Recoil Analysis for Heavy Ion Beams

TL;DR

This study computes recoil values for various heavy ion beams in water phantoms using Monte Carlo simulations, revealing patterns in recoil peak amplitudes and structural gaps that vary with ion type and energy.

Contribution

It introduces a detailed analysis of recoil effects for boron, carbon, nitrogen, and oxygen beams in water, expanding understanding of ion interactions in heavy ion therapy.

Findings

Recoil peak amplitude increases regularly for carbon and boron ions.

Oxygen and nitrogen do not show regular recoil amplitude patterns.

Crystal structure gaps increase with energy for all studied ions.

Abstract

Given that there are 94 clinics and more than 200,000 patients treated worldwide, proton and carbon are the most used heavily charged particles in heavy ion therapy. However, there is a recent increasing trend in using new ion beams. Each heavy ion has a different effect on the target. As each heavy ion moves through the tissue, they lose enormous energy in collisions, so their range is not long. Ionization accounts for the majority of this loss in energy. During this interaction of the heavily charged particles with the target, the particles do not only ionize, but also lose energy with the recoil. Recoil occurs by atom-to-atom collisions. With these collisions, crystalline atoms react with different combinations and form cascades in accordance with their energies. Thus, secondary particles create ionization and recoil. In this study, recoil values of boron, carbon, nitrogen and oxygen beams in the water phantom were computed in the energy range of 2.0-2.5 GeV using Monte Carlo simulation and the results were compared with carbon. It was observed that there is a regular increase in the recoil peak amplitude for carbon and boron ions, unlike oxygen and nitrogen where such a regularity could not be seen. Moreover, the gaps in the crystal structure increased as the energy increases.