Nuclear physics

News and Updates

Imaging the Elusive Skyrmion

September 25, 2023

Scientists at the National Institute of Standards and Technology (NIST) with colleagues elsewhere have employed neutron imaging and a reconstruction algorithm

New NIST Licensing Opportunity Teems with Potential Applications

July 5, 2023

Max Planck, one of the Twentieth Century’s most eminent physicists, observed, "An experiment is a question that science poses to Nature, and a measurement is

Research on the Rocks: Combining Neutrons and X-Ray Imaging, NIST Scientists Study Meteorites to Explore the Mystery of How Earth Acquired Its Water

November 3, 2022

Each year, hundreds of meteorites — rocky bodies left over from the formation of the solar system — bombard Earth, delivering minerals, metals and water to our

Projects and Programs

Fundamental Physics: Precision Measurement of the Branching Ratio and Energy Spectrum of Radiative Neutron Decay

Completed

Neutron beta-decay is typically considered as a three-body process, but it is always accompanied by inner-bremsstrahlung soft photons, n → e − + p + ν e + γ

Applied: Methods in Neutron Detection and Spectroscopy

Ongoing

We continue to work improving techniques in fast neutron detection using segmented spectrometers based on the principle of capture-gating. Our approach employs

Fundamental Physics: Search for Time Reversal Violation in Polarized Neutron Decay (emiT)

Completed

The "emiT" experiment searched for time-reversal symmetry violation term in neutron beta decay. It did so by measuring electron-proton coincidence events from

Security (Archive): Neutron Detector Replacement Program

Completed

The Department of Homeland Security/Domestic Nuclear Detection Office (DHS/DNDO) is pursuing a course to transform 3He alternative technologies into integrated

Publications

Activity standard and calibrations for 227Th with ingrowing progeny

April 20, 2024

Author(s)

Denis E. Bergeron, Jeffrey T. Cessna, Brittany Broder, Leticia Pibida, Ryan P. Fitzgerald, Morgan DiGiorgio, Elisa Napoli, Brian E. Zimmerman

Thorium-227 was separated from its progeny and standardized for activity by the triple-to-double coincidence ratio (TDCR) method of liquid scintillation

Ambient humidity, the overlooked influencer of radioactivity measurements

November 27, 2023

Author(s)

Stefaan Pomme, Michael P. Unterweger, Ryan P. Fitzgerald, Denis E. Bergeron, Leticia Pibida, International Collaboration

When verifying the validity of the exponential-decay law through 128 precise decay rate measurement series at various nuclear laboratories, minor violations

The 2023 Status Update on the LEU Conversion of the NBSR

November 15, 2023

Author(s)

Abdullah Weiss, Osman Celikten, Dagistan Sahin, Anil Gurgen, Thomas Newton

Liquid scintillation efficiencies, gamma-ray emission intensities, and half-life for Gd-153

November 9, 2023

Author(s)

Denis E. Bergeron, Jeffrey T. Cessna, Ryan P. Fitzgerald, Gulakhshan Hamad, Lizbeth Laureano-Perez, Leticia Pibida, Brian E. Zimmerman

Gadolinium-153 was standardized for activity by live-timed anticoincidence counting and an ampoule was submitted to the international reference system (SIR)

Tools and Instruments

Positron Annihilation Lifetime Spectrometer

Positron annihilation lifetime spectroscopy uses positrons to probe material defects/voids/free volume at the sub-nm scale. The general working principle is

Material Analysis Using Neutron Depth Profiling

Light elements such as helium, lithium, boron, and nitrogen are essential constituents in materials that enable energy technologies; lithium ion batteries