Short-period arc-discharge for growing carbon nanotubes has been investigated to study the cooling effect of the arc plasma region. The yield of carbon nanotubes strongly depends on the cooling rate. At the optimum cooling condition using helium gas, nanotubes were grown on both the anode and the cathode. The optical emission spectra from the arc plasma indicate that the plasma temperature increases at the optimum cooling rate. (C) 2004 Elsevier B.V. All rights reserved.