title: Growth problems of sapphire and ruby of optical quality.
abstract: A careful analysis of the basic mechanisms of the Verneuil process led to a methodical study of the many parameters associated with it. Among these, the feed rate, retraction rate, and flame characteristics were found to be most important. A photoelectric cell as the sensor for a servo system with two outputs was used to sense the plane of crystallization and control its position. A completely automated Verneuil apparatus, incorporating this and other control systems, suitable for the study of growth under well-defined, rigidly controlled, and dependably reproducible conditions was designed and constructed.
authors.affiliation: Willow Run Laboratories, the Institute of Science and Technology, The University of Michigan, Ann Arbor, Michigan 48107, USA.
authors.forename: F A
authors.initials: FA
authors.lastname: Reiss