Multiple ionization cross-sections of rare gas atoms by impact of highly charged particles at 35 MeV/a.m.u.

Production of multiply charged recoil ions by impact of swift highly charged projectiles is investigated. The first Born Plane Wave Approximation employed in the framework of the independent electron model (IEM) provides reasonable cross-sections for multiple ionization of rare gases by Krq+ (q ∼ 30) at 35 MeV/amu, which is a typical ion beam on the LISE ( 1) line at GANIL. Contribution of capture is investigated in the case of helium target.La production d'ions de recul multichargés obtenus par impact d'ions lourds rapides et très chargés est étudiée. L'approximation de l'onde plane de Born au premier ordre, employée dans le cadre du modèle à électrons indépendants, fournit des sections efficaces d'ionisation multiple raisonnables pour des gaz rares, bombardés par du Krq+ , (q∼30 ) à 35 MeV/u.m.a., qui est un faisceau typique disponible sur LISE ( 1) à GANIL. La contribution de la capture a été estimée dans le cas d'une cible d'hélium

SOFT X-RAY SPECTROSCOPY OF ARGON RECOIL IONS

Radiation from argon with wavelength 8-85 nm has been measured with a grazing incidence spectrometer after excitation by 0.7 MeV/amu Cl11+ and 0.35 Mev/amu Cl9+ and Br14+. 417 lines have been identified. With a pulsed beam the radiation has been sorted into prompt and delayed fractions. Decay time analysis for separate peaks is correlated to charge state of the recoil ion. This leads especially to good assignment of Ar VII and Ar VIII lines. Delayed spectra do not depend much on projectile charge and velocity