Los Alamos National Laboratory

Los Alamos National Laboratory

Delivering science and technology to protect our nation and promote world stability


Learn from the brightest minds and experts in the field of nondestructive assay technologies in support of nuclear nonproliferation.


Matthew Carpenter

Matt Carpenter works on advanced detector development for nuclear safeguards in the Nuclear Engineering and Nonproliferation division (NEN-1). He received his Ph.D. in applied physics from UC Davis in 2015 with a background in synchrotron x-ray spectroscopy and superconducting detector development for materials science. He transitioned to LANL after a stint in private industry working on superconducting sensors and electronics, and current projects include nanoscale x-ray spectral imaging as well as advanced gamma ray detectors for safeguards.

Daniela Henzlova


Daniela Henzlova has been working in the Safeguards Science and Technology Group at the Los Alamos National Laboratory since 2009. Her primary focus is on neutron detection technologies for nuclear safeguards applications and associated advanced data acquisition concepts (development of list mode data collection and analysis for safeguards). She has extensive experience with the design, fabrication, fielding and evaluation of measurement systems for both, nuclear material accounting and international safeguards objectives for the fuel cycle facilities in Japan.  She currently leads several projects for the Japanese facilities’ accounting systems for facilities including Rokkasho Reprocessing Plant, J-MOX fuel fabrication plant (planned) and Tokai Reprocessing Plant. She is actively engaged in LANL training program, including the International Atomic Energy Agency courses and training of Japanese partners. Prior to joining LANL, Daniela was pursuing a fundamental nuclear research career and worked at National Superconducting Cyclotron Laboratory in Michigan as well as at Heavy Ion Research Institute in Darmstadt, Germany. Daniela is originally from Czech Republic.



Brian Jennings


Brian Jennings is an engineer with the International Threat Reduction group, NEN-3, at Los Alamos National Laboratory (LANL). Brian received his B.S. in nuclear engineering and mechanical engineering from Rensselaer Polytechnic Institute in 2011 and his M.S. in nuclear engineering from the University of New Mexico in 2019. He joined LANL in 2016, primarily in support of the science and engineering team (SET) for the Office of Nuclear Smuggling Detection and Deterrence (NSDD). In support of the NSDD SET, Brian has focused on low-resolution gamma radiation detection systems, evaluating system performance, troubleshooting abnormal behavior, and developing modeling and simulation tools to understand system performance in use-case specific configurations.


Pete Karpius

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Pete is a gamma-ray spectroscopist with the Advanced Nuclear Technology Group (NEN-2) at Los Alamos National Laboratory. He is a peer-qualified analyst with the DOE Radiological Triage program as well as for deployable nuclear emergency response positions. Pete participates in software development, gamma-ray laboratory measurements, predictive radiation modeling, and provides instruction to DOE, DOD, DHS, and DOJ personnel in support of the nuclear emergency response mission. Furthermore, Pete continues to be a gamma-ray analysis instructor for the assay of plutonium and uranium items in several foreign and domestic nuclear safeguards schools as well as the International Atomic Energy Agency inspector courses at LANL. Prior to joining LANL in January 2006, he completed his doctoral studies at the University of New Hampshire with research conducted in electron scattering from light nuclei.


Katrina Koehler


Katrina Koehler is a scientist with the Safeguards Science and Technology group, NEN-1. She received her B.S. in math and physics from Houghton College in 2011 and her M.A. and Ph.D. in physics from Western Michigan University in 2014 and 2019 respectively. She has been working with NEN-1 since 2011, primarily on R&D projects in the fields of neutron multiplicity, low temperature detectors for alpha, x-ray, and gamma spectroscopy, and Hartree-Fock style atomic physics calculations. Katrina has been an instructor for the NDA neutron course and INSEP.



Paul Mendoza


Paul Mendoza studied nuclear engineering at Texas A&M at the Center for Nuclear Security Science and Policy Institute (NSSPI). His PhD was granted May 2018 in the area of nuclear forensics and spent fuel reprocessing. His undergraduate degree was in engineering physics at Biola University. For the last 2 years he has worked in the Non-proliferation division at Los Alamos National Laboratory and has taught in several courses at the TA-66 school house. Paul teaches almost exclusively neutron NDA and thoroughly enjoys the subject matter and the art behind conveying technical information through pictures and intuition based examples. He is known to pull out old textbooks for illustrations and will do his best to try and instill intuition for neutron NDA.



David Mercer


David J. Mercer graduated in 1993 with a Ph.D. in Physics from the University of Colorado, and is a member of the Physical Chemistry and Spectroscopy group at LANL. He has been active in developing gamma-ray methods for nuclear safeguards and emergency response since 1996, and is the skillset manager for the US Department of Energy Radiological Triage Program. 


Carlos Rael


Carlos Rael studied electronics technology and has worked in radiation detection and safeguards measurements for 27 years. Carlos was part of the LANL team that set up the infrastructure and made measurements for the very first shipment to the Waste Isolation Pilot Plant (WIPP). During his time in working on waste management, he was introduced to the NEN-1, Nuclear Safeguards Science and Technology, group. First as a client to specify equipment of WIPP measurements, then as a student the Safeguards School and finally as employee. He contributed to the design of safeguards instruments and technology, tested and calibrated both neutron and gamma instruments, has led or participated in many field installations of LANL designed safeguards instruments and continue to be an instructor for both domestic and safeguards schools.


Margie Root

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Margaret Root completed her B.S. in Nuclear Engineering at the University of New Mexico in 2011. She has been working at Los Alamos National Laboratory since 2012, beginning as a summer intern, then working as a post-bac, and finally supporting the Nuclear Engineering and Nonproliferation Division’s Safeguards Science and Technology Group (NEN-1) in research on the Uranium Neutron Coincidence Collar for her Master’s research. She completed her Master’s degree in Nuclear Science and Engineering at the Massachusetts Institute of Technology in September 2015. She is now an R&D Engineer in NEN-1. She has taught and designed many courses both at LANL and internationally, including the International Atomic Energy Agency course,  the Nuclear Material Control and Accountancy course, and neutron courses in support of the China Center of Excellence in Nuclear Security. Her current work includes research on fresh and spent nuclear fuel verification techniques, teaching/designing neutron NDA courses, and working as an operations engineer for the Chemical Camera on the Curiosity Rover.


Sarah Sarnoski


Sarah Sarnoski is an R&D Engineer on the Enabling Technologies team in the Safeguards, Science, and Technology Group. Sarah supports a variety of projects at the lab with a focus on international safeguards, and she teaches both gamma and neutron NDA courses. Prior to joining LANL, Sarah was an NNSA Graduate Fellow in the Office International Nuclear Safeguards and conducted her PhD research at Pacific Northwest National Laboratory. Sarah has a PhD and MS in nuclear engineering from Pennsylvania State University and a BS in nuclear engineering from University of Florida.


Jacob Stinnett

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Jacob earned a PhD in Nuclear, Plasma, and Radiological Engineering at the University of Illinois at Urbana-Champaign. Jacob’s undergraduate work was in physics and math at the University of Oklahoma. The focus of his grad school work was on nuclear security applications of gamma-ray spectroscopy, particularly in automated nuclide identification algorithms for low-resolution handheld detectors. At LANL, Jacob has expanded his work and knowledge to include many safeguards applications, such as isotopic analysis with medium-resolution detectors, UF6 cylinder chronometry, calorimetry, and more.

Alexis Trahan

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Dr. Alexis Trahan is a scientist with the Safeguards Science and Technology group, NEN-1. She received her B.S. in nuclear engineering from UC Berkeley in 2011 and her M.S. and Ph.D. in the same field from the University of Michigan in 2012 and 2016 respectively. She joined Los Alamos National Laboratory as a Graduate Research Assistant in the summer of 2012 and carried out her thesis research with NEN-1 until she was converted to a technical staff member in 2015. Alexis works on development of detection instrumentation and analytical methods with an emphasis on neutron detection for international nuclear safeguards and nonproliferation. She is currently developing and testing technologies for used power reactor and research reactor fuel characterization. In 2014, Dr. Trahan was awarded the University of Michigan Towner Prize for Outstanding Ph.D. Research for her thesis on development of a spent fuel nondestructive assay instrument for IAEA safeguards. During her graduate studies, she was a Nuclear Forensics Graduate Fellow and won 1st place in the DOE Innovations in Fuel Cycle Research competition. Alexis is an adjunct faculty member at the University of Texas at Austin and holds leadership positions in the American Nuclear Society. Alexis has been the organizer for the International Nuclear Safeguards and Engagement Program (INSEP) course, which took place in 2018 at LANL, and has taught several courses while in NEN-1 for the Safeguard and Security Technology Training Program.

Duc Vo

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Duc Vo’s primary area of research is in the development of new gamma ray detection and analysis techniques/systems to be used in nuclear safeguards. He is the developer of the latest FRAM isotopic analysis code, FRAM version 5.2. This code is a powerful NDA tool to measure the uranium and plutonium isotopic compositions. His current activities include exploring new applications for the FRAM code and further improvement of the FRAM isotopic analysis code, especially the capability to analyze uranium and plutonium spectra acquired with a LaBr3 or large CZT detector. In the past, he has worked extensively with manufacturers of gamma ray detectors and electronics to improve the performances of gamma ray detector systems. Duc received a BS in Physics from University of Northern Iowa and a PhD in Nuclear Physics from Iowa State University.


Robert Weinmann-Smith

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Robert Weinmann-Smith has a PhD in Nuclear Engineering in simulating radiation detectors for safeguards. He joined NEN-1 in 2014. He previously worked on improving simulations of neutron detectors and currently works on designing and calibrating facility specific detection equipment for the assay of spent nuclear fuel. Robert has instructed in more than 10 NDA courses, and creates courses specific to the equipment he designs.