In a recent Physical Review C paper, scientists from Hope College, Central Michigan University, the University of Notre Dame, the Institute for Nuclear Research (ATOMKI) in Hungary, and FRIB present the first measurement of the proton capture on krypton-82. Together with the experimental results, the team used theoretical calculations to allow for an improved description of important astrophysical reactions in explosive stellar environments. Physical Review C also highlighted the paper as an Editor’s Suggestion.

Although most nuclei heavier than iron are likely produced by the slow and the rapid neutron-capture processes, a number of medium-mass, proton-rich nuclei are thought to be produced via photo-disintegration (the so-called γ-process). Unfortunately, most reactions involved are extremely challenging to measure experimentally. Therefore, one needs to rely on detailed statistical model calculations that are constrained by experimental input.

In this paper, the authors studied the capture of protons on krypton-82, producing the unstable rubidium-83 nucleus. A krypton-82 beam interacted with a hydrogen gas target, and a large-volume gamma-ray detector measured the produced gamma rays. The results put important constraints on statistical model calculations, allowing improved tests of the γ-process in hot stellar environments.

The authors of the paper include Artemis Tsantiri, graduate assistant at FRIB; Alicia Palmisano-Kyle, former graduate research assistant at FRIB (and current postdoc at the University of Tennessee-Knoxville); Artemis Spyrou, professor of physics at FRIB and in the Michigan State University (MSU) Department of Physics and Astronomy; Hannah Berg, graduate assistant at FRIB; Alexander Dombos, graduate assistant at FRIB; Erin Good, research associate at FRIB; Caley Harris, graduate assistant at FRIB; Sean Liddick, associate professor of chemistry at FRIB and in MSU’s Department of Chemistry, and FRIB associate director for experimental science; Stephanie Lyons, research associate at FRIB; Gerard Owens-Fryar, graduate assistant at FRIB; Jorge Pereira, instrument scientist at FRIB; Andrea Richard, adjunct research associate at FRIB; Mallory Smith, staff scientist at FRIB; Remco Zegers, professor of physics at FRIB and in MSU’s Department of Physics and Astronomy.

This material is based upon work supported by the U.S. National Science Foundation, the U.S. Department of Energy (DOE) National Nuclear Security Administration, and the DOE Office of Science Office of Nuclear Physics.

Michigan State University (MSU) operates the Facility for Rare Isotope Beams (FRIB) as a user facility for the U.S. Department of Energy Office of Science (DOE-SC), supporting the mission of the DOE-SC Office of Nuclear Physics. User facility operation is supported by the DOE-SC Office of Nuclear Physics as one of 28 DOE-SC user facilities.

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