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STORAGE RING CROSS SECTION MEASUREMENTS FOR ELECTRON IMPACT SINGLE AND DOUBLE IONIZATION OF Fe13+ AND SINGLE IONIZATION OF Fe16+ AND Fe17+.
- Source :
- Astrophysical Journal; 4/10/2013, Vol. 767 Issue 1, p1-7, 7p
- Publication Year :
- 2013
-
Abstract
- We report measurements of electron impact ionization for Fe<superscript>13+</superscript>, Fe<superscript>16+</superscript>, and Fe<superscript>17+</superscript> over collision energies from below threshold to above 3000 eV. The ions were recirculated using an ion storage ring. Data were collected after a sufficiently long time that essentially all the ions had relaxed radiatively to their ground state. For single ionization of Fe<superscript>13+</superscript>, we find that previous single pass experiments are more than 40% larger than our results. Compared to our work, the theoretical cross section recommended by Arnaud & Raymond is more than 30% larger, while that of Dere is about 20% greater. Much of the discrepancy with Dere is due to the theory overestimating the contribution of excitation-autoionization via n = 2 excitations. Double ionization of Fe<superscript>13+</superscript> is dominated by direct ionization of an inner shell electron accompanied by autoionization of a second electron. Our results for single ionization of Fe<superscript>16+</superscript> and Fe<superscript>17+</superscript> agree with theoretical calculations to within the experimental uncertainties. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 0004637X
- Volume :
- 767
- Issue :
- 1
- Database :
- Complementary Index
- Journal :
- Astrophysical Journal
- Publication Type :
- Academic Journal
- Accession number :
- 90114329
- Full Text :
- https://doi.org/10.1088/0004-637X/767/1/47