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National Superconducting
Cyclotron Laboratory

Remco Zegers
Remco Zegers
Experimental Nuclear Physics
PhD, Mathematics and Natural Sciences, State University of Groningen, 1999
Joined NSCL in February 2003
Phone 517-908-7473
Office 3131
zegers at nscl.msu.edu

Remco Zegers

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What makes a star explode and eject its material into space to create planets like earth? What is the mass of the neutrino? And what forces govern the properties of nuclei? These are some of the questions we are trying to address in a variety of experiments performed at the NSCL. These questions are very diverse, but we use a common tool to investigate all: charge-exchange reactions.

In a nuclear reaction, a projectile nucleus collides with a target nucleus. In a charge-exchange reaction, they exchange a proton for a neutron. The strong nuclear force governs these reactions. But the underlying physics tells us about reactions caused by the weak nuclear force. These include electron capture and beta decay, which are important in astrophysical phenomena. We are especially interested in supernovae and processes that create elements in the universe. Another category of processes that we study are those that involve neutrinos. Such processes also have astrophysical applications. In addition, they help us better understand how these strange particles interact with matter.

To do the best experiments and interpret the data, we collaborate with theorists and astrophysicists. Still, we perform many of the calculations ourselves. Student thus gain a deep understanding of the theory, experiments, and astrophysical applications.

The experiments we perform require that the beam velocity exceeds 35% of the speed of light. This ensures that the charge-exchange reaction is simple and easy to model. FRIB/NSCL is perfectly suited for providing such isotope beams. We also run experiments at other facilities that have specific capabilities that complement our in-house program. For example, we regularly perform experiments in Japan.

Students play an important role in the development of novel experimental tools. We primarily focus on experiments aimed at studying properties of unstable isotopes. We have built a neutron detector specifically suited for charge-exchange reactions with unstable isotopes. We use magnetic spectrometers, often in combination with detectors for photons or neutrons. We also develop new types of reactions that reveal nuclear properties otherwise hard to study. And we often collaborate with other groups who have developed unique detectors that enhance our research. I am also heavily involved with the development of a new spectrometer for FRIB: the High Rigidity Spectrometer.

Our group is active in the Joint Institute for Nuclear Astrophysics-Center for the Evolution of the Elements (JINA-CEE). We lead the development of a library for electron-capture rates that astrophysicists use. The use of charge-exchange reactions for the above science goals is unique in the U.S. But since the applications of our results are so diverse, we have connections to many researchers in and outside of the U.S. The student in the charge-exchange group are key to all these efforts!


LENDA

The Low-Energy Neutron Detector Array (LENDA) is used for (p,n) charge-exchange experiments in inverse kinematics. It has been upgraded to use a digital data acquisition system and is presently being upgraded to include more scintillator bars.Save

Selected Publications

Impact of electron-captures on nuclei near N=50 on core-collapse supernovae, R. Titus et al., J. Phys. G 45, 014004 (2017)

Observation of the Isovector Giant Monopole Resonance via the Si-28 (Be-10, B-10* [1.74 MeV]) Reaction at 100 AMeV – M. Scott et al., Phys. Rev. Lett. 118, 172501 (2017).

The Sensitivity of Core-Collapse Supernovae to nuclear Electron Capture – C. Sullivan et al., The Astrophysical Journal, 816, 44 (2016).

β+ Gamow-Teller Transition Strengths from 46Ti and Stellar Electron-Capture Rates. S. Noji et al. Phys. Rev. Lett. 112, 252501 (2014)

Probing configuration mixing in 12Be with Gamow-Teller transition strengths, R. Meharchand et. al., Phys. Rev. Lett. 108, 122501 (2012).

Gamow-Teller Transition Strengths from 56Ni M. Sasano et. al., Phys. Rev. Lett. 107, 202501 (2011), see also K. Langanke, Physics 4, 91 (2011).