Alan A. Chen

SHARC: Silicon Highly-segmented Array for Reactions and Coulex used in conjunction with the TIGRESS γ-ray spectrometer

The combination of γ-ray spectroscopy and charged-particle spectroscopy is a powerful tool for the study of nuclear reactions with beams of nuclei far from stability. This paper presents a new silicon detector array, SHARC, the Silicon Highly-segmented Array for Reactions and Coulex. The array is used at the radioactive-ion-beam facility at TRIUMF (Canada), in conjunction with the TIGRESS γ-ray spectrometer, and is built from custom Si-strip detectors utilising a fully digital readout. SHARC has more than 50% efficiency, approximately 1000-strip segmentation, angular resolutions of Δθ ≈ 1.3 deg and Δ ≈ 3.5 deg, 25–30 keV energy resolution, and thresholds of 200 keV for up to 25 MeV particles. SHARC is now complete, and the experimental program in nuclear astrophysics and nuclear structure has commenced.

30S Beam Development and X‐ray Bursts

Over the past three years, we have worked on developing a well‐characterized 30S radioactive beam to be used in a future experiment aiming to directly measure to extrapolate the 30S(α,p) stellar reaction rate within the Gamow window of Type I X‐ray bursts. The importance of the 30S(α,p) reaction to X‐ray bursts is discussed. Given the astrophysical motivation, the successful results of and challenges involved in the production of a low‐energy 30S beam are detailed. Finally, an overview of our future plans regarding this on‐going project are presented.Over the past three years, we have worked on developing a well‐characterized 30S radioactive beam to be used in a future experiment aiming to directly measure to extrapolate the 30S(α,p) stellar reaction rate within the Gamow window of Type I X‐ray bursts. The importance of the 30S(α,p) reaction to X‐ray bursts is discussed. Given the astrophysical motivation, the successful results of and challenges involved in the production of a low‐energy 30S beam are detailed. Finally, an overview of our future plans regarding this on‐going project are presented.

Measurements with DRAGON on resonances in the 21Na(p, γ)22Mg reaction with a radioactive ion beam

Abstract In the modelling of nucleosynthesis in nova explosions, temperature and density are important parameters to describe the hydrodynamics. Those parameters are not easy to observe, but specific gamma-ray emitters produced in the explosion provide constrains on the models, such as 22 Na, produced via 21 Na ( p , γ ) 22 Mg ( β + ) 22 Na . The new DRAGON recoil separator facility, designed and built to measure directly the rates of radiative proton and alpha capture reactions, important for nuclear astrophysics, is now operational. Experiments have been conducted on the 21 Na(p , γ) 22 Mg reaction using a radioactive 21 Na beam incident onto a windowless hydrogen gas target. Yield measurements have been performed detecting the prompt gamma and the reaction recoils at E cm ≈ 821 keV and 204 keV.

Measurement of the Beta Decay of 26P to Determine Classical Nova 26Al Production in the Milky Way

1 Department of Physics and Astronomy, Michigan State University, East Lansing MI 48824, United States 2 National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing MI 48824, United States 3 Department of Physics, University of Washington, Seattle, Washington 98195, USA 4 Department of Physics, Colorado School of Mines, Golden CO 80401, United States 5 Departament Física i Enginyeria Nuclear (UPC) and Institut dEstudis Espacials de Catalunya (IEEC), E-08034 Barcelona, Spain 6 Department of Chemistry, Michigan State University, East Lansing, MI 48824, United States 7 Physics Department, Kalamazoo College, Kalamazoo, Michigan 49006, USA 8 Department of Physics and Astronomy, McMaster University, Hamilton ON L8S 4M1, Canada 9 Department of Physics and Wright Nuclear Structure Laboratory, Yale University, New Haven, Connecticut 06520, USA 10 Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, MI 48824, United States 11 Oak Ridge National Laboratory, Oak Ridge TN 37831, United States 12 Department of Electrical Engineering, Michigan State University, East Lansing 13 Geology and Physics Department, University of Southern Indiana, Evansville IN 47712, United States

25Al+p Elastic Scattering with CRIB

J. Pearson, A. A. Chen, S. Kubono, H. Yamaguchi, J. J. He, L. H. Khiem, A. Saito, G. Amadio, H. Fujikawa, M. Niikura, Y. Wakabayashi, T. Teranishi, S. Nishimura, Y. Togano, A. Odahara, f J. Y. Moon, Y. K. Kwon,, S. Cherubini, R. Pizzone, M. La Cognata, Department of Physics and Astronomy, McMaster University, Canada Centre for Nuclear Study, University of Tokyo, Japan Department of Physics, Kyushu University, Japan RIKEN, Japan Rikkyo University, Tokyo, Japan f Nishinippon Institute of Technology, Japan Department of Physics, Chung-Ang University, Korea University of Catania, Italy

Study of astrophysically important resonant states in

Department of Physics, Chung-Ang University, Republic of K orea aCenter for Nuclear Study, Graduate School of Science, Unive rsity of Tokyo, Japan bDepartment of Physics, Tohoku University, Japan cInstitute of Physics and Electronics, Vietnam dKEK (The High Energy Accelerator Organization), Japan eDepartment of Physics and Astronomy, McMaster University, Canada fDepartment of Physics, Yamagata University, Japan

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Kiana Setoodehnia∗†a, Alan A. Chena, Jason A. Clarkbc, Catherine M. Deibelbc, David Kahla, Peter D. Parkerb, and Christopher Wredebd aDepartment of Physics & Astronomy, McMaster University, Hamilton, ON L8S 4M1, Canada bWright Nuclear Structure Laboratory, Yale University, New Haven, CT 06520, USA cPhysics Division, Argonne National Laboratory, Argonne, IL 60439, USA dDepartment of Physics, University of Washington, Seattle, WA 98195-1560, USA