A note on the radiative energy loss from an ion-bombarded surface

It has recently been argued that the heat radiation from spikes, according to the Stefan-Boltzmann law, plays an important role in thermal behaviour of a copper target bombarded with 100keV Xe⁺ ions. In this work we have monitored the temperature evolution of a copper bar subjected to a 40 keV N⁺, Xe⁺, Sb₂ ⁺, and a 20 keV Sb⁺ ion bombardment. Our measurements have not revealed any substantial differences between light and heavy ion bombardment as well as between atomic and molecular implantation. Those results are in agreement with the time constant for radiation being long, of order 10⁻⁶s. They also agree with the calculations of the radiative energy loss from the spike, based upon both cylindrical and spherical spike models. In all reported cases, the energy lost from the spike via the heat radiation, although much different for different projectiles, is smaller than 1% of the ion deposited energy and its influence on the target temperature evolution lies within uncertainty of a typical ion current measurement. This work was carried out as a part of Research Project CPBP 01.09