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NG5 POLAR
Instrument Purpose
To serve as NCNR’s flagship next-generation cold neutron spectrometer, optimized for high-intensity polarized inelastic scattering and large-area reciprocal space mapping of quantum materials while maintaining exceptional control of instrumental resolution.
The NCNR Advantage
- Successor to a Legacy: PoLAR replaces the SPINS (Spin Polarized Inelastic Neutron Spectrometer), leveraging decades of expertise in triple-axis spectroscopy while introducing a massive leap in performance.
- Advanced Guide Technology: Situated on the newly installed NG-5 supermirror elliptical guide, engineered to generate an ideal "virtual source" for the double focusing monochromator. Together, this coupled design concentrates a cold neutron flux on the sample nearly an order of magnitude higher than its predecessor.
- Multiplexed Analyzer and PSD: Energy analysis after the sample utilizes a multi-blade crystal analyzer assembly capable of measuring ~10 degrees of scattering. The analyzer system can operate in multiple different geometries, allowing users to select between constant energy cuts in reciprocal space or dispersive cuts over a 1meV range with a total collection an order of magnitude greater than traditional single detector triple axis.
Research Domains
- Quantum Magnetism: Mapping spin-wave dispersions in frustrated magnets and 2D materials.
- Superconductivity: Exploring the role of spin fluctuations in the pairing mechanisms of high-Tc materials.
- Multiferroics: Investigating the coupling between magnetic and electric order parameters.
- Topological Matter: Probing magnetic chirality and excitations of topological materials such as topological insulators, altermagnets, spin liquids and Weyl semimetals.
- Soft Matter: Utilization of polarized neutrons to separate of coherent scattering (coherent motion) and incoherent scattering (uncorrelated diffusion).
What You Can Measure
- Polarized Inelastic Scattering: Disentanglement of complex magnetic systems with definitive separation of magnetic, nuclear coherent, and nuclear incoherent cross-sections by supporting multiple polarization techniques including P//Q, P⟂Q, and xyz-polarization analysis.
- Reciprocal Space Mapping: High-speed, high-resolution surveys of (Q, E) space.
- Sub-meV Dynamics: Precise determination of low-energy gap structures and excitation lifetimes.
Technical Specifications
| Parameter | Specification |
|---|---|
| Source Type | Cold Neutrons (New NG-5 Elliptical Guide) |
| Monochromator | 400 cm2 Double-Focusing Monochromator (DFM) Array of 2 cm x 2 cm HOPG crystals (PG-002 and PG-004) |
| Flux at Sample | ~ 108 n/cm2/s (Estimated) |
| Polarization | High-efficiency supermirror transmission polarizer and analyzer with the option to increase polarization further with 3He spin filters. |
| Incident Energies | 2.5 meV to 15 meV (with unpolarized beam only above 15meV) |
| Final Energies | 2.5 meV to 5 meV (with >5meV achievable in single detector mode) |
| Energy Transfer | Optimized for 0.05 meV (highest resolution) to 12.5 meV (polarized) |
| Detector | 84 8mm tube array (~37 tubes measured simultaneously) |
Specialized Sample Environments
- High-Field Magnets: Full integration with NCNR’s 15 Tesla superconducting magnets.
- Sub-Kelvin Access: Optimized for Dilution Refrigerators (< 50 mK) to probe quantum critical points.
- High-Pressure Cells: Specialized support for clamp cells and anvil cells to study structural and magnetic transitions under pressure.
Expertise & Support
- Future-Ready Science: The PoLAR team is currently leading the "clean run" upgrade program, ensuring the instrument is integrated with the latest in NICE (Instrument Control) software and DAVE visualization tools.
- Advanced Simulation Capability: Monte-Carlo simulation and fitting of theoretical physical models directly to the multidimensional inelastic neutron scattering data including convolution of instrument resolution, multiple scattering with ab-initio inclusions of diffraction and phonons in an ecosystem integrated within NICE and DAVE.
- The NIST Standard: As with all NCNR instruments, PoLAR is designed with metrological rigor, providing absolute intensity measurements that allow for direct comparison with theoretical models and simulations.
- Staff Expertise: Instrument scientists specialize in advanced polarization analysis and the synthesis of high-quality single crystals for quantum research.
Access & Resources
Status
- Under Construction/Upgrade
- ECD: Commissioning 2029; User Program 2030
Submit a Proposal
- N/A
Instrument Contacts
Created August 27, 2026