Nuclear physics

News and Updates

A twist and a spin: harnessing two quantum properties transforms a neutron beam into a powerful probe of material structure

October 29, 2019

By cleverly manipulating two properties of a neutron beam, NIST scientists and their collaborators have created a powerful probe of materials that have complex

Six people stand in front of a tan building, cutting a blue ribbon

NIST Unveils New Laboratory Building for Improved National Radiation Measurements

September 24, 2019

GAITHERSBURG, Md. — The U.S. Department of Commerce’s National Institute of Standards and Technology (NIST) held a ribbon-cutting ceremony yesterday to unveil a

JILA’s Novel Atomic Clock Design Offers ‘Tweezer’ Control

September 12, 2019

JILA physicists have demonstrated a novel atomic clock design that combines near-continuous operation with strong signals and high stability, features not

Projects and Programs

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

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

Precision Measurement of the Neutron-He3 Incoherent Scattering Length

The Neutron Interferometer and Optics Facility performed a precision measurement of the n-3He incoherent scattering length using a polarized 3He gas target for

Neutron Detector Replacement Program

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

Fundamental Experiments with a Precision Neutron Polarimeter

The Neutron Spin Rotation (NSR) collaboration has developed a neutron spin polarimeter that has allowed the precise measurement of spin rotations at a level of

Publications

Ra-224 activity, half-life, and 241 keV gamma ray absolute emission intensity: a NIST-NPL bilateral comparison

December 31, 2020

Author(s)

Denis E. Bergeron, Sean Collins, Leticia Pibida, Jeffrey T. Cessna, Ryan P. Fitzgerald, Brian E. Zimmerman, Peter Ivanov, John Keightley, Elisa Napoli

The national metrology institutes for the United Kingdom and the United States have compared activity standards for 224Ra, an -particle emitter of interest as

Non-fuel Antineutrino Contributions in the High Flux Isotope Reactor

May 14, 2020

Author(s)

PROSPECT COLLABORATION, Jerome J. LaRosa, Hans P. Mumm, Svetlana Nour, Mark A. Tyra, Denis E. Bergeron

Reactor neutrino experiments have seen major improvements in precision in recent years. With the experimental uncertainties starting to surpass those from

ERRATUM: UPDATE OF NIST HALF-LIFE RESULTS CORRECTED FOR IONIZATION CHAMBER SOURCE-HOLDER INSTABILITY

May 1, 2020

Author(s)

Ryan P. Fitzgerald, Michael P. Unterweger

Accurate Integral Counting Using Multi-channel Analyzers

May 1, 2020

Author(s)

Ryan P. Fitzgerald, Lynne E. King

Many techniques in radionuclide metrology rely on accurate measurement of the total count rate, that is integral counting, from a detector. In modern

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