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Proceedings Paper

Camber measurement in quality control of beryllia capillary tubes for argon ion lasers
Author(s): John N. Pike; Alfred M. Gaibrois; James F. Lynch
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Paper Abstract

Ion lasers commonly make use of BeO beam tubes because of favorable electrical insulation and high heat conduction properties. The bore along the axis of such a ceramic tube is precisely controlled to length diameter and end-toend straight ness specification tolerances to obtain desired system performance. The capillary''s ma. imum departure from true straight (camber) correlates inversely with lasing eff i ciency. We report here a simple non-contact method and instrument for measuring camber an extension of qual i tative visual inspection practice . A diffusely ii luminated occulting stop is projected so as to almost fill the entrance end of a capil lary. Multiple internal reflections produce a manifold of reasonably sharp concentric virtual rings. We show how qrazinq incidence (paraxial) meridional ray reflec tion optics relates observed nonconcentricity of the first ring to capillary camber. For capillary dimensions of interest (13 mm diameter 8-50 cm lenqth) the sensitivity of camber measurement is approximately 1 mil ( 025 mm). Polaroid pho toqraphy is currently used to record images for camber determination the method lends itself to automation through the use of a CCD camera whereby laser tubes could be inspected serially or in batches. 1.

Paper Details

Date Published: 1 August 1990
PDF: 11 pages
Proc. SPIE 1266, In-Process Optical Measurements and Industrial Methods, (1 August 1990); doi: 10.1117/12.20257
Show Author Affiliations
John N. Pike, J. J. Pike & Co., Inc. (United States)
Alfred M. Gaibrois, Materials Research Corp. (United States)
James F. Lynch, General Ceramics Inc. (United States)

Published in SPIE Proceedings Vol. 1266:
In-Process Optical Measurements and Industrial Methods
H. A. Macleod; Peter Langenbeck, Editor(s)

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