Development of an extended straightness measurement reference

Conference · Tue Sep 06 00:00:00 EDT 1988

OSTI ID:5041180

Schenz, R. F.; Griffith, L. V. ^[1]; Sommargren, G. E. ^[2]

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1. Lawrence Livermore National Lab., CA (USA)
2. Zygo Corp., Santa Cruz, CA (USA)

The most accurate diamond turning machines have used physical straightness references. These references commonly are made of optical materials, such as Zerodur, and are flat enough to permit straightness measurements with an accuracy of 100--150 nm (4--6 microinches) p-v. In most cases, the flatness error is stable and can be accommodated by using a calibration table. The straightedges for the Large Optics Diamond Turning Machine (LODTM) at Lawrence Livermore National Laboratory (LLNL) are 1.1 meters in length and allow a straightness reference accuracy of 25--50 nm (1--2 microinches) p-v after calibration. Fabrication problems become insurmountable when a straightness reference for a length of up to 4 meters is desired. Moreover, the method of calibration by straightedge reversal does not account for gravitational sag when the sensing direction is vertical. Vertical sensing would be required in a four meter system and sag would become unacceptably large. Recent developments published in the literature suggest that the use of a laser beam for a reference may be feasible. Workers at Osaka University have reported a laser beam straightness reference that has a resolution of 3.5 nm, although tests were done only over a 200 mm length. LLNL has begun an investigation on the use of a directionally stabilized laser beam as a straightness measurement reference. The goal of the investigation is to provide a reference that is accurate to 25 nm (1 microinch) over a four meter distance. 3 refs., 2 figs.

• Research Organization: Lawrence Livermore National Lab., CA (USA)
• Sponsoring Organization: DOE/DP
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5041180
• Report Number(s): UCRL-99540; CONF-8810335--2; ON: DE90006781
• Country of Publication: United States
• Language: English

Related Subjects

426001 -- Engineering-- Superconducting Devices & Circuits-- (1990-)
440800* -- Miscellaneous Instrumentation-- (1990-)
47 OTHER INSTRUMENTATION
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ACCURACY
CALIBRATION
CARBON
COHERENT SCATTERING
COMPUTERIZED SIMULATION
DIAMONDS
DIFFRACTION
ELEMENTAL MINERALS
ELEMENTS
FABRICATION
FUNCTIONS
GAUSS FUNCTION
LASERS
MACHINING
MEASURING INSTRUMENTS
MEASURING METHODS
MINERALS
NONMETALS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
REMOTE SENSING
SCATTERING
SIMULATION
STABILITY
TECHNOLOGY ASSESSMENT
VACUUM SYSTEMS