Cascade emission in electron beam ion trap plasma of W25+ ion

Abstract

Spectra of the W25+ ion are studied using the collisional-radiative model (CRM) with an ensuing cascade emission. It is determined that the cascade emission boosts intensities only of a few lines in the 10–30nm range. The cascade emission is responsible for the disappearance of structure of lines at about 6nm in the electron beam ion trap plasma. Emission band at 4.5–5.3 nm is also affected by the cascade emission. The strongest lines in the CRM spectrum correspond to 4d94f4→4f3 transitions, while 4f25d→4f3 transitions arise after the cascade emission is taken into account.