Proton channeling in NaCl simulation of channeling and x-ray excitation

Publisher Website
Google Scholar
Abstract
In alkali halide crystals two classes of directions can confront a particle beam in a channeling experiment. Some directions (〈100〉 e.g.) contain alternating cations and anions while others (〈110〉 e.g.), composed of only cations or anions, alternate in the crystal. The channeling of 75 keV protons and their (K) x-ray production along 〈110〉 and 〈110〉 has been investigated by a computer simulation in NaCl at 80°C and 280°C for Comparison with measurements of x-ray channeling dips. The simulation included thermal lattice vibrations, impact parameter dependent electronic energy loss and (K) x-ray excitation. Along 〈100〉 the normalized x-ray yield profiles for Na(K) and Cl(K) are identical within the statistics of the computations and agree with the dechannelled fraction for small incident angles. But, along 〈110〉 more Na(K) than Cl(K) x-rays are produced (normalized to the respective random yields), in accord with our result that dechanneling occurs mainly at Na rows owing to their weaker row potentials.