Several 100 MeV/u heavy ions and a crystal target 1. Two dimensional resonant coherent excitation

A fast ion passing through a crystal periodically traverse constituent atoms, atomic rows and even atomic planes. The ions may be resonantly excited using an oscillating electric field that the ions feel, which is called coherent resonance excitation (RCE). By using heavy ions in the relativistic energy region in HIMAC, a detailed resonant excitation spectrum can be obtained. In this paper, we explain the significance of two-dimensional RCE (2D-RCE) phenomenon under planar channeling conditions together with the background. (author)