This investigation explores the effect of crystal cooling rate upon minority carrier lifetime over the range 50 C/min to 600 C/min, using float-zone (FZ) growth as a vehicle. The crystal cooling rate dT/dt is a product of two factors: axial thermal gradient dT/dx, and growth rate dx/dt. A motivation for this work is to gain insight into the observed differences in minority carrier lifetime between silicon ribbons (Tis short) and FZ crystals (r is long). for ribbons is observed to usually increase if the ribbons are heated from room temperature to approximately 1000 C and cooled slowly. During crystal growth, there is a large difference between the cooling rates of ribbons and ingots due to two factors: dT/dx and dx/dt are both large for ribbons (> 200 C/cm and> 2 but small for ingots (< 140 C/cm and 400 C/min for ribbons and< 70 C/min for ingots. Hence, there may be a dependence of minority carrier lifetime upon crystal cooling rate following solidification. cm/min)