Hampton University MARC Program - Personnel

Dr. Paul L. Gueye Dr. Paul L. Gueye Department Chair/Assistant Professor, Physics Location:Olin Engineering Building102E Phone:757-727-5542

Educational Background:
B.S. in Physics and Chemistry, University of Cheikh Anta Diop (Senegal), 1987
M.S. in Physics and Chemistry, University of Cheikh Anta Diop (Senegal), 1990
Ph.D. in Nuclear Physics, University of Clermont-Ferrand (France), 1994

Research Interests:

Experimental Nuclear Physics, Accelerator Physics, Medical Physics, Space Science, Geant4 Simulation

The knowledge of the properties of the nuclear matter has been largely done via electron scattering. In most experiments, higher order effects originating from the exchange of multiple photons have been neglected in the electron-nucleus/electron-nucleon scattering amplitude: the reaction mechanism is believed to be dominated by the exchange of one hard virtual photon that carries all the energy transferred to the target nucleus (or nucleon). Interference terms between one- and multiple-photon exchange provides odd powers in αZ that will have opposite signs for electrons and positrons. This feature enables access to a powerful clean tool to measure their contribution to the differential cross section. Polarized electrons and positrons are also required to enable access to particular physics observables. Since obtaining my PhD, I have been very interested in the development of such positron beams and its applications in nuclear/high-energy physics at Jefferson Lab. This capability will open new opportunities for this laboratory and future facilities. Such program is currently under way (PEPPo Experiment) and expected to start in the Fall 2011. My group is responsible for many key components of its implementation including both accelerator physics and nuclear physic aspects.

Accelerators are used in many areas and applications range from medical (x-ray machines, cancer based electron, photon and proton therapies, manufacturing of radio-isotopes) to high-energy physics, including food sanitization, radiation biology, and earth-based space science studies. One of the old thermo-ionic guns of the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab is in the process of being transferred to Hampton University to primarily serve as an educational tool in accelerator physics. This gun is a DC source that can generate electrons with kinetic energies up to 100 keV and has a total estimated value of about $200k. In the mid- to long-term goal, this gun will be expanded to a Low Energy LInear Accelerator (LELIA) capable of accelerating electrons up to a maximum of 500 keV within the next 2 years. LELIA will be the first such accelerator at a Historically Black College University (HCBU) and is one of the primary effort of my group.

I am also involved in medical physics research in primarily three areas: absolute dose measurements (to provide the construction of detectors that have the capability of 2D and 3D dose measurements within 100 μm), in-vivo dose distribution measurements (to provide novel devices that have capabilities of measuring the dose distribution effectively delivered within a patient during radiation based treatments) and cancer cells study (looking at the energy dependence of cancer cells as well as on the physics responsible for cancer cell death and the use of polarized beams in cancer treatments).

The Geant4 (Geometry AnTracking, version 4) Monte Carlo simulation toolkit is was developed to simulate the interaction of particles with matter. Its applicability ranges from the eV to TeV energy regime, and is found in many applications in physics high-energy, nuclear, astrophysics, optical sciences, material sciences, accelerators, medical …). Geant4 is used in most of the research conducted under my group. I am also responsible for this tool in our Physics Department and at Jefferson Lab.

Selected Publications

  1. A. Mantero et al.PIXE simulation in Geant4, X-Ray Spectrometry, 40 (2011).
  2. S. Incerti et al., Comparison of Geant4 very low energy cross section models with experimental data in water, Med. Phys. Jour., 37, 4692 (2010).
  3. P. GuèyeEnergy distribution mapping of beta radioactive sources, Nuclear Instrumentation and Methods in Physics Research, A578, 442-449, (2007).
  4. F. Dohrman et al.Quasifree Lambda, ∑0, and ∑- electroproduction from 1,2H, 3,4He, and Carbon, Phys. Rev. C, vol 76, 054004 (2007).
  5. M. Mazouz et al.Deeply Virtual Compton Scattering off the neutron, Phys. Rev. Lett., vol 99, 242501 (2007).
  6. M. Epps, P. Guèye and R. Kazimi, Low Energy Experimental Elastic Cross Sections for L. Yuan et al.:Hypernuclear Spectroscopy using the (e,e'K+) Reaction, Phys. Rev., C73, 044607 (2006).
  7. R. Williams and P. GuèyeQuark Molecular Model of the S=0 Strange Pentaquark (usbar)-(uds) Baryon Spectrumnucl-th/0308058 (2003).
  8. R. M. Mohring et al.Separation of the longitudinal and transverse cross-section in the p(e,e'K+)Λ and p(e,e'K+)Σ0 reactions, Phys. Rev. C67, 055205 (2003).
  9. K. Garrow et al.Nuclear transparency from quasi-elastic A(e,e'p) reactions up to Q2 = 8.1 (GeV/c)2, Phys. Rev., C66, 044613 (2002).
  10. P. Guèye et al.Correction to the one-photon approximation in the O+→2+ transition of 12C, Phys. Rev.,C63, 051303(R) (2001).
  11. J. Reinhold et al.Electroproduction of kaons and light hypernuclei, Nucl. Phys., A684 (2001).
  12. I. Niculescu et al.Evidence for valence like quark hadron duality, Phys. Rev. Lett., 85, 1182-1185 (2000).
  13. P. Guèye et al.Monte Carlo simulation for the p(e,e'K+)vec{Λ} reaction, Fizika, B9 (2000).
  14. D. Abbott et al.Measurement of tensor polarization in elastic electron deuteron scattering at large momentum transfer, Phys. Rev. Lett., 84, 5053-5057 (2000).
  15. L. Teodorescu, P. Guèye et al.Λ Polarization in associated K+Λ electro-production, Nucl. Phys., A658(1999).
  16. T. Angelescu, A. Mihul, L. Teodorescu, O.K. Baker, P. Guèye, G. Niculescu, I. Niculescu: K+ electroproduction in exclusive ē + p → K+ + Λ reaction, Rom. Rep. Phys., 51, 551-560 (1999).
  17. P. Guèye et al.Coulomb distortion measurements by comparing electron and positron quasi-elastic scattering off 12C and 208Pb, Phys. Rev., C60 (1999).
  18. K. Assamagan, P. Guèye et al.Electron Beam Characteristics of a Laser-Driven Plasma Wakefield Accelerator, Nucl. Inst. and Meth., A438 (1999).
  19. C. Furget et al.Tensor polarization measurement in elastic electron deuteron scattering at large momentum transfer, Acta Phys. Polon., B29 (1998).
  20. P. Guèye et al.Dispersive effects by a comparison of electron and positron scattering from 12C, Phys. Rev., C57, vol. 5 (1998).
  21. J. Smilowitz, S. Avery, P. Gueye and G. Sandison, Report on the American Association of Medical Physics undergraduate fellowship programs, J. Appl. Clinic. Med. Phys., 14, 4159 (2013).
  22. V. N. Ivanchenkoet al., Combination of electromagnetic Physics processes for microdosimetry in liquid water with the Geant4 Monte Carlo simulation toolkit, Nucl. Instrum. and Meth., B 273, 95-97 (2012).

Have Questions?

Please contact Dr. Cecile Andraos-Selim, HU MARC Program Director, Associate Professor of Biology, Department of Biological Sciences; DU117; 757-727-5015; cecile.andraos-selim@hamptonu.edu

The MARC Program is Funded by NIH/NIGMS Grant #1T34GM105550-01A1