Planar channeling and quasichanneling oscillations in a bent crystal

TL;DR

This paper investigates planar channeling and quasichanneling oscillations in bent crystals, revealing conditions for their occurrence and differences between positive and negative particles, with implications for accelerator applications.

Contribution

It introduces and characterizes a new type of quasichanneling oscillations, distinct from traditional channeling oscillations, through simulations and theoretical analysis.

Findings

Channeling oscillations observed only for positive particles.

Quasichanneling oscillations can exist for both positive and negative particles.

Conditions for experimental observation at existing accelerators are identified and optimized.

Abstract

Particles passing through a crystal under planar channeling experience transverse oscillations in their motion. As channeled particles approach the atomic planes of a crystal, they are likely to be dechanneled. This effect was used in ion-beam analysis with MeV energy. We studied this effect in a bent crystal for positive and negative particles within a wide range of energies in sight of application of such crystals at accelerators. We found the conditions for the appearance or not of channeling oscillations. Indeed a new kind of oscillations, strictly related to the motion of over-barrier particles, i.e. quasichanneling particles, has been predicted. Such oscillations, named planar quasichanneling oscillations, possess a different nature than channeling oscillations. Through computer simulation, we studied this effect and provided a theoretical interpretation for them. We show that channeling oscillations can be observed only for positive particles while quasichanneling oscillations can exist for particles with either sign. The conditions for experimental observation of channeling and quasichanneling oscillations at existing accelerators with available crystal has been found and optimized.