NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Temperature and melt solid interface control during crystal growthFindings on the adaptive control of a transparent Bridgman crystal growth furnace are summarized. The task of the process controller is to establish a user specified axial temperature profile by controlling the temperatures in eight heating zones. The furnace controller is built around a computer. Adaptive PID (Proportional Integral Derivative) and Pole Placement control algorithms are applied. The need for adaptive controller stems from the fact that the zone dynamics changes with respect to time. The controller was tested extensively on the Lead Bromide crystal growth. Several different temperature profiles and ampoule's translational rates are tried. The feasibility of solid liquid interface quantification by image processing was determined. The interface is observed by a color video camera and the image data file is processed to determine if the interface is flat, convex or concave.
Document ID
19900017348
Acquisition Source
Legacy CDMS
Document Type
Contractor Report (CR)
Authors
Batur, Celal
(Akron Univ. Akron, OH, United States)
Date Acquired
September 6, 2013
Publication Date
July 1, 1990
Subject Category
Solid-State Physics
Report/Patent Number
NAS 1.26:186731
NASA-CR-186731
Accession Number
90N26664
Funding Number(s)
CONTRACT_GRANT: NCC3-109
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
No Preview Available