Radiation interactions are of importance in crystal pullers for growing crystals from melts since these operate at very high temperatures. The radiation view factors change at various stages of crystal growth, and accurate modeling requires tracking of these at various stages of cooling. For short crystals it may turn out that the (colder) crystal surface is actually gaining heat (from radiation from the hot melt surface) instead of losing it, thereby affecting the rate of solidification. You will need to be able to compute the various view factors and the radiation interactions at various stages of the growth with the background material presented in this chapter and suggest proper cooling strategies at various stages of the crystal growth. The paper of Srivastava et al. (1986) is useful as an additional source here.