Temperature Gradients in the Targets During High-Intensity Implantation in Forced Cooling

High-intensity ion implantation - new instrument for deep modification of the elemental composition and microstructure of metallic materials. Low-energy ion implantation is accompanied by a significant increase in the temperature of the target at ion current densities of tens and hundreds of milliamps per square centimeter. The negative effects of increasing temperature, such as grain growth of the target crystal structure, can be eliminated by post-implantation impact on the ion-doped layer (for example, a pulsed high-current electron beam). To implement this approach successfully, it is important to determine the parameters and modes of ion irradiation including heat removal conditions by using a massive target holder or forced cooling of the nonirradiated side of the target in which the temperature value in the ion-doped layer will correspond to the conditions of radiation-stimulated diffusion of the implanted element and the temperature in matrix material will not lead to significant grain growth. The work is devoted to the study of the temperature gradient formation on the surface and over the depth of metal targets during the high-intensity ion implantation. The results of numerical simulation of the dynamic and gradient characteristics of temperature fields in metal targets with different thermal conductivity during high-intensity ion implantation are presented. The gradients of temperature fields under the influence of repetitively pulsed ion beams were studied. The laws of temperature field variation over the target depth are described depending on the target material, its geometric dimensions and heat removal conditions including during forced cooling to the cryogenic temperatures of the back side of the sample.