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Displaying 2526 - 2550 of 2737

Energy-pooling collisions in cesium: 6P/sub J/+6P/sub J/ to 6S+(nl=7P,6D,8S,4F)

January 1, 1996
Author(s)
Zeina J. Kubarych, S Milosevic, A Allegrini, J Huennekens, R K. Namiotka
We report experimental rate coefficients for the energy-pooling collisions Cs(6P/sub 1/2/)+Cs(6P/sub 1/2/) to Cs(6S/sub 1/2/)+Cs(nl/sub J''/) and Cs(6P/sub 3/2/)+Cs(6P/sub 3/2/) to Cs(6S/sub 1/2/)+Cs(nl/sub J''/) where nl/sub J''/=7P/sub 1/2/, 7P/sub 3/2/

Fabry-Perot Interferometers for Small Displacement Measurements

January 1, 1996
Author(s)
Lowell P. Howard, Fredric Scire, Jack A. Stone Jr.
A description of a Fabry-Perot interferometer for measuring small displacements is given. The instruments consists of a fiber-optic-coupled actuator and mirror guiding mechanisms, a tunable diode laser for tracking the changes in cavity length and a

Height Calibration of Atomic Force Microscopes Using Silicon Atomic Step Artifacts

January 1, 1996
Author(s)
V W. Tsai, Theodore V. Vorburger, P Sullivan, Ronald G. Dixson, Richard M. Silver, Edwin R. Williams, J Schneir
The decreasing feature dimensions required in the semiconductor manufacturing industry are placing ever increasing demands upon metrology instruments. Atomic force microscopes (AFMs), which can have 1 nm lateral resolution and sub-angstrom vertical

Integral Equation for Scattering by a Rough Surface

January 1, 1996
Author(s)
Egon Marx
An equation for an unknown surface field that represents scattering by a rough patch on a flat dielectric surface is presented. The geometrical considerations for this particular problem are discussed, especially in relation to a surface divergence factor.

New NIST-Certified Length Microscale

January 1, 1996
Author(s)
James E. Potzick
The National Institute of Standards and Technology is developing a simple one-dimension certified pitch standard (or scale) covering the range 1 um to 10 mm, intended for the calibration of microscope magnification and dimensional metrology instrument

Novel Methods for Length Measurement Employing Diode Lasers

January 1, 1996
Author(s)
Jack A. Stone Jr., Lowell P. Howard, Alois Stejskal, M Stephens, C Oates, L Hollberg
Diode lasers have several unique capabilities for length-measurement applications, arising from properties of the diodes that are much different from those of the venerable helium-neon laser presently used for most interferometric measurements. For example

Optical Overlay Metrology at NIST

January 1, 1996
Author(s)
Richard M. Silver, Amy Singer, L Carroll, S Berg-cross, James E. Potzick
Many of the significant challenges in making accurate overlay registration measurements are discussed. An understanding of the causes of the errors affecting these measurements is a prerequisite to improving accuracy and also for the design of standard

Progress Towards Accurate Metrology Using Atomic Force Microscopy

January 1, 1996
Author(s)
T Mcwaid, J Schneir, John S. Villarrubia, Ronald G. Dixson, V W. Tsai
Accurate metrology using atomic force microscopy (AFM) requires accurate control of the tip position, an estimate of the tip geometry, and an understanding of the tip-surface interaction forces. We describe recent progress at NIST towards accurate AFM

Relativistic Covariance and the Interpretation of Quantum Mechanics

January 1, 1996
Author(s)
Egon Marx
The standard interpretation of quantum mechanics is revised to conform to the relativistic theory based on the many-amplitudes formalism for the N-particle system. The wave function acquires a significance closer to that of the electromagnetic field, with

Self-Calibration: Reversal, Redundancy, Error Separation, and "Absolute Testing"

January 1, 1996
Author(s)
Christopher J. Evans, R Hocken, William T. Estler
Over the years many techniques have been developed for accurate measurement of part features without reference to an externally calibrated artifact. This paper presents a partial survey of such methods for dimensional metrology, their ranges of application

SEM Image Sharpness Analysis

January 1, 1996
Author(s)
Michael T. Postek, Andras Vladar
The technique described here, utilizing the sharpness concept, is facilitated by the use of the FFT techniques to analyze the electron micrograph to obtain the evaluation. This is not the first application of Fourier techniques to SEM images, but it is the

Statistical Models for Estimating the Measurement of Pitch in Metrology Instruments

January 1, 1996
Author(s)
Nien F. Zhang, Michael T. Postek, Robert D. Larrabee
The measurement of pitch in metrology instruments is through to be a benign self-compensating function. In the course of issuing the new scanning electron microscope standard SRM 2090, a new algorithm for the measurement of pitch was developed. This is

Strut Structure and Rigid Joint Therefor

January 1, 1996
Author(s)
James E. Potzick
A highly rigid structure is provided using six struts connected at three upper and three lower nodes to upper and lower support structures. The joint assemblies are formed by half- spherical balls attached to the ends of each of the struts, and retained

Stylus Flight in Surface Profiling

January 1, 1996
Author(s)
Jun-Feng Song, Theodore V. Vorburger
In this paper, theoretical and experimental work on stylus flight is described. Experiments on the surfaces of different roughness specimens with sinusoidal, rectangular, triangular and random waveforms support the theoretical model, which predicts stylus

Uncertainty Procedure for NIST Surface Finish and Microform Calibration

January 1, 1996
Author(s)
Jun-Feng Song, Theodore V. Vorburger
An uncertainty procedure is used for reporting the NIST surface finish and microform calibration uncertainties. The combined standard uncertainty is a combination of the uncertainty from the geometric non-uniformity of the measured surface, and the

Using a Potentiostat to Model In-Process Electromechanical Dressing

January 1, 1996
Author(s)
Robert S. Polvani, A Fraker, Christopher J. Evans
In-process electrochemical dressing insures true, sharp, stable wheels for efficient ceramic grinding. To better implement electrochemical dressing, we couple laboratory studies based on a potentiostat with shop floor grinding runs. To do this, a calomel

Wavelength-Shift Interferometry: Using a Dither to Improve Accuracy

January 1, 1996
Author(s)
Jack A. Stone Jr., Alois Stejskal, Lowell P. Howard
A dither in path length can dramatically improve the accuracy of wavelength-shift methods used for absolute distance interferometry. Here we report how a dither improves the accuracy of absolute distance measurement by two orders of magnitude, reducing

Visualization of Surface Figure Using Zernike Polynomials

December 1, 1995
Author(s)
Christopher J. Evans, R E. Parks, P Sullivan, John S. Taylor
Commercial software in modern interferometers used in optical testing frequently fit the wave-front or surface-figure error to Zernike polynomials; typically 37 coefficients are provided. We provide visual representations of these data in a form that may

Stylus Technique for Direct Verification of Rockwell Diamond Indenters

November 23, 1995
Author(s)
Jun-Feng Song, F Rudder, Theodore V. Vorburger, J Smith
Based on a stylus technique, a microform calibration system was developed at NIST for the direct verification of Rockwell diamond indenters. The least-squares radius and profile deviations, cone angle and cone flank straightness, and the holder axis
Displaying 2526 - 2550 of 2737
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