BT1 High Resolution Powder Diffractometer

Instrument Purpose

Provides precise determination of atomic and magnetic structures in polycrystalline materials using high-resolution neutron powder diffraction.

Key Capabilities

• Tailored Resolution: Features three interchangeable monochromators, allowing users to tailor the instrument response (intensity vs. resolution) specifically to their sample's needs.
• Excellent Data Quality: Produces nearly perfect Gaussian peak shapes, simplifying the modeling of complex multi-phase materials and subtle symmetry lowering.
• Exceptional Environment Flexibility: BT1 is highly regarded for its ability to run samples under a versatile range of specialized sample environments.
• Mail-in Program: The NCNR offers a robust mail-in service where NIST scientists collect data for you. This service is ideal for basic crystallographic needs (5 K – 300 K) and saves the time and cost of traveling to the facility.

Research Domains

• Energy Storage: Investigating and determining small gas molecules in the pores of zeolites and metal-organic frameworks (MOFs), lithium and sodium ion environments within battery electrode materials, and hydrogen or deuterium sites within a host material lattice.
• Quantum Materials & Magnetism: Tracking magnetic phase transitions and magnetic order; identifying and solving magnetic structures.
• Advanced Functional Materials: Precise determination of oxygen vacancies and structural distortions in superconductors, subtle lattice distortions in ferroelectric and piezoelectric materials, and lattice changes in negative thermal expansion (NTE) materials.
• Ceramics & Intermetallics: Precise determination of stoichiometry in oxides, and site-ordering of different metals in an alloy. Analysis of phase fractions and thermal expansion over wide temperature ranges.

What You Can Measure

• Precise crystal structures (unit cell dimensions, atomic positions, light atom detection, occupancies/vacancies, and thermal parameters).
• Magnetic structure and moment determination.
• Phase identification and quantification in complex mineralogical or industrial samples.
• Structural changes under external stimuli (temperature, magnetic field, pressure, gas-loading, and electric field).

Technical Specifications

Specialized Sample Environments

• Extreme Temperatures: Seamless integration with NCNR’s sample environment suite, covering 0.05 K to 2000 K via dilution refrigerators, cryostats, and specialized furnaces.
• Magnetic Fields: Vertical fields (up to 7 T) for probing magnetic phase diagrams.
• Gas Loading & In-Situ: Specialized cells for gas adsorption (H₂/D₂, CO₂, etc.) and high-pressure environments (up to 2.5 GPa).
• Standard Containers: Vanadium cans in various sizes (1.5 mL, 4.0 mL, 5.5 mL, 8.0 mL, 11.5 mL), optimized for low background.

Expertise & Support

• On-Site Scientists: Our instrument scientists are international experts in structure determination from powder samples, Rietveld refinement, and magnetic crystallography. They provide hands-on assistance from experimental design to final publication.
• Data Reduction: Automated software pipelines convert raw detector counts into standard formats (GSAS, FullProf) with built-in absorption and background corrections.
• NIST Data Tools: Specialized Python scripts for real-time monitoring of thermal equilibrium and field dependence.

Access & Resources

Instrument Contacts