Environmental effects on registration and accuracy data on quartz photomasks utilizing the LMS-2000 laser metrology system

1990 ◽  
Author(s):  
Larry E. Land ◽  
John M. Whittey
Keyword(s):  
Environmental Effects ◽  
Laser Metrology ◽  
Accuracy Data ◽  
Metrology System

Active figure maintenance control using an optical truss laser metrology system for a space-based far-IR segmented telescope

1992 ◽  
Author(s):  
Kenneth H. Lau ◽  
William G. Breckenridge ◽  
Noble M. Nerheim ◽  
David C. Redding
Keyword(s):  
Laser Metrology ◽  
Metrology System

scholarly journals The Baseline Metrology System of the USNO Astrometric Interferometer

1994 ◽  
Vol 158 ◽  
pp. 174-176 ◽  
Author(s):  
Nicholas M. Elias ◽  
Donald J. Hutter
Keyword(s):  
High Resolution ◽  
Northern Hemisphere ◽  
Three Dimensional ◽  
Optical Interferometer ◽  
Laser Metrology ◽  
Under Construction ◽  
Metrology System ◽  
Better Than

The USNO Astrometric Interferometer (USNOAI; a subarray of the Navy Prototype Optical Interferometer at Lowell Observatory) is presently under construction and expected to begin limited operations within a year. The main goal of the USNOAI observations is to provide a northern hemisphere catalog of several thousand stars with positions known to a few mas. In order to meet this requirement, a baseline laser metrology system must be employed to measure the three-dimensional motions of the baselines with an accuracy better than ~ 0.1 μm. The metrology scheme, as presently conceived, represents the largest and most complex high-resolution laser metrology system ever attempted.

scholarly journals Laser interferometric high-precision geometry (angle and length) monitor for JASMINE

2007 ◽  
Vol 3 (S248) ◽  
pp. 280-281
Author(s):  
Y. Niwa ◽  
K. Arai ◽  
A. Ueda ◽  
M. Sakagami ◽  
N. Gouda ◽  
...  
Keyword(s):  
Wave Front ◽  
High Precision ◽  
Small Scales ◽  
Laser Metrology ◽  
Laser Interferometric ◽  
Metrology System

AbstractThe telescope geometry of JASMINE should be stabilized and monitored with the accuracy of about 10 to 100 pm or 10 to 100 prad of rms over about 10 hours. For this purpose, a high-precision interferometric laser metrology system is employed. Useful techniques for measuring displacements on extremely small scales are the wave-front sensing method and the heterodyne interferometrical method. Experiments for verification of measurement principles are well advanced.

scholarly journals The USNO Astrometric Interferometer

1994 ◽  
Vol 158 ◽  
pp. 427-435
Author(s):  
Donald J. Hutter
Keyword(s):  
State Of The Art ◽  
Naval Research ◽  
Delay Lines ◽  
Optical Interferometer ◽  
Zeroth Order ◽  
Matching Accuracy ◽  
Naval Observatory ◽  
Laser Metrology ◽  
Fringe Tracking ◽  
Metrology System

The U.S. Naval Observatory Astrometric Interferometer (USNOAI) will be the dedicated astrometric sub-array of the new Navy Prototype Optical Interferometer (NPOI) at Lowell Observatory, which is being built in collaboration with the Naval Research Laboratory. The USNOAI will be in operation on Anderson Mesa, near Flagstaff, Arizona, in late 1993. The instrument will incorporate four siderostats which will be located in a Y-shaped configuration, and will feature state-of-the-art delay lines, a real-time zeroth-order fringe tracking algorithm, a full-array laser metrology system to monitor baseline motion, and a limiting magnitude of 10. The instrument will be capable of simultaneous observations on six baselines, and will produce star positions accurate to a few mas. With it, we will be able to maintain the HIPPARCOS reference frame with matching accuracy over the next few decades.

Development of ITER In-Vessel Viewing and Metrology Systems

1998 ◽  
Vol 10 (2) ◽  
pp. 96-103
Author(s):  
Kenjiro Obara ◽  
◽  
Satoshi Kakudate ◽  
Masataka Nakahira ◽  
Akira Ito
Keyword(s):  
High Temperature ◽  
Gamma Radiation ◽  
Technology Development ◽  
High Vacuum ◽  
Inert Gas ◽  
Design And Technology ◽  
Home Team ◽  
Laser Metrology ◽  
Metrology System ◽  
The U.S

The ITER in-vessel viewing system is vital for detecting and locating damage to in-vessel components such as the blankets and divertors and in monitoring and assisting in-vessel maintenance. This system must be able to operate at high temperature (200°C) under intense gamma radiation (-30 kGy/h) in a high vacuum or I bar inert gas. A periscope viewing system was chosen as a reference due to its clear, wide view and a fiberscope viewing system chosen as a backup for viewing in narrow confines. According to the ITER R&D program, both systems and a metrology system are being developed through the joint efforts of Japan, the U.S., and RF Home Teams. This paper outlines design and technology development mainly on periscope in-vessel viewing and laser metrology contributed by the Japan Home Team.

scholarly journals The USNO Astrometric Optical Interferometer

1995 ◽  
Vol 166 ◽  
pp. 23-29
Author(s):  
D.J. Hutter ◽  
K.J. Johnston ◽  
D. Mozurkewich
Keyword(s):  
State Of The Art ◽  
Tracking System ◽  
Proper Motions ◽  
Optical Interferometer ◽  
Naval Observatory ◽  
Operational Lifetime ◽  
Visual Magnitude ◽  
Laser Metrology ◽  
Fringe Tracking ◽  
Metrology System

The U.S. Naval Observatory Astrometric Optical Interferometer (AOI) began operation on Anderson Mesa, near Flagstaff, Arizona, in the autumn of 1994. The AOI incorporates four siderostats that are located in a Y-shaped configuration, and features a full-array laser metrology system to monitor baseline motion. The AOI incorporates state-of-the-art delay lines and a real-time fringe-tracking system. The AOI will have a limiting visual magnitude of 10, under typical observing conditions, and will produce star positions accurate to a few milliarcseconds (mas). With a planned operational lifetime of several decades, this instrument will be capable of maintaining the optical reference frame by improving the proper motions of thousands of the brighter HIPPARCOS stars through repeated observations.

Imaging molecules adsorbed onto electrodes under potential control by scanning probe microscopy

1991 ◽  
Vol 49 ◽  
pp. 376-377 ◽  
Author(s):  
N.J. Tao ◽  
J.A. DeRose ◽  
P.I. Oden ◽  
S.M. Lindsay
Keyword(s):  
Surface Charge ◽  
Environmental Effects ◽  
Scanning Probe Microscopy ◽  
Statistical Significance ◽  
Electrochemical Methods ◽  
Surface Structures ◽  
Scanning Probe ◽  
Potential Control ◽  
Afm Imaging ◽  
Special Circumstances

Clemmer and Beebe have pointed out that surface structures on graphite substrates can be misinterpreted as biopolymer images in STM experiments. We have been using electrochemical methods to react DNA fragments onto gold electrodes for STM and AFM imaging. The adsorbates produced in this way are only homogeneous in special circumstances. Searching an inhomogeneous substrate for ‘desired’ images limits the value of the data. Here, we report on a reversible method for imaging adsorbates. The molecules can be lifted onto and off the substrate during imaging. This leaves no doubt about the validity or statistical significance of the images. Furthermore, environmental effects (such as changes in electrolyte or surface charge) can be investigated easily.

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