Electron loss cross sections of fluorine negative-ion projectile for modeling of inertial confinement fusion

Abstract

Negative ion beams have been proposed as drivers for inertial confinement fusion (ICF), as high-velocity neutral projectiles produced by photodetachment may efficiently impact and heat up a hydrogen pellet target. Charge-changing cross sections are henceforth needed to estimate the beam attenuation in the residual gases. In this work we analyse cross section measurements for the several electron-loss collision channels of fluorine anions impinging on argon (10-50 keV/u energy range) and producing charge states from Ar + to Ar 4+ . Cross sections for projectile destruction associated to target ionization rise steeply with velocity, displaying a clear energy threshold. This threshold is characteristic of a collision process involving direct interaction between a projectile electron and a target electron.