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Christopher T Gibson - One of the best experts on this subject based on the ideXlab platform.
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Spring constant calibration techniques for next generation fast scanning atomic force microscope Cantilevers
Nanotechnology, 2014Co-Authors: Ashley D Slattery, Adam J Blanch, Vladimir Ejov, Jamie S Quinton, Christopher T GibsonAbstract:As a recent technological development, high-speed atomic force microscopy (AFM) has provided unprecedented insights into dynamic processes on the nanoscale, and is capable of measuring material property variation over short timescales. Miniaturized Cantilevers developed specifically for high-speed AFM differ greatly from standard Cantilevers both in size and dynamic properties, and calibration of the Cantilever Spring constant is critical for accurate, quantitative measurement. This work investigates specifically, the calibration of these new-generation Cantilevers for the first time. Existing techniques are tested and the challenges encountered are reported and the most effective approaches for calibrating fast-scanning Cantilevers with high accuracy are identified, providing a resource for microscopists in this rapidly developing field. Not only do these Cantilevers offer faster acquisition of images and force data but due to their high resonant frequencies (up to 2 MHz) they are also excellent mass sensors. Accurate measurement of deposited mass requires accurate calibration of the Cantilever Spring constant, therefore the results of this work will also be useful for mass-sensing applications.
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Accurate measurement of Atomic Force Microscope Cantilever deflection excluding tip-surface contact with application to force calibration.
Ultramicroscopy, 2013Co-Authors: Ashley D Slattery, Adam J Blanch, Jamie S Quinton, Christopher T GibsonAbstract:Considerable attention has been given to the calibration of AFM Cantilever Spring constants in the last 20 years. Techniques that do not require tip-sample contact are considered advantageous since the imaging tip is not at risk of being damaged. Far less attention has been directed toward measuring the Cantilever deflection or sensitivity, despite the fact that the primary means of determining this factor relies on the AFM tip being pressed against a hard surface, such as silicon or sapphire; which has the potential to significantly damage the tip. A recent method developed by Tourek et al. in 2010 involves deflecting the AFM Cantilever a known distance from the imaging tip by pressing the Cantilever against a sharpened tungsten wire. In this work a similar yet more precise method is described, whereby the deflection of the Cantilever is achieved using an AFM probe with a Spring constant much larger than the test Cantilever, essentially a rigid Cantilever. The exact position of loading on the test Cantilever was determined by reverse AFM imaging small spatial markers that are milled into the test Cantilever using a focussed ion beam. For V shaped Cantilevers it is possible to reverse image the arm intersection in order to determine the exact loading point without necessarily requiring FIB milled spatial markers, albeit at the potential cost of additional uncertainty. The technique is applied to tip-less, beam shaped and V shaped Cantilevers and compared to the hard surface contact technique with very good agreement (on average less than 5% difference). While the agreement with the hard surface contact technique was very good the error on the technique is dependent upon the assumptions inherent in the method, such as Cantilever shape, loading point distance and ratio of test to rigid Cantilever Spring constants. The average error ranged between 2 to 5% for the majority of test Cantilevers studied. The sensitivity derived with this technique can then be used to calibrate the Cantilever Spring constant using the thermal noise method, allowing complete force calibration to be accurately performed without tip-sample contact.
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Calibration of AFM Cantilever Spring constants.
Ultramicroscopy, 2003Co-Authors: Christopher T Gibson, Brandon L. Weeks, Chris Abell, Trevor Rayment, Sverre MyhraAbstract:In this paper we present two simple, reliable and readily applicable methods for calibrating Cantilevers and measuring the thickness of thin gold films. The Spring constant calibration requires knowledge of the Young's modulus, density of the Cantilever and resonant frequency. The thickness of thin gold layers was determined by measuring changes in the resonant frequency and Q-factor of beam shaped AFM Cantilevers before and after coating. The techniques for measuring the Spring constant and thin film thickness provide accuracy on the order of 10-15%.
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A nondestructive technique for determining the Spring constant of atomic force microscope Cantilevers
Review of Scientific Instruments, 2001Co-Authors: Christopher T Gibson, Brandon L. Weeks, Chris Abell, Jonathan R. I. Lee, Trevor RaymentAbstract:We present a simple, accurate, and nondestructive method to determine Cantilever Spring constants by measuring the resonant frequency before and after the addition of a thin gold layer. The method for resonating the Cantilevers uses electrostatic force modulation, which has been described for conductive Cantilevers, but we demonstrate it can also be applied to silicon nitride Cantilevers. The variations in Spring constant for Cantilevers of the same type across the same wafer are also explored.
Jon R Pratt - One of the best experts on this subject based on the ideXlab platform.
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experimental determination of mode correction factors for thermal method Spring constant calibration of afm Cantilevers using laser doppler vibrometry
Nanotechnology, 2013Co-Authors: Richard S. Gates, William A Osborn, Jon R PrattAbstract:Mode correction factors (MCFs) represent a significant adjustment to the Spring constant values measured using the thermal Cantilever calibration method. Usually, the ideal factor of 0.971 for a tipless rectangular Cantilever is used, which adjusts the value by 3% for the first flexural mode. An experimental method for determining MCFs has been developed that relies on measuring the areas under the first few resonance peaks for the flexural mode type. Using this method, it has been shown that MCFs for the first flexural mode of commercially available atomic force microscope Cantilevers actually vary from 0.95 to 1.0, depending on the shape and end mass of the Cantilever. Triangular shaped Cantilevers tend to lower MCFs with tipless versions providing the lowest values. Added masses (including tips) tend to increase the first flexural mode's MCF to higher values with large colloid probes at the high extreme. Using this understanding and applying it to the recently developed laser Doppler vibrometry thermal calibration method it is now possible to achieve very accurate and precise Cantilever Spring constant calibrations (uncertainties close to ±1%) with commonly available commercial Cantilevers such as tipped rectangular and triangular Cantilevers, and colloid probes.
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Accurate and precise calibration of AFM Cantilever Spring constants using laser Doppler vibrometry
Nanotechnology, 2012Co-Authors: Richard S. Gates, Jon R PrattAbstract:Accurate Cantilever Spring constants are important in atomic force microscopy both in control of sensitive imaging and to provide correct nanomechanical property measurements. Conventional atomic force microscope (AFM) Spring constant calibration techniques are usually performed in an AFM. They rely on significant handling and often require touching the Cantilever probe tip to a surface to calibrate the optical lever sensitivity of the configuration. This can damage the tip. The thermal calibration technique developed for laser Doppler vibrometry (LDV) can be used to calibrate Cantilevers without handling or touching the tip to a surface. Both flexural and torsional Spring constants can be measured. Using both Euler-Bernoulli modeling and an SI traceable electrostatic force balance technique as a comparison we demonstrate that the LDV thermal technique is capable of providing rapid calibrations with a combination of ease, accuracy and precision beyond anything previously available.
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small mass measurements for tuning fork based atomic force microscope Cantilever Spring constant calibration
2011Co-Authors: Gordon A Shaw, Jon R Pratt, Zeina J JabbourAbstract:Cutting edge mass sensors are capable of discriminating mass changes as small as several dozens of atoms, however the smallest mass commercially available from NIST with a calibration traceable to the International System of Units (SI) is 0.5 mg. To bridge this gap, new metrological techniques are being developed. A mass change from the electrochemical dissolution of tungsten wire has been measured using a commercial microbalance, and applied to a dynamic calibration of the Spring constant of a tuning fork oscillator designed for use in frequency modulated atomic force microscopy (FMAFM). The Spring constant measured using the dynamic method agreed within experimental uncertainty with that determined using an instrumented indenter, however an improved model for the indenter’s contact mechanics will be necessary to validate the assumptions used in the dynamic method to less than 10 %.
Richard S. Gates - One of the best experts on this subject based on the ideXlab platform.
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experimental determination of mode correction factors for thermal method Spring constant calibration of afm Cantilevers using laser doppler vibrometry
Nanotechnology, 2013Co-Authors: Richard S. Gates, William A Osborn, Jon R PrattAbstract:Mode correction factors (MCFs) represent a significant adjustment to the Spring constant values measured using the thermal Cantilever calibration method. Usually, the ideal factor of 0.971 for a tipless rectangular Cantilever is used, which adjusts the value by 3% for the first flexural mode. An experimental method for determining MCFs has been developed that relies on measuring the areas under the first few resonance peaks for the flexural mode type. Using this method, it has been shown that MCFs for the first flexural mode of commercially available atomic force microscope Cantilevers actually vary from 0.95 to 1.0, depending on the shape and end mass of the Cantilever. Triangular shaped Cantilevers tend to lower MCFs with tipless versions providing the lowest values. Added masses (including tips) tend to increase the first flexural mode's MCF to higher values with large colloid probes at the high extreme. Using this understanding and applying it to the recently developed laser Doppler vibrometry thermal calibration method it is now possible to achieve very accurate and precise Cantilever Spring constant calibrations (uncertainties close to ±1%) with commonly available commercial Cantilevers such as tipped rectangular and triangular Cantilevers, and colloid probes.
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Accurate and precise calibration of AFM Cantilever Spring constants using laser Doppler vibrometry
Nanotechnology, 2012Co-Authors: Richard S. Gates, Jon R PrattAbstract:Accurate Cantilever Spring constants are important in atomic force microscopy both in control of sensitive imaging and to provide correct nanomechanical property measurements. Conventional atomic force microscope (AFM) Spring constant calibration techniques are usually performed in an AFM. They rely on significant handling and often require touching the Cantilever probe tip to a surface to calibrate the optical lever sensitivity of the configuration. This can damage the tip. The thermal calibration technique developed for laser Doppler vibrometry (LDV) can be used to calibrate Cantilevers without handling or touching the tip to a surface. Both flexural and torsional Spring constants can be measured. Using both Euler-Bernoulli modeling and an SI traceable electrostatic force balance technique as a comparison we demonstrate that the LDV thermal technique is capable of providing rapid calibrations with a combination of ease, accuracy and precision beyond anything previously available.
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precise atomic force microscope Cantilever Spring constant calibration using a reference Cantilever array
Review of Scientific Instruments, 2007Co-Authors: Richard S. Gates, Mark ReitsmaAbstract:A method for calibrating the stiffness of atomic force microscope (AFM) Cantilevers is demonstrated using an array of uniform microfabricated reference Cantilevers. A series of force-displacement curves was obtained using a commercial AFM test Cantilever on the reference Cantilever array, and the data were analyzed using an implied Euler-Bernoulli model to extract the test Cantilever Spring constant from linear regression fitting. The method offers a factor of 5 improvement over the precision of the usual reference Cantilever calibration method and, when combined with the Systeme International traceability potential of the Cantilever array, can provide very accurate Spring constant calibrations.
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Direct measurement of Cantilever Spring constants and correction for Cantilever irregularities using an instrumented indenter.
The Review of scientific instruments, 2007Co-Authors: Z. Charles Ying, Mark Reitsma, Richard S. GatesAbstract:A method is presented that allows direct measurement of a wide range of Spring constants of Cantilevers using an indentation instrument with an integrated optical microscope. An uncertainty of less than 10% can be achieved for Spring constants from 0.1to102N∕m. The technique makes it possible to measure the Spring constant at any desired location on a Cantilever of any shape, particularly at the tip location of an atomic force microscopy Cantilever. The article also demonstrates a technique to detect and correct apparent length anomalies of Cantilevers by analyzing Spring constants at multiple positions.
Sun Shijun - One of the best experts on this subject based on the ideXlab platform.
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THE PASSIVE VIBRATION ISOLATION SYSTEMS AGAINST SEISMIC NOISE IN GRAVITATIONAL WAVE DETECTION
Advances in Mechanics, 2003Co-Authors: Sun ShijunAbstract:The passive vibration isolation systems against seismic noise for gravitational wave detectors are reviewed in this paper, including the principle of the isolators and the recent progresses in the field as well as the performances and characteristics of the isolators. Some low frequency passive isolators, such as the seven-stage gas Spring super- attenuator, the isolation stacks, the four-stage Cantilever Spring vibration isolator and the three- stage curved Cantilever Spring isolator, are shown to have a good isolation performance in the range above 10 Hz. Several ultra-low frequency horizontal vibration isolators, including the inverted pendulum system, the folded pendulum, the .X-pendulum, the conical pendulum, may have a resonant period of tens of seconds. The innovative prototype of the long period vertical vibration isolators based on torsion Spring, which eliminates the difficulty in a traditional mass-Spring vertical vibration isolator, provides an ultra-low frequency vertical vibration isolation.
W. J. Kaiser - One of the best experts on this subject based on the ideXlab platform.
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Electron Tunnel Sensors
Journal of Vacuum Science & Technology A: Vacuum Surfaces and Films, 1992Co-Authors: Thomas W. Kenny, J.k. Reynolds, W. J. Kaiser, J.a. Podosek, Howard K. Rockstad, E. C. Vote, Steven B. WaltmanAbstract:We have used the extreme sensitivity of electron tunneling to variations in electrode separation to construct a novel, compact displacement transducer. Electrostatic forces are used to control the separation between the tunneling electrodes, thereby eliminating the need for piezoelectric actuators. The entire structure is composed of micro-machined silicon single crystals, including a folded Cantilever Spring and a tip. Measurements of displacement sensitivity and noise are reported. Applications of this displacement transducer to the measurement of acceleration and infrared signals are discussed.
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Electron tunnel sensor technology
1991Co-Authors: Thomas W. Kenny, Steven B. Waltman, J.k. Reynolds, W. J. KaiserAbstract:Researchers designed and constructed a novel electron tunnel sensor which takes advantage of the mechanical properties of micro-machined silicon. For the first time, electrostatic forces are used to control the tunnel electrode separation, thereby avoiding the thermal drift and noise problems associated with piezoelectric actuators. The entire structure is composed of micro-machined silicon single crystals, including a folded Cantilever Spring and a tip. The application of this sensor to the development of a sensitive accelerometer is described.
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Micromachined silicon tunnel sensor for motion detection
Applied Physics Letters, 1991Co-Authors: Thomas W. Kenny, Steven B. Waltman, J.k. Reynolds, W. J. KaiserAbstract:We have used the extreme sensitivity of electron tunneling to variations in electrode separation to construct a novel, compact displacement transducer. Electrostatic forces are used to control the separation between the tunneling electrodes, thereby eliminating the need for piezoelectric actuators. The entire structure is composed of micromachined silicon single crystals, including a folded Cantilever Spring and a tip. Measurements of displacement sensitivity and noise are reported. This device offers a substantial improvement over conventional technology for applications which require compact, highly sensitive transducers.