Low Energy Experimental Nuclear Physics

Experimental low energy nuclear physics research within the INPP spans a variety of topics, including nuclear astrophysics, nuclear structure, nuclear energy, homeland security, and materials science. Carl Brune , Gang Chen , Steve Grimes , David Ingram , Tom Massey , and Alexander Voinov pursue a diverse set of research programs, frequently collaborating on joint projects.

Several aspects of nuclear astrophysics are investigated through the low-energy nuclear experimental program within the INPP. Broadly speaking, this work aims to explain the origin of the elements in the universe and the behavior or extremely dense, low-temperature matter. Each of these investigations involves an array of experimental and theoretical low-energy nuclear physics techniques. Examples of current and recently completed projects are:

• Direct and indirect measurements of ¹² C(α,γ) for red giant star cores (Brune)
• Scattering cross section measurements for high-precision determinations of solar neutrino yields (Brune)
• Direct cross section measurements of (α,n) cross sections for core collapse supernova nucleosynthesis (Brune, Massey)
• Indirect measurements of (p,γ) and (α,p) cross sections for type-I x-ray bursts (Brune, Grimes, Massey, Voinov)
• Level density and γ-strength function measurements for reaction ratses of astrophysical interest (Voinov, Grimes)

Reaction mechanism studies within the INPP have impacted reaction rate calculations ncecessary for nuclear astrophysics, nuclear structure, and nuclear energy. A variety of techniques, including charged-particle, neutron, and γ spectroscopy, are used to determine nuclear level densities, γ-strength functions, and optical model potentials. Examples of current and recently completed projects are:

• Level density and γ-strength function measurements for isotopes of Ni, Zn, Co, and Zr (Voinov, Grimes)
• Explorations of the impact of spin-cutoff and spin-distributions in Hauser-Feshbach calculations (Grimes, Voinov)
• Inclusion of deformation and isospin effects into Hauser-Feshbach calculations (Grimes, Massey, Voinov)

Detector development and testing are a key function of the low energy nuclear physics program at Ohio Unviersity's Edwards Accelerator Laboratory. Specifically, the lab has focused on improving neutron detection techniques for various applications. This work exploits the neutron detection expertiese, as well as the quasi-monoenergetic neutron beams available at the lab. Examples of current and recently completed projects are:

• Characterization of the HABANERO neutron long-counter for nuclear astrophysics measurements (Massey, Brune)
• Characterization of the VANDLE scinitillator array for nuclear structure and astrophysics studies (Massey)
• Re-evaluation of ¹⁰ B(n,Z) cross section data presently employed in neutron detection simulations (Massey)

Several studies within the INPP low-energy nuclear physics program are in the category of applied nuclear physics . This includes efforts focused on improving the udnerstanding of internal confinement fusion, as well as improved data for modeling and neutron transpot materials. Examples of current and recently completed projects are:

• Cross section measurements for and with internal confinement fusion plasmas (Brune)
• Study of transport of MeV neutrons in iron for nuclear reactor models (Brune, Massey, Grimes)
• Characterization of diamond-like carbon films (Ingram)
• Refinement of ¹¹ B(d,n) and ¹¹ B(d,nγ) data to improve detection of fissionable materials (Ingram, Massey)

A unique capability of the Edwards Accelerator Lab is the ability to perform condensed matter physics studies by taking advantage of the W.M. Keck Thin Films Analysis Facility, which is on a dedicated beamline on the accelerator. The Keck Facility enables the creation and characterization of thin films within an ultra-high vacuum environment. Examples of current and recently completed projects are:

• Band-gap characterziation of GaN semiconductors for various Ga:N ratios (Ingram)
• Characterization of disordered materials using ion beams (Chen)

• Edwards Accelerator Lab (on the OU campus)
• Los Alamos National Lab
• National Ignition Facility
• NSCL/FRIB at MSU
• Oslo Cyclotron Laboratory
• TRIUMF

Associated faculty: Brune , Chen , Grimes , Ingram , Massey , Voinov