred; Delplancke, Françoise; Richichi, Andrea; Ménardi, Serge; Schmid, Christian

    2010-07-01

    MAMMUT (Mirror vibrAtion Metrolology systeM for the Unit Telescope) is an ESO funded feasibility project for the development of a fiber interferometer prototype designed for optical path laser-metrology along the optical train of the Unit Telescopes (UT) of the Very Large Telescope Interferometer (VLTI). Fast mechanical vibrations originating in the VLTI cause fast variations of the optical path difference between two arms of the stellar interferometer, thus reducing the contrast of measured interference fringes. MAMMUT aims at monitoring in real time the optical path variations inside the Coudé train of the UT, for active control purposes. MAMMUT features a 250-meter-long optical fiber which can be used to deliver and inject a laser beam at 1353 nm into the UT. The injected beam can be dropped from the telescope in the Coudé room and interfered with a phase reference, provided by the second 250-meter-long arm of the fiber interferometer. The optical path variations are measured by means of an active homodyne scheme. Coherence between the beam at the injection point and the phase reference is provided by active fiber stabilization, made possible by the implementation of an internal metrology channel in MAMMUT. Here we present the initial laboratory performance results of the MAMMUT prototype, which will be able to sense optical path variations of +/- 5 μm with sub-10 nm precision within a bandwidth of at least 100 Hz.

  9. Three-dimensional metrology inside a vacuum chamber

    Science.gov (United States)

    Costille, Anne; Beaumont, Florent; Prieto, Eric; Carle, Michael; Fabron, Christophe

    2016-07-01

    Several three dimensional coordinates systems are proposed by companies to provide accurate measurement of mechanical parts in a volume. None of them are designed to perform the metrology of a system in a vacuum chamber. In the frame of the test of NISP instrument from ESA Euclid mission, the question was raised to perform a three dimensional measurement of different parts during the thermal test of NISP instrument into ERIOS chamber done at Laboratoire d'Astrophysique de Marseille (LAM). One of the main objectives of the test campaign will be the measurement of the focus position of NISP image plane with respect to the EUCLID object plane to ensure a good focalisation of NISP instrument after integration on the payload. A Metrology Verification System (MVS) has been proposed. Its goal is to provide at operational temperature the measurement of references frames set on a EUCLID telescope simulator and NISP, the knowledge of the coordinates of the object point source provided by the telescope simulator and the measurement of the angle between the telescope simulator optical axis and NISP optical axis. The MVS concept is based on the use of a laser tracker, outside the vacuum chamber, that measures reflectors inside the vacuum chamber through a curved window. We will present preliminary results that show the possibility to perform this type of measurements and the accuracy reached in this configuration. An analysis of the contributors to the measurement error budget of the MVS is proposed, based on the current knowledge of the MVS performance and constraints during the TB/TV tests.

  10. Quantum frequency doubling based on tripartite entanglement with cavities

    Science.gov (United States)

    Juan, Guo; Zhi-Feng, Wei; Su-Ying, Zhang

    2016-02-01

    We analyze the entanglement characteristics of three harmonic modes, which are the output fields from three cavities with an input tripartite entangled state at fundamental frequency. The entanglement properties of the input beams can be maintained after their frequencies have been up-converted by the process of second harmonic generation. We have calculated the parametric dependences of the correlation spectrum on the initial squeezing factor, the pump power, the transmission coefficient, and the normalized analysis frequency of cavity. The numerical results provide references to choose proper experimental parameters for designing the experiment. The frequency conversion of the multipartite entangled state can also be applied to a quantum communication network. Project supported by the National Natural Science Foundation of China (Grant No. 91430109), the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20111401110004), and the Natural Science Foundation of Shanxi Province, China (Grant No. 2014011005-3).

  11. A Preamble-Based Frequency Offset Compensation Scheme in Multiple Input Multiple Output Orthogonal Frequency Division Multiplexing Systems

    Directory of Open Access Journals (Sweden)

    Elnaz Ershadi

    2010-01-01

    Full Text Available Problem statement: Combining the properties of Multiple Input Multiple Output (MIMO systems with those of Orthogonal Frequency Division Multiplexing (OFDM, MIMO-OFDM was considered to be a promising technique in the future of wireless communications. However, its sensitivity to frequency offsets which results in Inter-Carrier Interferences (ICIs makes it necessary to use an exact frequency offset estimation method for data recovery in the MIMO-OFDM receiver. Approach: In this study, a new preamble-based frequency offset compensation method was introduced in frequency domain. In each block, two preambles are used to initially obtain the channel coefficients through LS channel estimation method. A polynomial curve fitting algorithm was then applied so that the frequency offsets experienced by every single data subcarrier are separately determined. Finally, to improve the compensating process, an iterative algorithm was applied. Results: Simulation results clearly showed that our proposed method was accurate in multipath fading channels and precisely recovered the transmitted data symbols. The BER performance of the iterative algorithm is within an acceptable distance of that in the ideal channel. Conclusion: In comparison with the conventional methods, our proposed scheme was less complex and showed better performance in lower SNRs. For further research, it can be investigated and improved while considering correlated antennas and spatial multiplexing.

  12. Fundamental Performance Determining Factors of the Ultrahigh-Precision Space-Borne Optical Metrology System for the LISA Pathfinder mission

    CERN Document Server

    Hechenblaikner, Gerald

    2013-01-01

    The LISA Pathfinder mission to space employs an optical metrology system (OMS) at its core to measure the distance and attitude between two freely floating test-masses to picometer and nanorad accuracy, respectively, within the measurement band of [1 mHz, 30 mHz]. The OMS is based upon an ultra-stable optical bench with 4 heterodyne interferometers from which interference signals are read-out and processed by a digital phase-meter. Laser frequency noise, power fluctuations and optical path-length variations are suppressed to uncritical levels by dedicated control loops so that the measurement performance approaches the sensor limit imposed by the phase-meter. The system design is such that low frequency common mode noise which affects the read-out phase of all four interferometers is generally well suppressed by subtraction of a reference phase from the other interferometer signals. However, high frequency noise directly affects measurement performance and its common mode rejection depends strongly on the rel...

  13. Frequency Response Function Based Damage Identification for Aerospace Structures

    Science.gov (United States)

    Oliver, Joseph Acton

    Structural health monitoring technologies continue to be pursued for aerospace structures in the interests of increased safety and, when combined with health prognosis, efficiency in life-cycle management. The current dissertation develops and validates damage identification technology as a critical component for structural health monitoring of aerospace structures and, in particular, composite unmanned aerial vehicles. The primary innovation is a statistical least-squares damage identification algorithm based in concepts of parameter estimation and model update. The algorithm uses frequency response function based residual force vectors derived from distributed vibration measurements to update a structural finite element model through statistically weighted least-squares minimization producing location and quantification of the damage, estimation uncertainty, and an updated model. Advantages compared to other approaches include robust applicability to systems which are heavily damped, large, and noisy, with a relatively low number of distributed measurement points compared to the number of analytical degrees-of-freedom of an associated analytical structural model (e.g., modal finite element model). Motivation, research objectives, and a dissertation summary are discussed in Chapter 1 followed by a literature review in Chapter 2. Chapter 3 gives background theory and the damage identification algorithm derivation followed by a study of fundamental algorithm behavior on a two degree-of-freedom mass-spring system with generalized damping. Chapter 4 investigates the impact of noise then successfully proves the algorithm against competing methods using an analytical eight degree-of-freedom mass-spring system with non-proportional structural damping. Chapter 5 extends use of the algorithm to finite element models, including solutions for numerical issues, approaches for modeling damping approximately in reduced coordinates, and analytical validation using a composite

  14. State preparation for quantum information science and metrology

    Energy Technology Data Exchange (ETDEWEB)

    Samblowski, Aiko

    2012-06-08

    The precise preparation of non-classical states of light is a basic requirement for performing quantum information tasks and quantum metrology. Depending on the assignment, the range of required states varies from preparing and modifying squeezed states to generating bipartite entanglement and establishing multimode entanglement networks. Every state needs special preparation techniques and hence it is important to develop the experimental expertise to generate all states with the desired degree of accuracy. In this thesis, the experimental preparation of different kinds of non-classical states of light is demonstrated. Starting with a multimode entangled state, the preparation of an unconditionally generated bound entangled state of light of unprecedented accuracy is shown. Its existence is of fundamental interest, since it certifies an intrinsic irreversibility of entanglement and suggests a connection with thermodynamics. The state is created in a network of linear optics, utilizing optical parametric amplifiers, operated below threshold, beam splitters and phase gates. The experimental platform developed here afforded the precise and stable control of all experimental parameters. Focusing on the aspect of quantum information networks, the generation of suitable bipartite entangled states of light is desirable. The optical connection between atomic transitions and light that can be transmitted via telecommunications fibers opens the possibility to employ quantum memories within fiber networks. For this purpose, a non-degenerate optical parametric oscillator is operated above threshold and the generation of bright bipartite entanglement between its twin beams at the wavelengths of 810 nm and 1550 nm is demonstrated. In the field of metrology, quantum states are used to enhance the measurement precision of interferometric gravitational wave (GW) detectors. Recently, the sensitivity of a GW detector operated at a wavelength of 1064 nm was increased using squeezed

  15. Entanglement and Metrology with Singlet-Triplet Qubits

    Science.gov (United States)

    Shulman, Michael Dean

    Electron spins confined in semiconductor quantum dots are emerging as a promising system to study quantum information science and to perform sensitive metrology. Their weak interaction with the environment leads to long coherence times and robust storage for quantum information, and the intrinsic tunability of semiconductors allows for controllable operations, initialization, and readout of their quantum state. These spin qubits are also promising candidates for the building block for a scalable quantum information processor due to their prospects for scalability and miniaturization. However, several obstacles limit the performance of quantum information experiments in these systems. For example, the weak coupling to the environment makes inter-qubit operations challenging, and a fluctuating nuclear magnetic field limits the performance of single-qubit operations. The focus of this thesis will be several experiments which address some of the outstanding problems in semiconductor spin qubits, in particular, singlet-triplet (S-T0) qubits. We use these qubits to probe both the electric field and magnetic field noise that limit the performance of these qubits. The magnetic noise bath is probed with high bandwidth and precision using novel techniques borrowed from the field of Hamiltonian learning, which are effective due to the rapid control and readout available in S-T 0 qubits. These findings allow us to effectively undo the undesired effects of the fluctuating nuclear magnetic field by tracking them in real-time, and we demonstrate a 30-fold improvement in the coherence time T2*. We probe the voltage noise environment of the qubit using coherent qubit oscillations, which is partially enabled by control of the nuclear magnetic field. We find that the voltage noise bath is frequency-dependent, even at frequencies as high as 1MHz, and it shows surprising and, as of yet, unexplained temperature dependence. We leverage this knowledge of the voltage noise environment, the

  16. High-resolution and wide-bandwidth light intensity fiber optic displacement sensor for MEMS metrology.

    Science.gov (United States)

    Orłowska, Karolina; Świątkowski, Michał; Kunicki, Piotr; Kopiec, Daniel; Gotszalk, Teodor

    2016-08-01

    We report on the design, properties, and applications of a high-resolution and wide-bandwidth light intensity fiber optic displacement sensor for microelectromechanical system (MEMS) metrology. There are two types of structures that the system is dedicated to: vibrating with both high and low frequencies. In order to ensure high-frequency and high-resolution measurements, frequency down mixing and selective signal processing were applied. The obtained effective measuring bandwidth ranges from single hertz to 1 megahertz. The achieved resolution presented here is 116  pm/Hz1/2 and 138  pm/Hz1/2 for low-frequency and high-frequency operation modes, respectively, whereas the measurement of static displacement is 100 μm.

  17. Optimal adaptive control for quantum metrology with time-dependent Hamiltonians

    Science.gov (United States)

    Pang, Shengshi; Jordan, Andrew N.

    2017-01-01

    Quantum metrology has been studied for a wide range of systems with time-independent Hamiltonians. For systems with time-dependent Hamiltonians, however, due to the complexity of dynamics, little has been known about quantum metrology. Here we investigate quantum metrology with time-dependent Hamiltonians to bridge this gap. We obtain the optimal quantum Fisher information for parameters in time-dependent Hamiltonians, and show proper Hamiltonian control is generally necessary to optimize the Fisher information. We derive the optimal Hamiltonian control, which is generally adaptive, and the measurement scheme to attain the optimal Fisher information. In a minimal example of a qubit in a rotating magnetic field, we find a surprising result that the fundamental limit of T2 time scaling of quantum Fisher information can be broken with time-dependent Hamiltonians, which reaches T4 in estimating the rotation frequency of the field. We conclude by considering level crossings in the derivatives of the Hamiltonians, and point out additional control is necessary for that case. PMID:28276428

  18. 3D spectral imaging system for anterior chamber metrology

    Science.gov (United States)

    Anderson, Trevor; Segref, Armin; Frisken, Grant; Frisken, Steven

    2015-03-01

    Accurate metrology of the anterior chamber of the eye is useful for a number of diagnostic and clinical applications. In particular, accurate corneal topography and corneal thickness data is desirable for fitting contact lenses, screening for diseases and monitoring corneal changes. Anterior OCT systems can be used to measure anterior chamber surfaces, however accurate curvature measurements for single point scanning systems are known to be very sensitive to patient movement. To overcome this problem we have developed a parallel 3D spectral metrology system that captures simultaneous A-scans on a 2D lateral grid. This approach enables estimates of the elevation and curvature of anterior and posterior corneal surfaces that are robust to sample movement. Furthermore, multiple simultaneous surface measurements greatly improve the ability to register consecutive frames and enable aggregate measurements over a finer lateral grid. A key element of our approach has been to exploit standard low cost optical components including lenslet arrays and a 2D sensor to provide a path towards low cost implementation. We demonstrate first prototypes based on 6 Mpixel sensor using a 250 μm pitch lenslet array with 300 sample beams to achieve an RMS elevation accuracy of 1μm with 95 dB sensitivity and a 7.0 mm range. Initial tests on Porcine eyes, model eyes and calibration spheres demonstrate the validity of the concept. With the next iteration of designs we expect to be able to achieve over 1000 simultaneous A-scans in excess of 75 frames per second.

  19. Metrology in physics, chemistry, and biology: differing perceptions.

    Science.gov (United States)

    Iyengar, Venkatesh

    2007-04-01

    The association of physics and chemistry with metrology (the science of measurements) is well documented. For practical purposes, basic metrological measurements in physics are governed by two components, namely, the measure (i.e., the unit of measurement) and the measurand (i.e., the entity measured), which fully account for the integrity of a measurement process. In simple words, in the case of measuring the length of a room (the measurand), the SI unit meter (the measure) provides a direct answer sustained by metrological concepts. Metrology in chemistry, as observed through physical chemistry (measures used to express molar relationships, volume, pressure, temperature, surface tension, among others) follows the same principles of metrology as in physics. The same basis percolates to classical analytical chemistry (gravimetry for preparing high-purity standards, related definitive analytical techniques, among others). However, certain transition takes place in extending the metrological principles to chemical measurements in complex chemical matrices (e.g., food samples), as it adds a third component, namely, indirect measurements (e.g., AAS determination of Zn in foods). This is a practice frequently used in field assays, and calls for additional steps to account for traceability of such chemical measurements for safeguarding reliability concerns. Hence, the assessment that chemical metrology is still evolving.

  20. High resolution mid-infrared spectroscopy based on frequency upconversion

    DEFF Research Database (Denmark)

    Dam, Jeppe Seidelin; Hu, Qi; Tidemand-Lichtenberg, Peter

    2013-01-01

    We present high resolution upconversion of incoherent infrared radiation by means of sum-frequency mixing with a laser followed by simple CCD Si-camera detection. Noise associated with upconversion is, in strong contrast to room temperature direct mid-IR detection, extremely small, thus very faint...... signals can be analyzed. The obtainable frequency resolution is usually in the nm range where sub nm resolution is preferred in many applications, like gas spectroscopy. In this work we demonstrate how to obtain sub nm resolution when using upconversion. In the presented realization one object point...

  1. Laser frequency locking based on Rydberg electromagnetically induced transparency

    Science.gov (United States)

    Yuechun, Jiao; Jingkui, Li; Limei, Wang; Hao, Zhang; Linjie, Zhang; Jianming, Zhao; Suotang, Jia

    2016-05-01

    We present a laser frequency locking to Rydberg transition with electromagnetically induced transparency (EIT) spectra in a room-temperature cesium vapor cell. Cesium levels 6S1/2, 6P3/2, and the nD5/2 state, compose a cascade three-level system, where a coupling laser drives Rydberg transition, and probe laser detects the EIT signal. The error signal, obtained by demodulating the EIT signal, is used to lock the coupling laser frequency to Rydberg transition. The laser frequency fluctuation, ˜0.7 MHz, is obtained after locking on, with the minimum Allan variance to be 8.9 × 10-11. This kind of locking method can be used to stabilize the laser frequency to the excited transition. Project supported by the National Basic Research Program of China (Grant No. 2012CB921603), the National Natural Science Foundation of China (Grants Nos. 11274209, 61475090, 61378039, and 61378013), and the Research Project Supported by Shanxi Scholarship Council of China (Grant No. 2014-009).

  2. Radio frequency power sensor based on MEMS technology

    NARCIS (Netherlands)

    Fernandez, L.J.; Visser, Eelke; Sesé, J.; Wiegerink, Remco J.; Jansen, Henricus V.; Flokstra, Jan; Flokstra, Jakob; Elwenspoek, Michael Curt

    2003-01-01

    We present the first measurement results of a power sensor for radio frequency (rf) signals (50 kHz - 40 GHz) with almost no dissipation during the measurement. This sensor is, therefore, a 'through' power sensor, that means that the rf signal is available during the measurement of its power. The

  3. Parametric adaptive time-frequency representation based on time-sheared Gabor atoms

    Institute of Scientific and Technical Information of China (English)

    Ma Shiwei; Zhu Xiaojin; Chen Guanghua; Wang Jian; Cao Jialin

    2007-01-01

    A localized parametric time-sheared Gabor atom is derived by convolving a linear frequency modulated factor, modulating in frequency and translating in time to a dilated Gaussian function, which is the generalization of Gabor atom and is more delicate for matching most of the signals encountered in practice, especially for those having frequency dispersion characteristics. The time-frequency distribution of this atom concentrates in its time center and frequency center along energy curve, with the curve being oblique to a certain extent along the time axis. A novel parametric adaptive time-frequency distribution based on a set of the derived atoms is then proposed using a adaptive signal subspace decomposition method in frequency domain, which is non-negative time-frequency energy distribution and free of cross-term interference for multicomponent signals. The results of numerical simulation manifest the effectiveness of the approach in time-frequency representation and signal de-noising processing.

  4. Volumetric rendering and metrology of spherical gradient refractive index lens imaged by angular scan optical coherence tomography system.

    Science.gov (United States)

    Yao, Jianing; Thompson, Kevin P; Ma, Bin; Ponting, Michael; Rolland, Jannick P

    2016-08-22

    In this paper, we develop the methodology, including the refraction correction, geometrical thickness correction, coordinate transformation, and layer segmentation algorithms, for 3D rendering and metrology of a layered spherical gradient refractive index (S-GRIN) lens based on the imaging data collected by an angular scan optical coherence tomography (OCT) system. The 3D mapping and rendering enables direct 3D visualization and internal defect inspection of the lens. The metrology provides assessment of the surface geometry, the lens thickness, the radii of curvature of the internal layer interfaces, and the misalignment of the internal S-GRIN distribution with respect to the lens surface. The OCT metrology results identify the manufacturing defects, and enable targeted process development for optimizing the manufacturing parameters. The newly fabricated S-GRIN lenses show up to a 7x spherical aberration reduction that allows a significantly increased utilizable effective aperture.

  5. Ionising radiation metrology for the metallurgical industry

    Directory of Open Access Journals (Sweden)

    García-Toraño E.

    2014-01-01

    Full Text Available Every year millions tons of steel are produced worldwide from recycled scrap loads. Although the detection systems in the steelworks prevent most orphan radioactive sources from entering the furnace, there is still the possibility of accidentally melting a radioactive source. The MetroMetal project, carried out in the frame of the European Metrology Research Programme (EMRP, addresses this problem by studying the existing measurement systems, developing sets of reference sources in various matrices (cast steel, slag, fume dust and proposing new detection instruments. This paper presents the key lines of the project and describes the preparation of radioactive sources as well as the intercomparison exercises used to test the calibration and correction methods proposed within the project.

  6. Traceability and uncertainty estimation in coordinate metrology

    DEFF Research Database (Denmark)

    Hansen, Hans Nørgaard; Savio, Enrico; De Chiffre, Leonardo

    2001-01-01

    National and international standards have defined performance verification procedures for coordinate measuring machines (CMMs) that typically involve their ability to measure calibrated lengths and to a certain extent form. It is recognised that, without further analysis or testing, these results...... are insufficient to determine the task specific uncertainty of most measurements. Therefore, performance verification methods defined in current standards do not guarantee traceability of measurements performed with a CMM for all measurement tasks, and procedures for the assessment of task-related uncertainties...... are required. Depending on the requirements for uncertainty level, different approaches may be adopted to achieve traceability. Especially in the case of complex measurement situations and workpieces the procedures are not trivial. This paper discusses the establishment of traceability in coordinate metrology...

  7. UPWIND 1A2 Metrology. Final Report

    DEFF Research Database (Denmark)

    Eecen, P.J.; Wagenaar, J.W.; Stefanatos, N.

    The UpWind project is a European research project that focuses on the necessary up-scaling of wind energy in 2020. Among the problems that hinder the development of wind energy are measurement problems. For example: to experimentally confirm a theoretical improvement in energy production of a few...... percent of a new design by field experiments is very hard to almost impossible. As long as convincing field tests have not confirmed the actual improvement, the industry will not invest much to change the turbine design. This is an example that clarifies why the development of wind energy is hindered...... by metrology problems (measurement problems). Other examples are in the fields of: • Warranty performance measurements • Improvement of aerodynamic codes • Assessment of wind resources In general terms the uncertainties of the testing techniques and methods are typically much higher than the requirements...

  8. Metrology in arc plasmas - A new cathode

    Science.gov (United States)

    Croche, R.

    1980-02-01

    A new radiating source consisting of an electric arc under argon pressure is described, with power varying between about 0.2 and 1.5 kW, and with the plasma furnishing a continuous spectrum between 115 and 350 nm. The arc functions from 5 to 50 A, with a voltage varying between 30 and 35 V. The cathode of the transfer arc is described in detail, including such advantages as easy igniting of the arc and the possibility of re-sharpening the tip of the cathode. Most important, the new 'knife-shaped' form of the tungsten cathode has improved the stability and reproducibility of the ultraviolet continuum emitted by the plasma of the arc, which is used at the French National Institute of Metrology as a transfer standard of spectral radiance in the vacuum ultraviolet.

  9. Coordinate metrology accuracy of systems and measurements

    CERN Document Server

    Sładek, Jerzy A

    2016-01-01

    This book focuses on effective methods for assessing the accuracy of both coordinate measuring systems and coordinate measurements. It mainly reports on original research work conducted by Sladek’s team at Cracow University of Technology’s Laboratory of Coordinate Metrology. The book describes the implementation of different methods, including artificial neural networks, the Matrix Method, the Monte Carlo method and the virtual CMM (Coordinate Measuring Machine), and demonstrates how these methods can be effectively used in practice to gauge the accuracy of coordinate measurements. Moreover, the book includes an introduction to the theory of measurement uncertainty and to key techniques for assessing measurement accuracy. All methods and tools are presented in detail, using suitable mathematical formulations and illustrated with numerous examples. The book fills an important gap in the literature, providing readers with an advanced text on a topic that has been rapidly developing in recent years. The book...

  10. Hyperfine phononic frequency comb

    CERN Document Server

    Ganesan, Adarsh; Seshia, Ashwin A

    2016-01-01

    Optical frequency combs [1-8] have resulted in significant advances in optical frequency metrology and found wide application to precise physical measurements [1-4, 9] and molecular fingerprinting [8]. A direct analogue of frequency combs in the phononic or acoustic domain has not been reported to date. In this letter, we report the first clear experimental evidence for a phononic frequency comb. In contrast to the Kerr nonlinearity [10] in optical frequency comb formation, the phononic frequency comb is generated through the intrinsic coupling of a driven phonon mode with an auto-parametrically excited sub-harmonic mode [16]. Through systematic experiments at different drive frequencies and amplitudes, we portray the well-connected process of phononic frequency comb formation and define attributes to control the features [17-18] associated with comb formation in such a system. Further, the interplay between these nonlinear resonances and the well-known Duffing phenomenon [12-14] is also observed. The present...

  11. Cylindrical PVF2 film based fiber optic phase modulator - Phase shift nonlinearity and frequency response

    Science.gov (United States)

    Sudarshanam, V. S.; Claus, Richard O.

    1993-03-01

    A new cylindrical coil configuration for polyvinylidene flouride (PVF2) film based fiber optic phase modulator is studied for the frequency response and nonlinearity of phase shift at the resonance frequency. This configuration, hitherto unapproached for PVF2 film modulators, offers resonance at well defined, controllable and higher frequencies than possible for the flat-strip configuration. Two versions of this configuration are presented that differ strongly in both the resonance frequency and the phase shift nonlinearity coefficient.

  12. Performance of a novel carrier frequency offset estimation algorithm for OFDM-based WLANs

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This paper presents a novel carrier frequency offset estimation (CFO) algorithm for orthogonal frequency division multiplexing (OFDM)-based Wireless Local Area Networks (WLANs). Compared with previous approaches, this paper extends the whole frequency offset acquisition range by embedding a synthetic algorithm according to the preamble structure of WLANs symbols. The numerical results presented support the effectiveness of this algorithm by which the estimation error of the whole carrier frequency offset in the WLANs is effectively decreased.

  13. Calibration of Galileo signals for time metrology.

    Science.gov (United States)

    Defraigne, Pascale; Aerts, Wim; Cerretto, Giancarlo; Cantoni, Elena; Sleewaegen, Jean-Marie

    2014-12-01

    Using global navigation satellite system (GNSS) signals for accurate timing and time transfer requires the knowledge of all electric delays of the signals inside the receiving system. GNSS stations dedicated to timing or time transfer are classically calibrated only for Global Positioning System (GPS) signals. This paper proposes a procedure to determine the hardware delays of a GNSS receiving station for Galileo signals, once the delays of the GPS signals are known. This approach makes use of the broadcast satellite inter-signal biases, and is based on the ionospheric delay measured from dual-frequency combinations of GPS and Galileo signals. The uncertainty on the so-determined hardware delays is estimated to 3.7 ns for each isolated code in the L5 frequency band, and 4.2 ns for the ionosphere-free combination of E1 with a code of the L5 frequency band. For the calibration of a time transfer link between two stations, another approach can be used, based on the difference between the common-view time transfer results obtained with calibrated GPS data and with uncalibrated Galileo data. It is shown that the results obtained with this approach or with the ionospheric method are equivalent.

  14. Dependence of microwave-excitation signal parameters on frequency stability of caesium atomic clock

    Science.gov (United States)

    Petrov, A. A.; Davydov, V. V.; Vologdin, V. A.; Zalyotov, D. V.

    2015-11-01

    New scheme of the microwave - excitation signal for the caesium atomic clock is based on method of direct digital synthesis. The theoretical calculations and experimental research showed decrease step frequency tuning by several orders and improvement the spectral characteristics of the output signal of frequency synthesizer. A range of generated output frequencies is expanded, and the possibility of detuning the frequency of the neighboring resonance of spectral line that makes it possible to adjust the C-field in quantum frequency standard is implemented. Experimental research of the metrological characteristics of the quantum frequency standard on the atoms of caesium - 133 with new design scheme of the microwave - excitation signal showed improvement in daily frequency stability on 1.2*10-14.

  15. Inspection and calibration of theodolites by Metrological laboratory of the Military Geographical Institute of the Serbian Armed Forces

    Directory of Open Access Journals (Sweden)

    Radojčić Stevan M.

    2014-01-01

    Full Text Available This paper describes procedures for inspection and calibration of theodolites, the surveying instruments designed for angle measurements in horizontal as well as in vertical plains, which is in use by the Military Geographical Institute (as a matter of fact, its Metrological laboratory ML 06. The paper has an example of the records of the measurements. Those procedures are based on the German standard DIN 18723-3 published in 1990, as well as on ISO 17123-3:2001, and elaborated in details by metrological instruction MUP 143500V-01.

  16. Exoskeleton control for lower-extremity assistance based on adaptive frequency oscillators: adaptation of muscle activation and movement frequency.

    Science.gov (United States)

    Aguirre-Ollinger, Gabriel

    2015-01-01

    In this article, we analyze a novel strategy for assisting the lower extremities based on adaptive frequency oscillators. Our aim is to use the control algorithm presented here as a building block for the control of powered lower-limb exoskeletons. The algorithm assists cyclic movements of the human extremities by synchronizing actuator torques with the estimated net torque exerted by the muscles. Synchronization is produced by a nonlinear dynamical system combining an adaptive frequency oscillator with a form of adaptive Fourier analysis. The system extracts, in real time, the fundamental frequency component of the net muscle torque acting on a specific joint. Said component, nearly sinusoidal in shape, is the basis for the assistive torque waveform delivered by the exoskeleton. The action of the exoskeleton can be interpreted as a virtual reduction in the mechanical impedance of the leg. We studied the ability of human subjects to adapt their muscle activation to the assistive torque. Ten subjects swung their extended leg while coupled to a stationary hip joint exoskeleton. The experiment yielded a significant decrease, with respect to unassisted movement, of the activation levels of an agonist/antagonist pair of muscles controlling the hip joint's motion, which suggests the exoskeleton control has potential for assisting human gait. A moderate increase in swing frequency was observed as well. We theorize that the increase in frequency can be explained by the impedance model of the assisted leg. Per this model, subjects adjust their swing frequency in order to control the amount of reduction in net muscle torque.

  17. Base Level Management of Radio Frequency Radiation Protection Program

    Science.gov (United States)

    1989-04-01

    with a healti h....:d. V. STANDARDS A. The Basis of Our Permissible Exposure Limits (PELs). 1. What level of RFR is safe? It’s a big question, and a lot...mobile lifting equipment, hand-held radios, climbing gear, etc. b. Check out your equipment. Is the calibration current? Does the probe frequency range...CH--Hazardous levels possible, but only in areas that require climbing . GH--Ground-level hazardous exposures possible. DL--Transmitter dummy loaded. SH

  18. Mid-IR Microresonator-Based Optical Frequency Combs

    Science.gov (United States)

    2015-09-01

    the atmosphere and overlaps with strong absorption bands of important greenhouse gases such as carbon dioxide (~4.2m) and nitrous oxide (~4.4m...frequency combs (Kerr combs) generated by cascading parametric nonlinear effects in whispering gallery mode (WGM) crystalline microresonators. The...quantitatively study the effect of the resonator morphology and mode characteristics on its GVD, with the goal of creating ideal conditions for mid-IR

  19. Analytical Dielectric Spectrum Formula Based on Representative Frequencies

    Institute of Scientific and Technical Information of China (English)

    Bo Kong; Ke-xiang Fu; Min-hua Shan; Xiang-yuan Li

    2009-01-01

    According to experimental data available for the complex refractive index of particular di-electrics, a dielectric spectrum formula is proposed by the least square fitting technique combined with selected natural frequencies. From the dielectric spectrum formula, the spec-tra of optical and dielectric constants can be obtained in the whole frequency region. Three dielectrics, water, ethanol, and toluene, are taken as examples. In the region where the ex-perimental data are available, the spectra of the optical constants calculated by the formula are in good agreement with the real refractive spectrum obtained by Kramers-Kronig (K-K) transform and the experimental imaginary refractive spectrum. In the region where no ex-perimental data are available, the extrapolation of our formula can make predictions. The merits of the present treatment are that we are able to get the uniform spectrum formula, without splitting into different frequency sections, and the analytical form of the dielectric spectra will be useful in the theoretical description of solvation dynamics.

  20. Sparse time-frequency decomposition based on dictionary adaptation.

    Science.gov (United States)

    Hou, Thomas Y; Shi, Zuoqiang

    2016-04-13

    In this paper, we propose a time-frequency analysis method to obtain instantaneous frequencies and the corresponding decomposition by solving an optimization problem. In this optimization problem, the basis that is used to decompose the signal is not known a priori. Instead, it is adapted to the signal and is determined as part of the optimization problem. In this sense, this optimization problem can be seen as a dictionary adaptation problem, in which the dictionary is adaptive to one signal rather than a training set in dictionary learning. This dictionary adaptation problem is solved by using the augmented Lagrangian multiplier (ALM) method iteratively. We further accelerate the ALM method in each iteration by using the fast wavelet transform. We apply our method to decompose several signals, including signals with poor scale separation, signals with outliers and polluted by noise and a real signal. The results show that this method can give accurate recovery of both the instantaneous frequencies and the intrinsic mode functions.

  1. Mechanical control of a microrod-resonator optical frequency comb

    CERN Document Server

    Papp, Scott B; Diddams, Scott A

    2012-01-01

    Robust control and stabilization of optical frequency combs enables an extraordinary range of scientific and technological applications, including frequency metrology at extreme levels of precision, novel spectroscopy of quantum gases and of molecules from visible wavelengths to the far infrared, searches for exoplanets, and photonic waveform synthesis. Here we report on the stabilization of a microresonator-based optical comb (microcomb) by way of mechanical actuation. This represents an important step in the development of microcomb technology, which offers a pathway toward fully-integrated comb systems. Residual fluctuations of our 32.6 GHz microcomb line spacing reach a record stability level of $5\\times10^{-15}$ for 1 s averaging, thereby highlighting the potential of microcombs to support modern optical frequency standards. Furthermore, measurements of the line spacing with respect to an independent frequency reference reveal the effective stabilization of different spectral slices of the comb with a $&...

  2. Preparation and Characterisation of Exfoliated Graphene for Quantum Resistance Metrology

    NARCIS (Netherlands)

    Rietveld, G.; Elferen, H.J. van; Giesbers, A.J.M.; Veligura, A.; Zeitler, U.; Novoselov, K.S.; Wees, B.J. van; Geim, A.K.; Maan, J.C.

    2010-01-01

    Exfoliated graphene samples have been prepared for use in quantum resistance metrology. Good progress is recently made in achieving contact resistances to graphene of less than 50 Ω. Details are presented on the handling and measurement of graphene samples.

  3. Optical Fabrication and Metrology of Aspheric and Freeform Mirrors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The requirement for cost effective manufacturing and metrology of large optical surfaces is instrumental for the success of future NASA programs such as LISA, WFIRST...

  4. Towards Photonics Enabled Quantum Metrology of Temperature, Pressure and Vacuum

    CERN Document Server

    Ahmed, Zeeshan; Douglass, Kevin; Fedchak, Jim; Scherschligt, Julia; Hendricks, Jay; Ricker, Jacob; Strouse, Gregory

    2016-01-01

    This chapter presents a brief overview of photonic sensor and standards development that is currently undergoing in the thermodynamic metrology group at NIST in the areas of temperature, pressure, vacuum and time-resolved pressure measurements.

  5. Consultative committee on ionizing radiation: Impact on radionuclide metrology.

    Science.gov (United States)

    Karam, L R; Ratel, G

    2016-03-01

    In response to the CIPM MRA, and to improve radioactivity measurements in the face of advancing technologies, the CIPM's consultative committee on ionizing radiation developed a strategic approach to the realization and validation of measurement traceability for radionuclide metrology. As a consequence, measurement institutions throughout the world have devoted no small effort to establish radionuclide metrology capabilities, supported by active quality management systems and validated through prioritized participation in international comparisons, providing a varied stakeholder community with measurement confidence.

  6. Strain Sensor of Carbon Nanotubes in Microscale: From Model to Metrology

    Directory of Open Access Journals (Sweden)

    Wei Qiu

    2014-01-01

    Full Text Available A strain sensor composed of carbon nanotubes with Raman spectroscopy can achieve measurement of the three in-plane strain components in microscale. Based on previous work on the mathematic model of carbon nanotube strain sensors, this paper presents a detailed study on the optimization, diversification, and standardization of a CNT strain sensor from the viewpoint of metrology. A new miniaccessory for polarization control is designed, and two different preparing methods for CNT films as sensing media are introduced to provide diversified choices for applications. Then, the standard procedure of creating CNT strain sensors is proposed. Application experiments confirmed the effectiveness of the above improvement, which is helpful in developing this method for convenient metrology.

  7. In-plane displacement measurement in vortex metrology by synthetic network correlation fringes.

    Science.gov (United States)

    Angel-Toro, Luciano; Sierra-Sosa, Daniel; Tebaldi, Myrian; Bolognini, Néstor

    2013-03-01

    Recently we proposed an alternative method of displacement analysis in vortex metrology, based on the application of the Fourier optics techniques, that is suitable for an intermediate range of displacement measurements ranging below the resolution of speckle photography and above that of the conventional vortex metrology. However, for smaller displacements, we introduce an approach to perform the Fourier analysis from vortex networks. In this work, we present an enhanced method for measuring uniform in-plane displacements, taking advantage of the capability of determining the subpixel locations of vortices and having the ability to track the homologous vortices onto a plane. It is shown that high-quality fringe systems can be synthesized and analyzed to accurately measure in an extended range of displacements and for highly decorrelated speckle patterns. Experimental results supporting the validity of the method are presented and discussed.

  8. Strain sensor of carbon nanotubes in microscale: from model to metrology.

    Science.gov (United States)

    Qiu, Wei; Li, Shi-Lei; Deng, Wei-Lin; Gao, Di; Kang, Yi-Lan

    2014-01-01

    A strain sensor composed of carbon nanotubes with Raman spectroscopy can achieve measurement of the three in-plane strain components in microscale. Based on previous work on the mathematic model of carbon nanotube strain sensors, this paper presents a detailed study on the optimization, diversification, and standardization of a CNT strain sensor from the viewpoint of metrology. A new miniaccessory for polarization control is designed, and two different preparing methods for CNT films as sensing media are introduced to provide diversified choices for applications. Then, the standard procedure of creating CNT strain sensors is proposed. Application experiments confirmed the effectiveness of the above improvement, which is helpful in developing this method for convenient metrology.

  9. Advanced hardware and software methods for thread and gear dimensional metrology. CRADA final report

    Energy Technology Data Exchange (ETDEWEB)

    Miller, A.C. Jr.; Grann, E.B.

    1997-03-05

    The Oak Ridge Centers for Manufacturing Technology (ORCMT) and Apeiron Incorporated have collaborated on an effort to develop a frequency modulated continuous wave (FMCW) fiber lidar system for dimensional metrology of internal threads, gears, and splines. The purpose of this effort was to assist a small company in developing an instrument that would exceed the performance of competing foreign instruments and provide measurement capabilities necessary to assure compliance for NASA facilities and other industrial facilities. The two parties collaborated on design, assembly, and bench testing of the prototype instrument. The prototype system was targeted to have the capability of profiling internally machined gears and threads to an accuracy of less than a micron.

  10. Wireless Chalcogenide Nanoionic-Based Radio-Frequency Switch

    Science.gov (United States)

    Nessel, James; Miranda, Felix

    2013-01-01

    A new nonvolatile nanoionic switch is powered and controlled through wireless radio-frequency (RF) transmission. A thin layer of chalcogenide glass doped with a metal ion, such as silver, comprises the operational portion of the switch. For the switch to function, an oxidizable electrode is made positive (anode) with respect to an opposing electrode (cathode) when sufficient bias, typically on the order of a few tenths of a volt or more, is applied. This action causes the metal ions to flow toward the cathode through a coordinated hopping mechanism. At the cathode, a reduction reaction occurs to form a metal deposit. This metal deposit creates a conductive path that bridges the gap between electrodes to turn the switch on. Once this conductive path is formed, no further power is required to maintain it. To reverse this process, the metal deposit is made positive with respect to the original oxidizable electrode, causing the dissolution of the metal bridge thereby turning the switch off. Once the metal deposit has been completely dissolved, the process self-terminates. This switching process features the following attributes. It requires very little to change states (i.e., on and off). Furthermore, no power is required to maintain the states; hence, the state of the switch is nonvolatile. Because of these attributes the integration of a rectenna to provide the necessary power and control is unique to this embodiment. A rectenna, or rectifying antenna, generates DC power from an incident RF signal. The low voltages and power required for the nanoionic switch control are easily generated from this system and provide the switch with a novel capability to be operated and powered from an external wireless device. In one realization, an RF signal of a specific frequency can be used to set the switch into an off state, while another frequency can be used to set the switch to an on state. The wireless, miniaturized, and nomoving- part features of this switch make it

  11. Metrology in electricity and magnetism: EURAMET activities today and tomorrow

    Science.gov (United States)

    Piquemal, F.; Jeckelmann, B.; Callegaro, L.; Hällström, J.; Janssen, T. J. B. M.; Melcher, J.; Rietveld, G.; Siegner, U.; Wright, P.; Zeier, M.

    2017-10-01

    Metrology dedicated to electricity and magnetism has changed considerably in recent years. It encompasses almost all modern scientific, industrial, and societal challenges, e.g. the revision of the International System of Units, the profound transformation of industry, changes in energy use and generation, health, and environment, as well as nanotechnologies (including graphene and 2D materials) and quantum engineering. Over the same period, driven by the globalization of worldwide trade, the Mutual Recognition Arrangement (referred to as the CIPM MRA) was set up. As a result, the regional metrology organizations (RMOs) of national metrology institutes have grown in significance. EURAMET is the European RMO and has been very prominent in developing a strategic research agenda (SRA) and has established a comprehensive research programme. This paper reviews the highlights of EURAMET in electrical metrology within the European Metrology Research Programme and its main contributions to the CIPM MRA. In 2012 EURAMET undertook an extensive roadmapping exercise for proposed activities for the next decade which will also be discussed in this paper. This work has resulted in a new SRA of the second largest European funding programme: European Metrology Programme for Innovation and Research.

  12. Frequency-domain equalization for OFDMA-based multiuser MIMO systems with improper modulation schemes

    Science.gov (United States)

    Xiao, Pei; Lin, Zihuai; Fagan, Anthony; Cowan, Colin; Vucetic, Branka; Wu, Yi

    2011-12-01

    In this paper, we propose a novel transceiver structure for orthogonal frequency division multiple access-based uplink multiuser multiple-input multiple-output systems. The numerical results show that the proposed frequency-domain equalization schemes significantly outperform conventional linear minimum mean square error-based equalizers in terms of bit error rate performance with moderate increase in computational complexity.

  13. Memory-based mismatch response to frequency changes in rats.

    Directory of Open Access Journals (Sweden)

    Piia Astikainen

    Full Text Available Any occasional changes in the acoustic environment are of potential importance for survival. In humans, the preattentive detection of such changes generates the mismatch negativity (MMN component of event-related brain potentials. MMN is elicited to rare changes ('deviants' in a series of otherwise regularly repeating stimuli ('standards'. Deviant stimuli are detected on the basis of a neural comparison process between the input from the current stimulus and the sensory memory trace of the standard stimuli. It is, however, unclear to what extent animals show a similar comparison process in response to auditory changes. To resolve this issue, epidural potentials were recorded above the primary auditory cortex of urethane-anesthetized rats. In an oddball condition, tone frequency was used to differentiate deviants interspersed randomly among a standard tone. Mismatch responses were observed at 60-100 ms after stimulus onset for frequency increases of 5% and 12.5% but not for similarly descending deviants. The response diminished when the silent inter-stimulus interval was increased from 375 ms to 600 ms for +5% deviants and from 600 ms to 1000 ms for +12.5% deviants. In comparison to the oddball condition the response also diminished in a control condition in which no repetitive standards were presented (equiprobable condition. These findings suggest that the rat mismatch response is similar to the human MMN and indicate that anesthetized rats provide a valuable model for studies of central auditory processing.

  14. An Investigation into Error Source Identification of Machine Tools Based on Time-Frequency Feature Extraction

    Directory of Open Access Journals (Sweden)

    Dongju Chen

    2016-01-01

    Full Text Available This paper presents a new identification method to identify the main errors of the machine tool in time-frequency domain. The low- and high-frequency signals of the workpiece surface are decomposed based on the Daubechies wavelet transform. With power spectral density analysis, the main features of the high-frequency signal corresponding to the imbalance of the spindle system are extracted from the surface topography of the workpiece in the frequency domain. With the cross-correlation analysis method, the relationship between the guideway error of the machine tool and the low-frequency signal of the surface topography is calculated in the time domain.

  15. Islanding Detection for Microgrid Based on Frequency Tracking Using Extended Kalman Filter Algorithm

    Directory of Open Access Journals (Sweden)

    Bin Li

    2014-01-01

    Full Text Available Islanding detection is essential for secure and reliable operation of microgrids. Considering the relationship between the power generation and the load in microgrids, frequency may vary with time when islanding occurs. As a common approach, frequency measurement is widely used to detect islanding condition. In this paper, a novel frequency calculation algorithm based on extended Kalman filter was proposed to track dynamic frequency of the microgrid. Taylor series expansion was introduced to solve nonlinear state equations. In addition, a typical microgrid model was built using MATLAB/SIMULINK. Simulation results demonstrated that the proposed algorithm achieved great stability and strong robustness in of tracking dynamic frequency.

  16. History of reference materials for food and nutrition metrology: As represented in the series of BERM Symposia

    Science.gov (United States)

    Establishment of a metrology-based measurement system requires the solid foundation of traceability of measurements to available, appropriate certified reference materials (CRM). In the early 1970s the first “biological” Reference Material (RM) of Bowens Kale, Orchard Leaves, and Bovine Liver from ...

  17. Metrology of Large Parts. Chapter 5

    Science.gov (United States)

    Stahl, H. Philip

    2012-01-01

    As discussed in the first chapter of this book, there are many different methods to measure a part using optical technology. Chapter 2 discussed the use of machine vision to measure macroscopic features such as length and position, which was extended to the use of interferometry as a linear measurement tool in chapter 3, and laser or other trackers to find the relation of key points on large parts in chapter 4. This chapter looks at measuring large parts to optical tolerances in the sub-micron range using interferometry, ranging, and optical tools discussed in the previous chapters. The purpose of this chapter is not to discuss specific metrology tools (such as interferometers or gauges), but to describe a systems engineering approach to testing large parts. Issues such as material warpage and temperature drifts that may be insignificant when measuring a part to micron levels under a microscope, as will be discussed in later chapters, can prove to be very important when making the same measurement over a larger part. In this chapter, we will define a set of guiding principles for successfully overcoming these challenges and illustrate the application of these principles with real world examples. While these examples are drawn from specific large optical testing applications, they inform the problems associated with testing any large part to optical tolerances. Manufacturing today relies on micrometer level part performance. Fields such as energy and transportation are demanding higher tolerances to provide increased efficiencies and fuel savings. By looking at how the optics industry approaches sub-micrometer metrology, one can gain a better understanding of the metrology challenges for any larger part specified to micrometer tolerances. Testing large parts, whether optical components or precision structures, to optical tolerances is just like testing small parts, only harder. Identical with what one does for small parts, a metrologist tests large parts and optics

  18. CONFERENCE NOTE: International Workshop on Advanced Mathematical Tools in Metrology, Villa Gualino, Torino, Italy, 20 22 October 1993

    Science.gov (United States)

    1993-01-01

    Preliminary Programme The three-day programme features approximately twenty-five invited contributions. Participants may present a poster on the topic "Applications for Industrial Measurements", concerning applied mathematics, software development and computer-based measurements. 20 October Two plenary talks on mathematical methods and metrological applications "Numerical Methods and Modelling" Partial differential equations and integral equations Methods of identification and validation Algorithms for approximation Geometrical shape determination of industrial solids Round Table 21 October "Data Analysis" Spectral analysis and wavelets Calibration of precision instrumentation Comparison measurement of standards Statistical methods in metrology Robust estimation and outliers Applications of the bootstrap method Round Table 22 October (in cooperation with SIMAI and ASP) "Applications for Industrial Measurements" Data acquisition Measurement software, standard computational modules and their validation Round Table Industrial presentations Discussion of poster presentations Conclusions Lecturers Mathematicians from the international metrological community; mathematicians from Italian universities (Politecnico of Torino, Milano, Università di Genova, Milano, Padova, Roma, Trento); scientists and mathematicians from national standards institutes and the Italian National Research Council. The workshop will be of interest to people in universities, research centres and industry who are involved in measurement and need advanced mathematical tools to solve their problems, and to those who work in the development of these mathematical tools. Metrology is concerned with measurement at the highest level of precision. Advances in metrology depend on many factors: improvements in scientific and technical knowledge, instrumentation quality, better use of advanced mathematical tools and the development of new tools. In some countries, metrological institutions have a tradition of

  19. Mercury Atomic Frequency Standards for Space Based Navigation and Timekeeping

    Science.gov (United States)

    Tjoelker, R. L.; Burt, E. A.; Chung, S.; Hamell, R. L.; Prestage, J. D.; Tucker, B.; Cash, P.; Lutwak, R.

    2012-01-01

    A low power Mercury Atomic Frequency Standard (MAFS) has been developed and demonstrated on the path towards future space clock applications. A self contained mercury ion breadboard clock: emulating flight clock interfaces, steering a USO local oscillator, and consuming approx 40 Watts has been operating at JPL for more than a year. This complete, modular ion clock instrument demonstrates that key GNSS size, weight, and power (SWaP) requirements can be achieved while still maintaining short and long term performance demonstrated in previous ground ion clocks. The MAFS breadboard serves as a flexible platform for optimizing further space clock development and guides engineering model design trades towards fabrication of an ion clock for space flight.

  20. Fast LCMV-based Methods for Fundamental Frequency Estimation

    DEFF Research Database (Denmark)

    Jensen, Jesper Rindom; Glentis, George-Othon; Christensen, Mads Græsbøll

    2013-01-01

    Recently, optimal linearly constrained minimum variance (LCMV) filtering methods have been applied to fundamental frequency estimation. Such estimators often yield preferable performance but suffer from being computationally cumbersome as the resulting cost functions are multimodal with narrow...... as such either the classic time domain averaging covariance matrix estimator, or, if aiming for an increased spectral resolution, the covariance matrix resulting from the application of the recent iterative adaptive approach (IAA). The proposed exact implementations reduce the required computational complexity...... be efficiently updated when new observations become available. The resulting time-recursive updating can reduce the computational complexity even further. The experimental results show that the performances of the proposed methods are comparable or better than that of other competing methods in terms of spectral...

  1. Mercury Atomic Frequency Standards for Space Based Navigation and Timekeeping

    Science.gov (United States)

    Tjoelker, R. L.; Burt, E. A.; Chung, S.; Hamell, R. L.; Prestage, J. D.; Tucker, B.; Cash, P.; Lutwak, R.

    2012-01-01

    A low power Mercury Atomic Frequency Standard (MAFS) has been developed and demonstrated on the path towards future space clock applications. A self contained mercury ion breadboard clock: emulating flight clock interfaces, steering a USO local oscillator, and consuming approx 40 Watts has been operating at JPL for more than a year. This complete, modular ion clock instrument demonstrates that key GNSS size, weight, and power (SWaP) requirements can be achieved while still maintaining short and long term performance demonstrated in previous ground ion clocks. The MAFS breadboard serves as a flexible platform for optimizing further space clock development and guides engineering model design trades towards fabrication of an ion clock for space flight.

  2. Welcome to Surface Topography: Metrology and Properties

    Science.gov (United States)

    Leach, Richard

    2013-11-01

    I am delighted to welcome readers to this inaugural issue of Surface Topography: Metrology and Properties (STMP). In these days of citation indexes and academic reviews, it is a tough, and maybe a brave, job to start a new journal. But the subject area has never been more active and we are seeing genuine breakthroughs in the use of surfaces to control functional performance. Most manufactured parts rely on some form of control of their surface characteristics. The surface is usually defined as that feature on a component or device, which interacts with either the environment in which it is housed (or in which the device operates), or with another surface. The surface topography and material characteristics of a part can affect how fluids interact with it, how the part looks and feels and how two bearing parts will slide together. The need to control, and hence measure, surface features is becoming increasingly important as we move into a miniaturized world. Surface features can become the dominant functional features of a part and may become large in comparison to the overall size of an object. Research into surface texture measurement and characterization has been carried out for over a century and is now more active than ever, especially as new areal surface texture specification standards begin to be introduced. The range of disciplines for which the function of a surface relates to its topography is very diverse; from metal sheet manufacturing to art restoration, from plastic electronics to forensics. Until now, there has been no obvious publishing venue to bring together all these applications with the underlying research and theory, or to unite those working in academia with engineering and industry. Hence the creation of Surface Topography: Metrology and Properties . STMP will publish the best work being done across this broad discipline in one journal, helping researchers to share common themes and highlighting and promoting the extraordinary benefits this

  3. Measurement of a discontinuous object based on a dual-frequency grating

    Institute of Scientific and Technical Information of China (English)

    Qiao Nao-Sheng; Cai Xin-Hua; Yao Chun-Mei

    2009-01-01

    The dual-frequency grating measurement theory is proposed in order to carry out the measurement of a discontinuous object. Firstly, the reason why frequency spectra are produced by low frequency gratings and high frequency gratings in the field of frequency is analysed, and the relationship between the wrapped-phase and the unwrappingphase is discussed. Secondly, a method to combine the advantages of the two kinds of gratings is proposed: one stripe is produced in the mutation part of the object measured by a suitable low frequency grating designed by MATLAB, then the phase produced by the low frequency grating need not be unfolded. The integer series of stripes is produced by a high frequency grating designed by MATLAB based on the frequency ratio of the two kinds of gratings and the high frequency wrapped-phase, and the high frequency unwrapping-phase is then obtained. In order to verify the correctness of the theoretical analysis, a steep discontinuous object of 600×600 pixels and 10.00 mm in height is simulated and a discontinuous object of ladder shape which is 32.00 mm in height is used in experiment. Both the simulation and the experiment can restore the discontinuous object height accurately by using the dual-frequency grating measurement theory.

  4. Joint Estimation of Time-Frequency Signature and DOA Based on STFD for Multicomponent Chirp Signals.

    Science.gov (United States)

    Zhao, Ziyue; Liu, Congfeng

    2014-01-01

    In the study of the joint estimation of time-frequency signature and direction of arrival (DOA) for multicomponent chirp signals, an estimation method based on spatial time-frequency distributions (STFDs) is proposed in this paper. Firstly, array signal model for multicomponent chirp signals is presented and then array processing is applied in time-frequency analysis to mitigate cross-terms. According to the results of the array processing, Hough transform is performed and the estimation of time-frequency signature is obtained. Subsequently, subspace method for DOA estimation based on STFD matrix is achieved. Simulation results demonstrate the validity of the proposed method.

  5. Design of High Frequency Power Oscillator Board Based on Rotary Encoder Control

    Directory of Open Access Journals (Sweden)

    Jiang Shifen

    2013-06-01

    Full Text Available Accurate and stable high frequency pulse power supply is studied to improve high-speed wedm machine tool's efficiency. Regarding to the shortcomings of traditional digital circuit high frequency oscillator board, we design a high frequency power oscillator board based on rotary encoder control, control accuracy and high-frequency waveform by programming, adjusting the frequency and display. It has six brakes of processing function, it also includes feedback function of emulsification oil. The high frequency will be shutdown and the emulsification oil will be changed if there is too much metal dust in emulsification. It has been proved by practice that high-frequency circuit board is simple and reliable and can greatly increase efficiency of wire cutting.

  6. Sub-50 nm metrology on extreme ultra violet chemically amplified resist--A systematic assessment.

    Science.gov (United States)

    Maas, D J; Fliervoet, T; Herfst, R; van Veldhoven, E; Meessen, J; Vaenkatesan, V; Sadeghian, H

    2015-10-01

    With lithographic patterning dimensions decreasing well below 50 nm, it is of high importance to understand metrology at such small scales. This paper presents results obtained from dense arrays of contact holes (CHs) with various Critical Dimension (CD) between 15 and 50 nm, as patterned in a chemically amplified resist using an ASML EUV scanner and measured at ASML and TNO. To determine the differences between various (local) CD metrology techniques, we conducted an experiment using optical scatterometry, CD-Scanning Electron Microscopy (CD-SEM), Helium ion Microscopy (HIM), and Atomic Force Microscopy (AFM). CD-SEM requires advanced beam scan strategies to mitigate sample charging; the other tools did not need that. We discuss the observed main similarities and differences between the various techniques. To this end, we assessed the spatial frequency content in the raw images for SEM, HIM, and AFM. HIM and AFM resolve the highest spatial frequencies, which are attributed to the more localized probe-sample interaction for these techniques. Furthermore, the SEM, HIM, and AFM waveforms are analyzed in detail. All techniques show good mutual correlation, albeit the reported CD values systematically differ significantly. HIM systematically reports a 25% higher CD uniformity number than CD-SEM for the same arrays of CHs, probably because HIM has a higher resolution than the CD-SEM used in this assessment. A significant speed boost for HIM and AFM is required before these techniques are to serve the demanding industrial metrology applications like optical critical dimension and CD-SEM do nowadays.

  7. Soil Moisture Sensing via Swept Frequency Based Microwave Sensors

    Directory of Open Access Journals (Sweden)

    Greg A. Holt

    2012-01-01

    Full Text Available There is a need for low-cost, high-accuracy measurement of water content in various materials. This study assesses the performance of a new microwave swept frequency domain instrument (SFI that has promise to provide a low-cost, high-accuracy alternative to the traditional and more expensive time domain reflectometry (TDR. The technique obtains permittivity measurements of soils in the frequency domain utilizing a through transmission configuration, transmissometry, which provides a frequency domain transmissometry measurement (FDT. The measurement is comparable to time domain transmissometry (TDT with the added advantage of also being able to separately quantify the real and imaginary portions of the complex permittivity so that the measured bulk permittivity is more accurate that the measurement TDR provides where the apparent permittivity is impacted by the signal loss, which can be significant in heavier soils. The experimental SFI was compared with a high-end 12 GHz TDR/TDT system across a range of soils at varying soil water contents and densities. As propagation delay is the fundamental measurement of interest to the well-established TDR or TDT technique; the first set of tests utilized precision propagation delay lines to test the accuracy of the SFI instrument’s ability to resolve propagation delays across the expected range of delays that a soil probe would present when subjected to the expected range of soil types and soil moisture typical to an agronomic cropping system. The results of the precision-delay line testing suggests the instrument is capable of predicting propagation delays with a RMSE of +/−105 ps across the range of delays ranging from 0 to 12,000 ps with a coefficient of determination of r2 = 0.998. The second phase of tests noted the rich history of TDR for prediction of soil moisture and leveraged this history by utilizing TDT measured with a high-end Hewlett Packard TDR/TDT instrument to directly benchmark the

  8. Patient Preference for Dosing Frequency Based on Prior Biologic Experience.

    Science.gov (United States)

    Zhang, Mingliang; Carter, Chureen; Olson, William H; Johnson, Michael P; Brennem, Susan K; Lee, Seina; Farahi, Kamyar

    2017-03-01

    There is limited research exploring patient preferences regarding dosing frequency of biologic treatment of psoriasis. Patients with moderate-to-severe plaque psoriasis identified in a healthcare claims database completed a survey regarding experience with psoriasis treatments and preferred dosing frequency. Survey questions regarding preferences were posed in two ways: (1) by likelihood of choosing once per week or 2 weeks, or 12 weeks; and (2) by choosing one option among once every 1-2 or 3-4 weeks or 1-2 or 2-3 months. Data were analyzed by prior biologic history (biologic-experienced vs biologic-naïve, and with one or two specific biologics). Overall, 426 patients completed the survey: 163 biologic-naïve patients and 263 biologic-experienced patients (159 had some experience with etanercept, 105 with adalimumab, and 49 with ustekinumab). Among patients who indicated experience with one or two biologics, data were available for 219 (30 with three biologics and 14 did not specify which biologic experience). The majority of biologic-naïve (68.8%) and overall biologic-experienced (69.4%) patients indicated that they were very likely to choose the least frequent dosing option of once every 12 weeks (Table 1). In contrast, fewer biologic-naïve (9.1% and 16.7%) and biologic-experienced (22.5% and 25.3%) patients indicated that they were very likely to choose the 1-week and 2-week dosing interval options, respectively. In each cohort grouped by experience with specific biologics, among those with no experience with ustekinumab, the most chosen option was 1-2 weeks. The most frequently chosen option was every 2-3 months, among patients with any experience with ustekinumab, regardless of their experience with other biologics. The least frequent dosing interval was preferred among biologic naïve patients and patients who had any experience with ustekinumab. Dosing interval may influence the shared decision-making process for psoriasis treatment with biologics. J

  9. Genetic Algorithm based PID controller for Frequency Regulation Ancillary services

    Directory of Open Access Journals (Sweden)

    Sandeep Bhongade

    2010-12-01

    Full Text Available In this paper, the parameters of Proportional, Integral and Derivative (PID controller for Automatic Generation Control (AGC suitable in restructured power system is tuned according to Generic Algorithms (GAs based performance indices. The key idea of the proposed method is to use the fitness function based on Area Control Error (ACE. The functioning of the proposed Genetic Algorithm based PID (GAPID controller has been demonstrated on a 75-bus Indian power system network and the results have been compared with those obtained by using Least Square Minimization method.

  10. At-wavelength metrology of x-ray optics at Diamond Light Source

    Science.gov (United States)

    Wang, Hongchang; Berujon, Sebastien; Sutter, John; Alcock, Simon G.; Sawhney, Kawal

    2014-09-01

    Modern, third-generation synchrotron radiation sources provide coherent and extremely bright beams of X-ray radiation. The successful exploitation of such beams depends to a significant extent on imperfections and misalignment of the optics employed on the beamlines. This issue becomes even more critical with the increasing use of active optics, and the desire to achieve diffraction-limited and coherence-preserving X-ray beams. In recent years, significant progress has been made to improve optic testing and optimization techniques, especially those using X-rays for so-called atwavelength metrology. These in-situ and at-wavelength metrology methods can be used not only to optimize the performance of X-ray optics, but also to correct and minimize the collective distortions of upstream beamline optics, including monochromators, and transmission windows. An overview of at-wavelength metrology techniques implemented at Diamond Light Source is presented, including grating interferometry and X-ray near-field speckle based techniques. Representative examples of the application of these techniques are also given, including in-situ and atwavelength calibration and optimization of: active, piezo bimorph mirrors; Kirkpatrick-Baez (KB) mirrors; and refractive optics such as compound refractive lenses.

  11. Multiple frequencies sequential coding for SSVEP-based brain-computer interface.

    Directory of Open Access Journals (Sweden)

    Yangsong Zhang

    Full Text Available BACKGROUND: Steady-state visual evoked potential (SSVEP-based brain-computer interface (BCI has become one of the most promising modalities for a practical noninvasive BCI system. Owing to both the limitation of refresh rate of liquid crystal display (LCD or cathode ray tube (CRT monitor, and the specific physiological response property that only a very small number of stimuli at certain frequencies could evoke strong SSVEPs, the available frequencies for SSVEP stimuli are limited. Therefore, it may not be enough to code multiple targets with the traditional frequencies coding protocols, which poses a big challenge for the design of a practical SSVEP-based BCI. This study aimed to provide an innovative coding method to tackle this problem. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we present a novel protocol termed multiple frequencies sequential coding (MFSC for SSVEP-based BCI. In MFSC, multiple frequencies are sequentially used in each cycle to code the targets. To fulfill the sequential coding, each cycle is divided into several coding epochs, and during each epoch, certain frequency is used. Obviously, different frequencies or the same frequency can be presented in the coding epochs, and the different epoch sequence corresponds to the different targets. To show the feasibility of MFSC, we used two frequencies to realize four targets and carried on an offline experiment. The current study shows that: 1 MFSC is feasible and efficient; 2 the performance of SSVEP-based BCI based on MFSC can be comparable to some existed systems. CONCLUSIONS/SIGNIFICANCE: The proposed protocol could potentially implement much more targets with the limited available frequencies compared with the traditional frequencies coding protocol. The efficiency of the new protocol was confirmed by real data experiment. We propose that the SSVEP-based BCI under MFSC might be a promising choice in the future.

  12. Metrology Of Silicide Contacts For Future CMOS

    Science.gov (United States)

    Zollner, Stefan; Gregory, Richard B.; Kottke, M. L.; Vartanian, Victor; Wang, Xiang-Dong; Theodore, David; Fejes, P. L.; Conner, J. R.; Raymond, Mark; Zhu, Xiaoyan; Denning, Dean; Bolton, Scott; Chang, Kyuhwan; Noble, Ross; Jahanbani, Mohamad; Rossow, Marc; Goedeke, Darren; Filipiak, Stan; Garcia, Ricardo; Jawarani, Dharmesh; Taylor, Bill; Nguyen, Bich-Yen; Crabtree, P. E.; Thean, Aaron

    2007-09-01

    Silicide materials (NiSi, CoSi2, TiSi2, etc) are used to form low-resistance contacts between the back-end (W plugs and Cu interconnects) and front-end portions (silicon source, drain, and gate regions) of integrated CMOS circuits. At the 65 nm node, a transition from CoSi2 to NiSi was necessary because of the unique capability of NiSi to form narrow silicide nanowires on active (monocrystalline) and gate (polycrystalline) lines. Like its predecessors TiSi2 and CoSi2, NiSi is a mid-gap silicide, i.e., the Fermi level of the NiSi metal is pinned half-way between the conduction and valence band edges in silicon. This leads to a Schottky barrier between the silicide and silicon source-drain regions, which creates undesirable parasitic resistances. For future CMOS generations, band-edge silicides, such as PtSi for contacts to p-type or rare earth silicides for contacts to n-type Si will be needed. This paper reviews metrology and characterization techniques for NiSi process control for development and manufacturing, with special emphasis on x-ray reflectance and x-ray fluorescence. We also report measurement methods useful for development of a PtSi PMOS module.

  13. Metrology on phase-shift masks

    Science.gov (United States)

    Roeth, Klaus-Dieter; Maurer, Wilhelm; Blaesing-Bangert, Carola

    1992-06-01

    In the evaluation of new manufacturing processes, metrology is a key function, beginning with the first step of process development through the final step of everyday mass production at the fabrication floor level. RIM-type phase shift masks are expected to be the first application of phase shift masks in high volume production, since they provide improved lithography process capability at the expense of only moderate complexity in their manufacturing. Measurements of critical dimension (CD) and pattern position (overlay) on experimental rim-type and chromeless phase shift masks are reported. Pattern placement (registration) was measured using the Leitz LMS 2000. The overall design and important components were already described. The pattern placement of the RIM type phase shift structures on the photomask described above was determined within a tolerance of 25 nm (3s); nominal accuracy was within 45 nm (3s). On the chromeless phase shift mask the measurement results were easily obtained using a wafer intensity algorithm available with the system. The measurement uncertainties were less than 25 nm and 50 nm for precision and nominal accuracy respectively. The measurement results from the Leitz CD 200 using transmitted light were: a CD- distribution of 135 nm (3s) on a typical 6 micrometers structure all over the mask; the 0.9 micrometers RIM structure had a distribution of 43 nm (3s). Typical long term precision performance values for the CD 200 on both chrome and phase shift structures have been less than 15 nm.

  14. Hierarchical characterization procedures for dimensional metrology

    Science.gov (United States)

    MacKinnon, David; Beraldin, Jean-Angelo; Cournoyer, Luc; Carrier, Benjamin

    2011-03-01

    We present a series of dimensional metrology procedures for evaluating the geometrical performance of a 3D imaging system that have either been designed or modified from existing procedures to ensure, where possible, statistical traceability of each characteristic value from the certified reference surface to the certifying laboratory. Because there are currently no internationally-accepted standards for characterizing 3D imaging systems, these procedures have been designed to avoid using characteristic values provided by the vendors of 3D imaging systems. For this paper, we focus only on characteristics related to geometric surface properties, dividing them into surface form precision and surface fit trueness. These characteristics have been selected to be familiar to operators of 3D imaging systems that use Geometrical Dimensioning and Tolerancing (GD&T). The procedures for generating characteristic values would form the basis of either a volumetric or application-specific analysis of the characteristic profile of a 3D imaging system. We use a hierarchical approach in which each procedure builds on either certified reference values or previously-generated characteristic values. Starting from one of three classes of surface forms, we demonstrate how procedures for quantifying for flatness, roundness, angularity, diameter error, angle error, sphere-spacing error, and unidirectional and bidirectional plane-spacing error are built upon each other. We demonstrate how these procedures can be used as part of a process for characterizing the geometrical performance of a 3D imaging system.

  15. Relativistic quantum metrology in open system dynamics.

    Science.gov (United States)

    Tian, Zehua; Wang, Jieci; Fan, Heng; Jing, Jiliang

    2015-01-22

    Quantum metrology studies the ultimate limit of precision in estimating a physical quantity if quantum strategies are exploited. Here we investigate the evolution of a two-level atom as a detector which interacts with a massless scalar field using the master equation approach for open quantum system. We employ local quantum estimation theory to estimate the Unruh temperature when probed by a uniformly accelerated detector in the Minkowski vacuum. In particular, we evaluate the Fisher information (FI) for population measurement, maximize its value over all possible detector preparations and evolution times, and compare its behavior with that of the quantum Fisher information (QFI). We find that the optimal precision of estimation is achieved when the detector evolves for a long enough time. Furthermore, we find that in this case the FI for population measurement is independent of initial preparations of the detector and is exactly equal to the QFI, which means that population measurement is optimal. This result demonstrates that the achievement of the ultimate bound of precision imposed by quantum mechanics is possible. Finally, we note that the same configuration is also available to the maximum of the QFI itself.

  16. State-of-the-art attosecond metrology

    Energy Technology Data Exchange (ETDEWEB)

    Schultze, M., E-mail: martin.schultze@mpq.mpg.de [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Str. 1, D-85748 Garching (Germany); Department fuer Physik, Ludwig-Maximilians-Universitaet, Am Coulombwall 1, D-85748 Garching (Germany); Wirth, A.; Grguras, I.; Uiberacker, M.; Uphues, T.; Verhoef, A.J.; Gagnon, J. [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Str. 1, D-85748 Garching (Germany); Hofstetter, M.; Kleineberg, U. [Department fuer Physik, Ludwig-Maximilians-Universitaet, Am Coulombwall 1, D-85748 Garching (Germany); Goulielmakis, E. [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Str. 1, D-85748 Garching (Germany); Krausz, F. [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Str. 1, D-85748 Garching (Germany); Department fuer Physik, Ludwig-Maximilians-Universitaet, Am Coulombwall 1, D-85748 Garching (Germany)

    2011-04-15

    Research highlights: {yields} We present a complete setup for investigations with attosecond temporal resoultion. {yields} Few-cycle visible laser pulses are used to generate xray pulses approaching the atomic unit of time. {yields} Attosecond XUV pulses explore ultrafast electronic dynamics in atoms. - Abstract: Tracking and controlling electron dynamics in the interior of atoms, molecules as well as in solids is at the forefront of modern ultrafast science . Time-resolved studies of these dynamics require attosecond temporal resolution that is provided by an ensemble of techniques consolidated under the term 'attosecond metrology'. This work reports the development and commissioning of what we refer to as next-generation attosecond beamline technology: the AS-1 attosecond beamline at the Max-Planck Institute of Quantum Optics. It consists of a phase-stabilized few-cycle laser system, for the generation of XUV radiation, and modules tailored for the spectral filtering and isolation of attosecond pulses as well as for their temporal characterization. The setup produces the shortest attosecond pulses demonstrated to date and combines them with advanced spectroscopic instrumentation (electron-, ion- and XUV-spectrometers). These pulses serve as temporally confined trigger events (attosecond streaking and tunneling spectroscopy) or probe pulses (attosecond absorption and photoelectron spectroscopy) enabling attosecond chronoscopy to be applied to a broad range of systems belonging to the microcosm.

  17. OPC aware mask and wafer metrology

    Science.gov (United States)

    Maurer, Wilhelm; Wiaux, Vincent; Jonckheere, Rik M.; Philipsen, Vicky; Hoffmann, Thomas; Verhaegen, Staf; Ronse, Kurt G.; England, Jonathan G.; Howard, William B.

    2002-08-01

    Lithography at its limit of resolution is a highly non- linear pattern transfer process. Typically the shapes of printed features deviate considerably from their corresponding features in the layout. This deviation is known as Optical Proximity Effect, and its correction Optical Proximity effect Correction or OPC. Although many other so-called optical enhancement technologies are applied to cope with the issues of lithography at its limit of resolution, almost none of these can re-store the linearity of the pattern transfer. Hence fully functional OPC has become a very basic requirement for current and future lithography processes. In general, proximity effects are two-dimensional (2d) effects. Thus any measurement of proximity effects or any characterization of the effectiveness of OPC has to be two- dimensional. As OPC modifies shapes in the data for mask writing in a way to compensate for the expected proximity effects of the following processing steps, parameters describing the particular OPC-mask quality is a major concern. One-dimensional mask specifications, such as linewidth mean-to-target and uniformity, pattern placement, and maximum size of a tolerable defect, are not sufficient anymore to completely describe the functionality of a given mask for OPC. Two-dimensional mask specifications need to be evaluated. We present in this paper a basic concept for 2d metrology. Examples for 2d measurements to assess the effectiveness of OPC are given by the application of an SEM Image Analysis tool to an advanced 130nm process.

  18. Radio Frequency Based Programmable Logic Controller Anomaly Detection

    Science.gov (United States)

    2013-09-01

    Air Force Institute of Technology, Sep 2009. 57. Klein, R., M. Temple, and M. Mendenhall . “Application of Wavelet-Based RF Fingerprinting to Enhance...Wireless Network Security,” Jour of Communica- tions and Networks , 11 (6):544; 12; 114–555 (Dec 2009). 58. Klein, R., M. Temple, M. Mendenhall , and D...Selected Areas in Communications, IEEE (2012, UNDER REVIEW). 79. Reising, D., M. Temple, and M. Mendenhall . “Improved Wireless Security for GMSK Based

  19. Phase stabilization of Kerr frequency comb internally without nonlinear optical interferometry

    CERN Document Server

    Huang, S -W; Yang, J; Yu, M; Kwong, D -L; Wong, C W

    2016-01-01

    Optical frequency comb (OFC) technology has been the cornerstone for scientific breakthroughs such as precision frequency metrology, redefinition of time, extreme light-matter interaction, and attosecond sciences. While the current mode-locked laser-based OFC has had great success in extending the scientific frontier, its use in real-world applications beyond the laboratory setting remains an unsolved challenge. Microresonator-based OFCs, or Kerr frequency comb, have recently emerged as a candidate solution to the challenge because of their preferable size, weight, and power consumption (SWaP). On the other hand, the current phase stabilization technology requires either external optical references or power-demanding nonlinear processes, overturning the SWaP benefit of Kerr frequency combs. Introducing a new concept in phase control, here we report an internally phase stabilized Kerr frequency comb without the need of any optical references or nonlinear processes. We describe the comb generation analytically ...

  20. A Group-Period Phase Comparison Method Based on Equivalent Phase Comparison Frequency

    Institute of Scientific and Technical Information of China (English)

    DU Bao-Qiang; ZHOU Wei; DONG Shao-Feng; ZHOU Hai-Niu

    2009-01-01

    Based on the principle of equivalent phase comparison frequency, we propose a group-period phase comparison method. This method can be used to reveal the inherent relations between periodic signals and the change laws of the phase difference. If these laws are applied in the processing of the mutual relations between frequency signals, phase comparison can be accomplished without frequency normalization. Experimental results show that the method can enhance the measurement resolution to 10-13/s in the time domain.