1999 Progress Report
(PDF, 300KB)
2000 Progress Report
(PDF, 200KB)
Dissertation
(PDF, 1.3MB)
Dissertation with signatures
(PDF, 4.1MB)
Electron Microbeam, Extended Abstract
[2003 ANS Winter Meeting] (PDF,
90KB)
Curriculum Vita
[updated 10/2006] (DOC,
50KB)
I earned my Ph.D. from the Nuclear Chemistry program here at Texas A&M University, located in the Cyclotron Institute, where we have our own K=500 Superconducting Cyclotron for use with experiments by program members as well as outside users. I started the program in the Spring of 1990, coming in with a 1987 B.S. in Organic Chemistry and some work experience at O.I. Corporation installing and repairing environmental chemistry equipment all over the U.S., which needless to say didn't prepare me well for the nuclear field. My graduate work consisted of the research described a few paragraphs below and work on related projects, as well as teaching undergraduate chemistry labs - everything from inorganic to physical to analytical to nuclear. Eventually, I ended up graduating in the Fall of 1999.
While I was ABD for my PhD, I took a research associate position working for the TAMU Nuclear Engineering Department as a Research Associate. My responsibilities included operation, tuning, and maintenance of a National Electrostatics 2UDH Tandem Van de Graaff accelerator and its Alphatross Ion Source. I developed beam control systems for accurate microbeam delivery to cellular targets in vitro. I was also involved in a number of other projects and duties, including operating our Norelco X-Ray machine for irradiating our (usually biological) samples, operation and maintenance of our homegrown 100 kV electron accelerator, as well as desiging and updating some of the computer control aspects of these machines. I also developed and maintained our LAN and oversaw our electronics tech and a number of student workers. I also taught NUEN 201, "Modern Physics for Nuclear Engineers", which covered probability and statistics, relativity, atomic physics, and quantum mechanics, and a smattering of related material.
Until recently, I worked in the Material Research Program of the National Center for Preservation Technology and Training (NCPTT) as a Joint Faculty Researcher. My duties were divided into half-time faculty for the Department of Chemistry and Physics at Northwestern State University and half time at NCPTT. At NCPTT, I was primarily working on a comparative study evaluating the relative performance of various stone consolidant treatments on calcareous stone used in monuments and buildings. At NSU, I taught chemistry and physics lectures and labs.
Currently, I am a Research Staff Member at the Institute for Defense Analyses, a non-profit government-established think-tank (FFRDC). I work in the Operational Evaluation Division, supporting DOT&E oversight of DoD acquisition programs.
My PhD research dealt with the dynamical properties of nuclear fission, concentrating on the actual time scale of the fission process. While this has been investigated quite a bit, the answers are still unclear. There are primarily two ways one can estimate the time scale for fission, either through investigating pre- and post-scission neutron multiplicities or by examining the gamma ray spectrum of the fissioning system, concentrating on the region where the E1 giant dipole resonance (GDR) de-excitation occurs. Both of these methods have been investigated a number of times for a number of different systems, and they both involve comparison with various statistical model codes, such as GEMINI or CASCADE.
Until that research, these two methods have always been investigated separately, and have always given fission times differing by as much as 1-2 orders of magnitude between the two. My experiments involve gathering data sufficient to accomplish both of these analyses within the same experiment. I then analyze them using similar methods, thus getting the most comparable numbers possible. The experiments were calibrated and the data painstakingly analyzed to look for only appropriate events that correspond to fission after compound nucleus formation. With 80 GB of data on 4 systems (16O + 208Pb, 16O + 176Yb, 4He + 209Bi, 4He + 188Os) to sift through, you can expect it to take some appreciable time. After that, statistical model calculations were utilized to eventually give us our numbers for the time scale of nuclear fission. The effects of different fission mass asymmetries on the time scale was also investigated, as well as whether or not any shape information on the compound system before fission can be extracted from the GDR gamma ray spectral shape.
