Past Team Members

Todd Evans
Todd Evans

Todd Evans, Postdoctoral scholar: Dr. Evans implemented sensitivity analysis, uncertainty quantification, and parameter estimation using data assimilation in the massively-parallel neutron transport code DENOVO.  He applied DENOVO to analyze neutron counting measurements of subcritical assemblies of weapons-grade plutonium, and he demonstrated that the current evaluated value of the induced-fission mean neutron multiplicity (nu-bar) for 239Pu is high by more than 2 standard deviations.  Dr. Evens now works for the Texas Advanced Computing Center (TACC) at UT Austin.  His work is currently being advanced by RADIANS Ph.D. students Sean O’Brien and Alex Clark.

 

Dr. Tony Nettleton
Tony Nettleton

Tony Nettleton, Postdoctoral scholar: Dr. Nettleton developed a method to eliminate the effects of chemical and mechanical fractionation on gamma spectroscopic measurements of nuclear fallout.  His work enabled forensic analysis of nuclear fallout using gamma spectroscopic measurements with field-deployable instruments.  Dr. Nettleton now works for the Los Alamos National Laboratory (LANL) Offsite Source Recovery Project (OSRP).  His research is currently being advanced by RADIANS M.S. student Gabe Lucero.

 

Dr. Jun Li
Jun Li

Jun Li, Research associate (University of North Carolina): Dr. Li implemented computational methods to analyze the accuracy, precision, and stability of inverse analyses to estimate special nuclear material (SNM) properties from gamma spectroscopic and neutron counting measurements.  He now works for AREVA North America in Maryland.

 

Dave Anderson
Dave Anderson

Dave Anderson: Dave has a B.S. in Nuclear Engineering, an M.S. in Computer Science, and he worked for General Dynamics Electric Boat for more than two decades conducting radiation shielding and design calculations for the US and UK nuclear submarine programs.  With RADIANS, Dave developed a platform for the inverse analysis of gamma spectroscopic measurements of special nuclear material (SNM), and he applied the tools he developed to identify degeneracies in inverse solutions for SNM mass, surface area, and isotopic composition.  Dave is now an instructor in the NCSU NE department, where he teaches NE201: Introduction to Nuclear Engineering and NE419: Introduction to Nuclear Energy.

 

Matthew Avetian
Matthew Avetian

Matthew Avetian, M.S. student (graduated 2015): Matthew developed methods to accelerate Monte Carlo simulations of gammas produced by neutron capture.  The code he developed enabled the efficient computational prediction of gamma spectroscopic measurements  of materials irradiated by neutrons.  Matthew is now a test engineer for the Newport News shipyard, where nuclear submarines are constructed.

 

Noah Bullock
Noah Bullock

Noah Bullock, M.S. student (graduated 2014): Noah developed nonlinear regression methods to correct pulse pileup in cerium bromide (CeBr3 – a new inorganic scintillator) gamma spectroscopy measurements using digital data acquisition (DAQ) and signal processing (DSP).  The tools he developed enabled medium-resolution gamma spectroscopy measurements at extremely high count rates typical in active interrogation of Special Nuclear Material (SNM).  Noah is now a contractor to Customs and Border Patrol (CBP), where he trains CBP agents to detect underground tunnels into the US using ground-penetrating radar (GPR).  Noah also trains US and international explosive ordinance disposal (EOD) teams in radiation detection as an independent consultant.

 

Mark Delgado
Mark Delgado

Mark Delgado, B.S. student (graduated 2014): Mark developed an Android-based smartphone system for radiation measurements using Geiger-Mueller counters.  Mark won research grants from the National Collegiate Inventors and Innovators Alliance (NCIIA) and the NCSU Office of Undergraduate Research, and he founded Koyr Engineering, Inc. to commercialize his radiation detection system.

 

Alex Okowita
Alex Okowita

Alex Okowita, B.S. student (graduated 2014): Alex conducted independent research to develop nonlinear regression methods to infer neutron multiplication from subcritical neutron multiplicity measurements of special nuclear material (SNM).  He analyzed benchmark measurements of weapons-grade plutonium, and presented his findings to the Institute of Nuclear Materials Management (INMM) during their 2012 annual meeting.  Alex recently completed his M.S. in Nuclear Engineering with Prof. Jason Hayward at University of Tennessee, Knoxville.

 

Chelsea Ratzlaff
Chelsea Ratzlaff

Chelsea Ratzlaff, M.S. student (graduated 2014): Chelsea developed Monte Carlo computational simulations of the response function of ORNL’s HPGe-based coded-aperture gamma camera.  Chelsea’s work will enable quantitative identification of gamma sources found in high-resolution gamma imaging measurements.

 

Zach Bailey
Zach Bailey

Zach Bailey, M.S. student (graduated 2013): Zach developed several techniques for neutron-gamma discrimination for the liquid organic scintillation material EJ-309 using digital data acquisition (DAQ) and signal processing (DSP).  Zach’s research produced new, improved methods for time-correlated measurements of fast (fission-spectrum) neutrons.  Zach presented his research to the Institute of Nuclear Materials Management (INMM) during their 2013 annual meeting, and he won a J. D. Williams student poster award for his research.

 

Christine Latten
Christine Latten

Christine Latten, M.N.E. Student (graduated 2012): Christine developed a computational framework for neutron transport model calibration using data assimilation.  Her work enabled nuclear data evaluation using critical experiments.