Patents

United States Patent 4,302,280

Bruni November 24, 1981

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Growing gadolinium gallium garnet with calcium ions

Abstract

Monocrystalline gadolinium gallium garnet is prepared by the Czochralski growth process from a melt composed of the oxides of gadolinium and gallium. In order for this process to produce uniform crystal growth, the growing crystal must support a meniscus of liquid above the level of the surrounding melt. This meniscus is held up by the surface tension between the liquid and the growing crystal. It has been established that impurities in the meniscus region lower the surface tension of the liquid phase causing the meniscus to lose contact with the solid phase resulting in nonuniform crystal growth. By the addition of approximately 100 ppm of calcium into the melt, a counteracting effect is produced causing the meniscus to remain in contact with the growing crystal.

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Inventors:        Bruni; Frank J. (Charlotte, NC)

Assignee:         Texas Instruments Incorporated (Dallas, TX)

Family ID:       26803546

Appl. No.:       06/106,321

Filed:   December 21, 1979

 

United States Patent 5,660,627

Manente , et al.          August 26, 1997

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Method of growing lutetium oxyorthosilicate crystals

Abstract

A method for producing lutetium oxyorthosilicate crystals includes maintaining the interface between a crystal and the melt from which it is pulled substantially flat as the crystal is grown. In a Czochralski growth method, the rate of rotation of the crystal and its diameter are typically controllable to provide the flat interface as the crystal is pulled. Crystals produced by this method exhibit less variability in scintillation behavior so making them particularly suitable for spectroscopic uses. Such crystals find uses in borehole logging tools.

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Inventors:        Manente; Ralph A. (Monroe, CT), Bruni; Frank (Santa Rosa, CA), Melcher; Charles L. (West Redding, CT), Peterson; Carl A. (Yonkers, NY), Schweitzer; Jeffrey S. (Ridgefield, CT)

Assignee:         Schlumberger Technology Corporation (New York, NY)

Family ID:       23288115

Appl. No.:       08/330,051

Filed:   October 27, 1994