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.
Howell, C. R., et al. “Neutron-deuteron elastic scattering and breakup reactions below 20 MeV.” Nuclear Inst. and Methods in Physics Research, B, vol. 56–57, no. PART 1, May 1991, pp. 459–63. Scopus, doi:10.1016/0168-583X(91)96070-2. Full Text
Tornow, W., et al. “The low-energy neutron-deuteron analyzing power and the 3P0,1,2 interactions of nucleon-nucleon potentials.” Physics Letters B, vol. 257, no. 3–4, Mar. 1991, pp. 273–77. Scopus, doi:10.1016/0370-2693(91)91892-Y. Full Text
WEISEL, G. J., et al. “NEUTRON-PROTON ANALYZING POWER DATA AT 7.6, 12.0, 14.1, 16.0, 18.5 MEV.” Journal De Physique, vol. 51, no. 22, EDP SCIENCES S A, Nov. 1990, pp. C6515–18.
Pedroni, R. S., et al. “Analyzing power measurements for elastic scattering of 17 MeV neutrons from 120Sn.” Physical Review. C, Nuclear Physics, vol. 41, no. 6, June 1990, pp. 2929–30. Epmc, doi:10.1103/physrevc.41.2929. Full Text
Howell, C. R., et al. “Techniques for vector analyzing power measurements of the 2H(n, np)n breakup reaction at low energies.” Nuclear Inst. and Methods in Physics Research, A, vol. 290, no. 2–3, May 1990, pp. 424–36. Scopus, doi:10.1016/0168-9002(90)90560-S. Full Text
Tornow, W., et al. “Few-body physics investigated through polarized neutron experiments in A ≤ 3 systems at TUNL.” Nuclear Inst. and Methods in Physics Research, B, vol. 40–41, no. PART 1, Apr. 1989, pp. 470–73. Scopus, doi:10.1016/0168-583X(89)91023-9. Full Text
Guss, P. P., et al. “Optical model description of the neutron interaction with 116Sn and 120Sn over a wide energy range.” Physical Review. C, Nuclear Physics, vol. 39, no. 2, Feb. 1989, pp. 405–14. Epmc, doi:10.1103/physrevc.39.405. Full Text
Tornow, W., et al. “Analysing power for 12C(n,n0,1)12C and evaluation of n-12C scattering at 18.2 MeV.” Journal of Physics G: Nuclear Physics, vol. 14, no. 1, Dec. 1988, pp. 49–64. Scopus, doi:10.1088/0305-4616/14/1/009. Full Text
Pedroni, R. S., et al. “Energy dependence of the deformed optical potential for neutron scattering from 54,56Fe and 58,60Ni up to 80 MeV.” Physical Review. C, Nuclear Physics, vol. 38, no. 5, Nov. 1988, pp. 2052–62. Epmc, doi:10.1103/physrevc.38.2052. Full Text
Howell, C. R., et al. “Rigorous calculations and measurements of Ay( theta ) for n+d elastic-scattering and breakup processes.” Physical Review Letters, vol. 61, no. 14, Oct. 1988, pp. 1565–68. Epmc, doi:10.1103/physrevlett.61.1565. Full Text