Effective calculation of laser stripping via a broad shape resonance

Abstract

This paper presents the theory and method of calculation of laser assisted charge exchange injection via a broad shape resonance of the hydrogen atom with a new level of accuracy. The method is optimized for fast calculations, needed for practical estimations of laser-stripping efficiency for charge exchange injection. The novelty is that we take into account the resonance width and continuous spectrum of the hydrogen atom in our model. As a result we show that the broad shape resonance can fully compensate the Doppler broadening of the laser frequency in realistic beams without applying laser chirp and increasing laser power. The resulting scheme can be realized by applying a magnetic field of optimal strength to the high-energy beam irradiated by laser field. Another novelty is that we use the temporal Schrödinger equation as the basis of our model in contrast with the existing method of semiempirical cross sections, which is widely considered in atomic physics. The strict quantum mechanical approach gives the temporal evolution of the wave function and the ionization probability of the hydrogen atom as a function of laser and static electric fields. Moreover, it reveals quantum effects at the strong laser field which cannot be described with the cross section treatment. It is shown that the effects play a significant role in the optimization of the magnetic field for the laser-stripping scheme.

Dynamics of uncaught foil-stripped electrons in the Oak Ridge Spallation Neutron Source accumulator ring

“…The process of foil stripping at high beam power poses a number of challenges, including foil heating and foil stability, beam scattering, transport of waste beams, and disposal of stripped electrons. Recently, a great deal of attention has been paid to the development of novel stripping techniques [2,3], and to the fabrication of more resilient foils [4,5]. Less effort has been dedicated to understanding the dynamics of the foil-stripped electrons, especially in operational machines.…”