First Measurement of a Weak <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>r</mml:mi></mml:math>-Process Reaction on a Radioactive Nucleus

This Letter reports on the first cross-section measurements for the ^{94}Sr(α,n)^{97}Zr and ^{86}Kr(α,n)^{89}Sr reactions. In particular, our measurement of ^{94}Sr(α,n)^{97}Zr is the first weak r-process reaction cross section obtained using a radioactive ion beam. This experiment was enabled by the use of novel solid helium targets, comprised of silicon thin films with high helium incorporation obtained via a sputtering technique. Yield measurements were performed at center-of-mass energies of 10.4 and 9.0 MeV for the ^{86}Kr(α,n)^{89}Sr reaction, and 9.9 MeV for ^{94}Sr(α,n)^{97}Zr, extending into the respective Gamow energy windows for a temperature of 5 GK. Reactions were uniquely identified by prompt γ rays detected in coincidence with heavy ions selected by a recoil mass spectrometer. The obtained cross sections are smaller than predicted for both reactions. In the case of ^{94}Sr(α,n)^{97}Zr, the reaction rate found here is lowered by an order of magnitude at temperatures below 5 GK, which is expected to impact the predicted abundance of ruthenium, a signature weak r-process element.

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Publication Details

Journal
Physical Review Letters
Published
2025-03-17
DOI
https://doi.org/10.1103/physrevlett.134.112701
Citations
5
Primary Topic
Nuclear physics research studies
Type
article
Field-Weighted Citation Impact
9.35

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article

First Measurement of a Weak <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>r</mml:mi></mml:math>-Process Reaction on a Radioactive Nucleus

A. Psaltis, A. M. Laird, A. A. Avaa, Christian Aa. Diget et al.
5 citations
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Nuclear physics research studies
9.35
article

First Measurement of a Weak <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>r</mml:mi></mml:math>-Process Reaction on a Radioactive Nucleus

A. Psaltis, A. M. Laird, A. A. Avaa, Christian Aa. Diget, M. S. Martin, K. Hudson, S. Chakraborty, G. Hackman, M. Williams, Thierry Sauvage, V. Karayonchev, M. Satrazani, F. Montes, Daniel Rhodes, J. O’Neill, C. Angus, G. Lotay, B. Marlow, I. Dillmann, J. Williams, C. J. Griffin, A. N. Andreyev, J. R. Murias, Dirk Hufschmidt, A. Fernández, M. C. Jiménez de Haro, J. Henderson, C. Paxman, A. Lennarz, D. Yates, B. Davids, C. E. Svensson, Louis K. Wagner, G. Bartram, E. Raleigh-Smith, H. Asch, D. T. Doherty, Jong Hwi Jeong, J. S. Rojo, A. Grimes, Kihong Pak, Diana Tam, S. Molló, L. Pedro-Botet, A. Katrusiak, K. Directo, E. Geerlof, C. Shenton
article en
5 citations

Abstract

This Letter reports on the first cross-section measurements for the ^{94}Sr(α,n)^{97}Zr and ^{86}Kr(α,n)^{89}Sr reactions. In particular, our measurement of ^{94}Sr(α,n)^{97}Zr is the first weak r-process reaction cross section obtained using a radioactive ion beam. This experiment was enabled by the use of novel solid helium targets, comprised of silicon thin films with high helium incorporation obtained via a sputtering technique. Yield measurements were performed at center-of-mass energies of 10.4 and 9.0 MeV for the ^{86}Kr(α,n)^{89}Sr reaction, and 9.9 MeV for ^{94}Sr(α,n)^{97}Zr, extending into the respective Gamow energy windows for a temperature of 5 GK. Reactions were uniquely identified by prompt γ rays detected in coincidence with heavy ions selected by a recoil mass spectrometer. The obtained cross sections are smaller than predicted for both reactions. In the case of ^{94}Sr(α,n)^{97}Zr, the reaction rate found here is lowered by an order of magnitude at temperatures below 5 GK, which is expected to impact the predicted abundance of ruthenium, a signature weak r-process element.

Physical Review LettersVol. 134(11)
TRIUMF (CA), University of British Columbia (CA), University of Liverpool (GB), Simon Fraser University (CA), University of Surrey (GB), Technische Universität Darmstadt (DE), Université Bourgogne Franche-Comté (FR), Conditions Extrêmes et Matériaux Haute Température et Irradiation (FR), Facility for Rare Isotope Beams, Hanyang University (KR), University of York (GB), Universidad de Sevilla (ES), University of Guelph (CA), Michigan State University (US), Universitat Politècnica de Catalunya (ES), McMaster University (CA)
Bundesministerium für Bildung und Forschung, Natural Sciences and Engineering Research Council of Canada, National Research Council Canada, Science and Technology Facilities Council, European Regional Development Fund, Agencia Estatal de Investigación
Affordable and clean energy
Openalex Percentile: Top 3%
Nuclear physics research studies
9.35
DOIOpen Access PDFOpenAlex
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