Nuclear physics

News and Updates

Incoming radiation deposits energy into the TKID circuit.

NIST Study Probes the Damaging Effects of Radiation on Qubits

November 19, 2024

Qubits, the fundamental unit of quantum information, form the building blocks of quantum computers. Because qubits are not limited to the two states, “0” and “1

View from near ceiling shows NCNR guide hall filled with big pieces of scientific equipment, including several long cylindrical "guides" running toward the far end of the room.

New Report Highlights Economic Value of Neutron Science to U.S. Industry

September 5, 2024

Research using neutron beams provides an economic return far larger than the cost of building and operating neutron facilities, according to an economic impact

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

Projects and Programs

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

Completed

While inner-bremsstrahlung has been measured in nuclear beta decay and electron capture decays, it has only recently been observed in free neutron beta decay. In 2006, we reported the first observation of this radiative decay mode in the journal Nature. The experiment was completed at the NG-6

Applied: Methods in Neutron Detection and Spectroscopy

Completed

Energetic neutrons (> 1 MeV) play a variety of important roles from dosimetry to the fundamental sciences. Fast neutrons can be an often under-appreciated but significant biological dose from accelerators and nuclear facilities, serve as a way of detecting nuclear materials, and can often yield

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

Completed

The stars and galaxies that make up our universe can only form if, during the initial moments after the Big Bang, there existed a slight dominance of matter over antimatter. It has been understood for some time that such an imbalance can only be explained if three conditions are met; a departure

Security (Archive): Neutron Detector Replacement Program

Completed

This course of action has included an intense sequence of tests of alternative technologies performed at the Los Alamos National Laboratory and the Nevada National Security Site. NIST has been integral to all phases of these testing programs, including evaluation of submitted detectors, design and

Publications

Pre-conceptual Design Activities of the NIST Neutron Source: Preliminary Thermal-hydraulics Assessments

February 10, 2025

Author(s)

Abdullah Weiss, Anil Gurgen, Evan Bures, Joy Shen

The NIST Neutron Source (NNS) is the proposed reactor for ensuring continued future availability of neutrons for the United States' scientific needs. The NNS

NIST Neutron Source Pre-Conceptual Design

February 10, 2025

Author(s)

David Diamond, Abdullah Weiss, Osman Celikten, Jeremy Cook, Dagistan Sahin, Hubert King, Anil Gurgen, Joy Shen

A pre-conceptual design has been completed for a NIST Neutron Source (NNS). It would replace the existing facility at the NIST Center for Neutron Research (NCNR

A bilateral comparison of 227Th activity standards between NPL and NIST

February 3, 2025

Author(s)

Andrew Fenwick, Denis Bergeron, Brittany Broder, Emma Bendall, Jeffrey Cessna, Sean Collins, Leticia Pibida, Natasha Ramirez, Elisa Napoli

The National Physical Laboratory (United Kingdom) and the National Institute of Standards and Technology (United States) each determined the massic activity and

Activity measurements and calibrations for 225Ac in radioactive equilibrium with its progeny

December 9, 2024

Author(s)

Denis Bergeron, Gulakhshan Hamad, Brittany Broder, Jeffrey Cessna, Adam Pearce, Jerome LaRosa, Leticia Pibida, Brian E. Zimmerman

The massic activity of 225Ac in 0.1 mol/L HCl was measured by multiple primary methods over four consistent measurement campaigns. Results from the triple-to

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