Dr. Frank Strieder

Associate Professor

Department of Physics
South Dakota School of Mines and Technology
501 E. Saint Joseph St., SD 57701

Office: EEP 219
E-mail: frank.strieder@sdsmt.edu

Research Interest

Nuclear Astrophysics is a thriving and exciting field of research at the interface of nuclear physics, astrophysics, and particle physics. The field is driven by three major topics: quiescent nuclear burning in stars, explosive nuclear burning, and nuclear processes at extreme densities. These topics are interlinked scientifically but require the use of fundamentally different instrumentation.

My major research interest is associated with the first question, the nucleosynthesis in stars and its impact on the production of heavy elements. In particular, my group seeks to study the strength of stellar neutron sources that drive the s-process, one of the two dominant sources for the production of heavy elements. The most critical reactions are 13C(α,n)16O and 22Ne(α,n)25Mg but other (α,n) reactions may also play a role depending on the stellar environment. The study of these reactions at stellar energies has been a major goal by the community, both in Europe and the US. However, the large cosmic ray induced neutron background has been prohibitive for advancing these measurements into the stellar energy range and the present reaction rates rely on theoretical extrapolations that carry high uncertainties. There has been no facility where these measurements can be pursued in a background neutron free environment. An accelerator laboratory, located deep underground would offer unique conditions for measuring these reactions at low energies as demonstrated by the success of the LUNA facility at Gran Sasso, Italy. Luna showed for the case of hydrogen burning reactions that many of these kinds of extrapolations have been seriously wrong.

Over the past years the CASPAR (Compact Accelerator System for Performing Astrophysical Research) laboratory has been constructed at the Sanford Underground Research Facility (SURF). The facility was built and equipped with support through SURF, the University of Notre Dame, and the South Dakota School of Mines & Technology. CASPAR operates a 1MV, high intensity, fully refurbished Van de Graaff accelerator that can provide α beam intensities of several hundred micro-Ampere. The CASPAR laboratory will allow US scientists direct access to an underground accelerator and is a first step to a broader range facility as envisioned by the long range plan document. Successful implementation of a science program at CASPAR will offer a competitive opportunity for the US nuclear astrophysics community to maintain leadership in the field.

The ultimate goal for the next years would be to pave the road for a study of the two most important reactions for the understanding of stellar evolution, the reactions 12C(α,γ)16O and 12C+12C, in an underground accelerator laboratory. This would lead to unprecedented lower energy limits and, thus, extrapolations with higher accuracy than currently available as well as a significant improvement of the input parameters for stellar models.

Classroom Teaching

PHYS 792: Nuclear Physics of Stars (Spring 2016)
PHYS 361: Optics (Fall 2016)
PHYS 765: Advanced Nuclear Physics (Spring 2017)
PHYS 211: University Physics I (Fall 2017)