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NIST Center for Neutron Research

NG7 NIOF

NG7 NIOF Header

Instrument Purpose

To provide the world’s most precise platform for measuring the coherent wave properties of the neutron, enabling definitive tests of quantum mechanics, and the determination of fundamental physical constants.

The NCNR Advantage

  • Unparalleled Phase Stability: NIOF is housed in a World Class “room-within-a-room" configuration, featuring a 40,000 kg vibration isolation slab and active thermal control stable to within ± 0.005 K. This allows for phase measurements with relative uncertainties < 0.00001 - the gold standard for neutron interferometry.
  • The "Perfect Crystal" Laboratory: The facility specializes in the use of monolithic silicon perfect crystals to split and recombine neutron waves. This creates a macroscopic quantum superposition that can extend over several centimeters, making it a unique "quantum sandbox" for researchers.
  • A Primary Metrology Standard: NIOF is the definitive source for the world's most accurate coherent neutron scattering lengths, which are critical for the calibration and interpretation of all other neutron scattering techniques (SANS, Reflectometry, etc.) and benchmarking nucleon-nucleon interaction models.
NIOF schematic - full-size
Figure 4: Experiments that require the absolute best phase stability are performed inside a large Hutch. The Hutch is decoupled from the local environment (especially from vibrations) to preserve the neutron interferometer’s stability over relatively long measurement times (60 seconds).
Credit: NIST

Research Domains

  • Quantum Foundations: Exploring entanglement, contextuality, and the quantum coherence using the neutron’s three degrees of freedom (path, spin, and energy).
  • Structured Waves: Exploiting the neutron’s wave nature to encode, complex structure on the neutron wave function including Orbital Angular Momentum and Airy States for topological material research and noise rejection.
  • Nuclear Metrology: Precise measurement of neutron-nucleus scattering lengths for fundamental constants database.
  • Fundamental Physics: The sensitivity of neutron interferometry enables the search for particular Dark Energy candidates and tests of the equivalence principle.

What You Can Measure

  • Phase Shifts: Detecting the tiniest changes in the neutron's wave function caused by magnetic fields, mechanical motion, material density, and quantum mechanical phenomenon.
  • Coherent Scattering Lengths (bc): Measuring the absolute interaction strength between neutrons and matter with unprecedented accuracy.
  • Beam Coherence: Analyzing the longitudinal and transverse spatial coherence of the cold neutron beam.

Technical Specifications

ParameterSpecification
Source TypeCold Neutrons (NG-7 Guide)
MonochromatorHigh-quality Pyrolytic Graphite (PG 002)
Wavelength (λ)0.32 nm to 0.46 nm (Selectable)
Wavelength Spread (Δλ/λ)~ 0.01 (Inside Interferometer)
InterferometerMonolithic Silicon Perfect Crystal (several geometries)
Phase Stability0.1 deg per Day
Thermal Stability± 0.005 K

Specialized Sample Environments

  • Active Vibration Damping: The experiment is mounted on a massive granite table supported by feedback-controlled, pneumatic isolators to eliminate seismic noise.
  • Acoustic & Thermal Enclosure: A specialized multi-layered box protects the interferometer from air currents, acoustic vibrations, and temperature fluctuations.
  • Precision Phase Shifters: Rotating quartz or aluminum paddles used to induce controlled, sub-nanometer path length changes.

Expertise & Support

  • The NIOF Team: Led by Dr. Michael Huber, the team consists of a collaboration with university partners that include U. of Waterloo, Institute of Quantum Computing, University at Buffalo, NC State, Indiana University, Tulane University, University of Nagoya and others.
  • Quantum Information Consulting: Expert assistance in designing "quantum state tomography" experiments and entanglement verification.
  • Software & Data Analysis:
    • NIOF-a: Our specialized, NIST-developed data acquisition and analysis system ensures efficient, high-impact science.
    • Metrology Integration: Direct pipeline for integrating interferometric results into the NIST scattering length database.
  • Collaboration Strategy: Due to the extreme sensitivity of the setups, most NIOF experiments are collaborative efforts with the NIST Neutron Physics Group.

Access & Resources

Planning Tools

Submit a Proposal

  • For submitting proposals, ideas, and questions contact the instrument scientist directly: michael.huber [at] nist.gov (michael[dot]huber[at]nist[dot]gov). Beamtime is awarded based on NIOF availability, novelty, and scientific impact. Generally, awarded experiments are allowed full use of the NIOF until such time the experiment is completed.

Instrument Contacts

michael.huber [at] nist.gov (michael[dot]huber[at]nist[dot]gov)
(301) 975-5641
shannon.hoogerheide [at] nist.gov (shannon[dot]hoogerheide[at]nist[dot]gov)
(301) 975-8582
Created July 2, 2026, Updated August 27, 2026
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