Calvin R. Howell
Professor of Physics
Professor Howell’s research is in the area of experimental nuclear physics with emphasis on the quantum chromodynamics (QCD) description of low-energy nuclear phenomena, including structure properties of nucleons and nuclei and reaction dynamics in few-nucleon systems. The macroscopic properties of nucleon structure and the residual strong nuclear force between neutrons and protons in nuclei emerge from QCD at distances where the color interactions between quarks and gluons are strong. However, the details of the mechanisms that generate the strong nuclear force are not well understood. Effective field theories (EFT) and Lattice QCD calculations provide theoretical frames that connect low-energy nuclear phenomena to QCD. Professor Howell and collaborators are conducting experiments on few-nucleon systems that test predictions of ab-initio theory calculations for the purpose of providing insight about the QCD descriptions of low-energy nucleon interactions and structure. His current projects include measurements of the electromagnetic and spin-dependent structure properties of nucleons via Compton scattering on the proton and few-nucleon systems and studies of two- and three-nucleon interactions using few-nucleon reactions induced by photons and neutrons. In the coming years, a focus will be on investigating the neutron-neutron interaction in reactions and inside nuclei. In addition, his work includes applications of nuclear physics to national nuclear security, medical isotope production, and plant biology. Most of his research is carried out at the High Intensity Gamma-ray Source and the tandem laboratory at TUNL.
Tornow, W., et al. “Proposal for the Simultaneous Measurement of the Neutron-Neutron and Neutron-Proton Quasi-Free Scattering Cross Section via the Neutron-Deuteron Breakup Reaction at E n = 19 MeV.” Few Body Systems, 2012, pp. 1–4.
Arnold, C. W., et al. “Characterization of an INVS model IV neutron counter for high precision (γ,n) cross-section measurements.” Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, vol. 647, no. 1, Aug. 2011, pp. 55–62. Scopus, doi:10.1016/j.nima.2011.01.177. Full Text
Mueller, J. M., et al. “Asymmetry dependence of nucleon correlations in spherical nuclei extracted from a dispersive-optical-model analysis.” Physical Review C Nuclear Physics, vol. 83, no. 6, June 2011. Scopus, doi:10.1103/PhysRevC.83.064605. Full Text
Raut, R., et al. “Cross-section measurements of neutron-induced reactions on GaAs using monoenergetic beams from 7.5 to 15 MeV.” Physical Review C Nuclear Physics, vol. 83, no. 4, Apr. 2011. Scopus, doi:10.1103/PhysRevC.83.044621. Full Text
Kwan, E., et al. “Discrete deexcitations in U235 below 3 MeV from nuclear resonance fluorescence.” Physical Review C Nuclear Physics, vol. 83, no. 4, Apr. 2011. Scopus, doi:10.1103/PhysRevC.83.041601. Full Text
Adekola, A. S., et al. “Discovery of low-lying E1 and M1 strengths in Th232.” Physical Review C Nuclear Physics, vol. 83, no. 3, Mar. 2011. Scopus, doi:10.1103/PhysRevC.83.034615. Full Text
Raut, R., et al. “Cross section measurements of neutron induced reactions on GaAs using monoenergetic beams from 7.5 to 15 MeV.” Journal of Physics: Conference Series, vol. 312, no. SECTION 6, Jan. 2011. Scopus, doi:10.1088/1742-6596/312/6/062008. Full Text
Weisenberger, A. G., et al. “Development of PhytoPET: A plant imaging PET system.” Ieee Nuclear Science Symposium Conference Record, Jan. 2011, pp. 275–78. Scopus, doi:10.1109/NSSMIC.2011.6154496. Full Text
Weisenberger, A. G., et al. “Compact beta particle/positron imager for plant biology.” Ieee Nuclear Science Symposium Conference Record, Dec. 2010, pp. 1752–54. Scopus, doi:10.1109/NSSMIC.2010.5874074. Full Text