Leadership, Governance
View Leadership Team Photo Org Chart (pdf)
portrait | landscape

Thomas Mason
Laboratory Director
Thomas (Thom) Mason is the President and CEO of Triad National Security, LLC (Triad) and serves as the Director of Los Alamos National Laboratory. Most recently he was the Senior Vice President for Global Laboratory Operations at Battelle where he had responsibility for governance and strategy across the six National Laboratories that Battelle manages or co-manages. For the past 30 years, he has been involved in the design and construction of scientific instrumentation and facilities and the application of nuclear, computing, and materials sciences to solve important challenges in energy and national security.
View Leadership Team Photo Org Chart (pdf) portrait | landscape

Robert Webster
Deputy Director Weapons
Robert (Bob) Webster serves as the Deputy Director Weapons at Los Alamos National Laboratory (LANL). In this role, Bob has direct line management responsibility for planning, coordinating, and integrating the Weapons Program, particularly for the directorates of Weapons Engineering, Weapons Design and Weapons Production. Bob is a 29-year veteran of the Weapons Program at LANL and a recognized leader in Stockpile Stewardship.

John Sarrao
Deputy Director Science, Technology, and Engineering
John Sarrao serves as the Deputy Director Science, Technology, and Engineering at Los Alamos National Laboratory (LANL), leading the Laboratory’s STE capabilities in supporting the Laboratory’s national security mission.

Kelly Beierschmitt
Deputy Director Operations
Kelly Beierschmitt serves as the Deputy Director Operations of Los Alamos National Laboratory (LANL). Kelly has worked more than 30 years in the service of critical DOE missions. Most recently, he was the Deputy Laboratory Director for Science and Technology and Chief Research Officer for Idaho National Laboratory (INL) where he had responsibility for setting the scientific and engineering agenda and overseeing the research, development, demonstration and deployment of the critical missions for the Laboratory

Frances Chadwick
Staff Director
Frances Chadwick serves as the Laboratory Director’s Staff Director. In this role, she supports the Director and Deputy Directors and manage the various offices that report into the Director’s office. Frances has worked at Los Alamos National Laboratory (LANL) since 1996 in various positions in Finance and Infrastructure.

Charlie Nakhleh
Associate Laboratory Director, Weapons Physics
Charles W. Nakhleh is the Associate Laboratory Director for Weapons Physics (ALDX) at Los Alamos National Laboratory. In this role, he has line responsibility for the nuclear weapons designers and simulation code architects at the Laboratory, as well as program responsibility for the NA-11 weapons science, computing, and technology maturation portfolio.

James Owen
Associate Laboratory Director, Weapons Engineering
James Owen serves as the Associate Laboratory Director, Weapons Engineering for Los Alamos National Laboratory. James has worked in LANL’s Nuclear Weapons Program for more than 25 years and is a recognized leader across the Nuclear Security Enterprise (NSE). He has demonstrated technical and program leadership abilities in successfully executing some of NNSA and DoD’s most significant and challenging nuclear weapon programs, including the B61 Alt 357, W80 LEP, W76-1/Mk4A LEP, B61-12 LEP, W88 Alt 370 and W88 Alt 940.

Mark Anthony
Associate Laboratory Director, Plutonium Infrastructure
Mark Anthony serves as Associate Laboratory Director for Plutonium Infrastructure (ALDPI) at Los Alamos National Laboratory. In this role, he oversees execution of the 30 pits-per-year mission through modernization of the TA-55 infrastructure and capabilities.

John Benner
Associate Laboratory Director, Weapons Production
John Benner is the associate Laboratory director for Weapons Production (ALDWP) at Los Alamos National Laboratory. In this role, he has responsibility for the production and evaluation of plutonium pits, nuclear weapon detonators, and other nonnuclear components. ALDWP also oversees plutonium processing and disposition, manufacturing of power supplies for NASA deep space missions, surveillance, nuclear materials management, and waste operations.

Nancy Jo Nicholas
Associate Laboratory Director, Global Security
Nancy Jo Nicholas serves as Associate Laboratory Director, Global Security for Los Alamos National Laboratory. In this role, she leads the execution of programs in the areas of Defense Nuclear Nonproliferation, Nuclear Counter-Proliferation and Counter-terrorism, and Strategic Partnership Programs, as well as oversee the Field Intelligence Element. Nancy Jo has worked for LANL since 1990.

Antoinette Taylor
Associate Laboratory Director, Physical Sciences
Antoinette (Toni) Taylor serves as the Associate Laboratory Director, Physical Sciences for Los Alamos National Laboratory. Toni’s background is in nanophotonics and ultrafast dynamics of quantum and nanoscale materials.

Patrick Fitch
Associate Laboratory Director, Chemical, Earth and Life Sciences
Patrick (Pat) Fitch serves as the Associate Laboratory Director, Chemical, Earth and Life Sciences for Los Alamos National Laboratory. Since March 2020, Pat also leads the LANL Special Office for COVID-19 R&D (SOC-19). Most recently, Pat was the President of the Battelle National Biodefense Institute, LLC (BNBI) and founding Director of the National Biodefense Analysis and Countermeasures Center (NBACC), a Department of Homeland Security Federally Funded Research and Development Center.

Irene Qualters
Associate Laboratory Director, Simulation and Computation
Irene Qualters serves as the Associate Laboratory Director for Simulation and Computation. ALDSC advances modeling, simulation, and computation essential to LANL’s science and security missions. Through multidisciplinary co-design engaging theory, experiment, and computation, ALDSC explores, develops and deploys world-leading computational methods, analysis, and technologies. Irene previously served as a Senior Science Advisor in the Computing and Information Science and Engineering (CISE) Directorate of the National Science Foundation (NSF) and has over 30 years serving in executive leadership positions in research and development in the technology sector, including 20 years at Cray Research, where she was a pioneer in the development of high performance parallel processing technologies to accelerate scientific discovery.

Michael Hazen
Associate Laboratory Director, Environment, Safety, Health & Quality and Safeguards and Security (ESHQSS)
Michael Hazen serves as the Associate Laboratory Director, Environment, Safety, Health & Quality and Safeguards & Security (ESHQSS) for Los Alamos National Laboratory. Michael served as Vice President of Infrastructure Operations and Chief Security Officer at Sandia National Laboratories where he had responsibility for Facilities, Safeguards and Security, Emergency Management and Environment, and Safety and Health.

LeAnne Stribley
Associate Laboratory Director, Business Management
LeAnne Stribley serves as the Associate Laboratory Director, Business Management for Los Alamos National Laboratory. She has more than 35 years of multi-industry experience building and leading the finance, accounting, procurement, IT and administration functions of public, private and nonprofit entities.

Bret Simpkins
Associate Laboratory Director, Facilities and Operations
Bret Simpkins serves as the Associate Laboratory Director for Facilities and Operations at Los Alamos National Laboratory. Bret was the Director of Facilities and Operations for Pacific Northwest National Laboratory (PNNL) where he was responsible for campus-wide facility strategic planning, projects and engineering, operations and maintenance, nuclear operations, and real estate management functions.