The first direct measurement of 17O(α,γ) 21Ne and its impact upon s-process abundances

M. Taggart, U. Hager, A. M. Laird, C. Ruiz, D. Hutcheon, D. Ottewell, J. Fallis, L. Erikson, M. Bentley, J. R. Brown, L. Buchmann, A. A. Chen, J. Chen, K. A. Chipps, J. D'Auria, B. Davids, C. Davis, C. A. Diget, S. P. Fox, B. FultonN. Galinski, U. Greife, F. Herwig, R. Hirschi, D. Howell, L. Martin, D. Mountford, A. Murphy, M. Pignatari, S. Reeve, G. Ruprecht, S. Sjue, L. Veloce

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An experimental campaign to perform the first accurate measurement of the 17O(α,γ)21Ne reaction rate was carried out during May and November 2009 at the DRAGON recoil separator in the TRIUMF laboratory, Vancouver, Canada. The goals were to differentiate between two previous conflicting theoretical predictions, and to establish the (α,γ)/(α,n) reaction rate ratio. Two distinct energy regions were scanned: a higher region, Ecm ∼ 1.5 MeV, where the recoil cone was sufficiently confined and the cross section sufficiently large so that a statistically significant yield could be achieved, and a lower region, E cm ∼ 0.7 MeV, chosen to approach the astrophysical energies and reduce errors from extrapolation. The experiment, performed in inverse kinematics, used the highest intensity beam ever delivered to DRAGON, 1×1012 pps of 17O incident on a 4He gas target. An array of 30 Bismuth Germanate (BGO) detectors [1] was used in conjunction with two microchannel plates (MCP) [2] for a local time-of-flight measurement, and ion chamber for coincident event detection.

Original languageEnglish
JournalProceedings of Science
Publication statusPublished - 1 Dec 2010

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