Analysis of the low gravity tolerance of Bridgman-Stockbarger crystal growth II. Transient and periodic accelerations

Academic Article

Abstract

  • The effects of single and multicomponent oscillatory residual accelerations on dopant distribution in gallium-doped germanium crystals grown by the Bridgman-Stockbarger technique is investigated numerically. The multicomponent disturbances include three-component accelerations and complex acceleration profiles synthesized from Fourier analyses of acceleration data obtained on the Spacelab-3 (SL-3) mission. We find that the largest compositional nonuniformities occur for disturbances with amplitudes above 10-6 g and frequencies below 10-2 Hz. At higher frequencies, larger acceleration amplitudes are required to obtain significant nonuniformities. These nonuniformities are barely detectable at early times, reach a maximum after the velocity transient and subsequently decrease over the characteristic concentration diffusion time. The effect of several "g-jitter" profiles synthesized from SL-3 measurements with frequencies between 10-1-10 Hz is examined. The system is found to exhibit marginal sensitivity to only one of these acceleration profiles. © 1991.
  • Digital Object Identifier (doi)

    Author List

  • Alexander JID; Amiroudine S; Ouazzani J; Rosenberger F
  • Start Page

  • 21
  • End Page

  • 38
  • Volume

  • 113
  • Issue

  • 1-2