Journal article

Publication year: 2016

Journal: Journal of Physics B: Atomic, Molecular and Optical Physics

Volume number: 49

Issue number: 8

ISSN: 0953-4075

eISSN: 1361-6455

Open access status: Green

DOI Link: https://doi.org/10.1088/0953-4075/49/8/084006

Publisher: IOP Publishing

Abstract: 
We have measured electron impact ionization (EII) for Fe8+ forming Fe9+ from below the ionization threshold to 1200 eV. These measurements were carried out at the TSR heavy ion storage ring. The objective of using a storage ring is to store the ion beam initially so that metastable levels decay, thereby allowing for measurements on a well-defined ground-level ion beam. In this case, however, some metastable levels were too long lived to be removed. We discuss several methods for quantifying the metastable fraction, which we estimate to be similar to 30%-40%. Although metastables remain problematic, the present storage ring work improves upon other experimental geometries by limiting the metastable contamination to only a few long-lived excited levels. We discuss some future prospects for obtaining improved measurements of Fe8+ and other ions with long-lived metastable levels.

Harvard Citation style: Hahn, M., Becker, A., Bernhardt, D., Grieser, M., Krantz, C., Lestinsky, M., et al. (2016) Storage ring cross section measurements for electron impact ionization of Fe⁸⁺, Journal of Physics B: Atomic, Molecular and Optical Physics, 49(8), Article 084006. https://doi.org/10.1088/0953-4075/49/8/084006

APA Citation style: Hahn, M., Becker, A., Bernhardt, D., Grieser, M., Krantz, C., Lestinsky, M., Mueller, A., Novotny, O., Pindzola, M., Repnow, R., Schippers, S., Spruck, K., Wolf, A., & Savin, D. (2016). Storage ring cross section measurements for electron impact ionization of Fe⁸⁺. Journal of Physics B: Atomic, Molecular and Optical Physics. 49(8), Article 084006. https://doi.org/10.1088/0953-4075/49/8/084006