The steady-state temperature distribution in a thin anode bombarded by an electron beam field emitted from an individual multi-walled carbon nanotube is measured with an infrared camera, and this distribution is compared to that predicted by a numerical model. By assuming the electron distribution in the beam follows a Gaussian distribution, a good fit to the anode temperature profile is obtained and this fit provides an estimate of the beam spreading radius. Results indicate the electron beam narrows as the emission current increases. A heat flux on the anode surface as high as 0.35 W/cm(2) has been measured, corresponding to an electron beam radius of approximately 1.22 mm. (c) 2006 Elsevier Ltd. All rights reserved.