Channeling of protons through carbon nanotubes

TL;DR

This paper provides a comprehensive theoretical analysis of proton channeling through carbon nanotubes, focusing on the crystal rainbow effect, angular distributions, and the influence of dynamic polarization, supported by computer simulations.

Contribution

It introduces the detailed theory of crystal rainbows in nanotube proton channeling and analyzes the impact of dynamic polarization on proton distributions.

Findings

Rainbow patterns explain angular distributions of channeled protons.

Dynamic polarization significantly affects proton transmission distributions.

Rainbow cycles describe the evolution of angular distributions with nanotube length.

Abstract

This book contains a thorough theoretical consideration of the process of proton channeling through carbon nanotubes. We begin with a very brief summary of the theoretical and experimental results of studying ion channeling through nanotubes. Then, the process of ion channeling is described briefly. After that, the crystal rainbow effect is introduced. We describe how it was discovered, and present the theory of crystal rainbows, as the proper theory of ion channeling in crystals and nanotubes. We continue with a description of the effect of zero-degree focusing of protons channeled through nanotubes. It is shown that the evolution of the angular distribution of channeled protons with the nanotube length can be divided in the cycles defined by the rainbow effect. Further, we analyze the angular distributions and rainbows in proton channeling through nanotubes. This is done using the theory of crystal rainbows. The angular distributions are generated by the computer simulation method, and the corresponding rainbow patterns are obtained in a precise analysis of the mapping of the impact parameter plane to the transmission angle plane. We demonstrate that the rainbows enable the full explanation of the angular distributions. We also investigate how the effect of dynamic polarization of the carbon atoms valence electrons influences the angular and spatial distributions of protons transmitted through short nanotubes in vacuum and embedded in dielectric media. In addition, we explore the channeling star effect in 1 GeV proton channeling through bundles of nanotubes, which appears when the proton beam divergence angle is larger than the critical angle for channeling.