The upgraded Polaris powder diffractometer at the ISIS neutron source.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Neutron Scattering

Background:

• The Polaris time-of-flight powder neutron diffractometer at ISIS is a key instrument for materials research.
• Previous limitations in detector coverage and count rates restricted certain experimental capabilities.

Purpose of the Study:

• To describe the design and operation of the upgraded Polaris diffractometer.
• To highlight the benefits of enhanced detector coverage and count rates.
• To showcase improved capabilities for in situ and total scattering studies.

Main Methods:

• Installation of five large ZnS scintillator-based detector banks.
• Achieved wide angular coverage (6° ≤ 2θ ≤ 168°) with minimal gaps.
• Implementation of a novel radial collimator and advanced sample environment.

Main Results:

• Substantially increased solid angle coverage (Ω ∼ 5.67 sr).
• Achieved 2x to 10x increase in count rates depending on 2θ angle.
• Demonstrated enhanced performance for small sample, time-resolved, in situ, and total scattering experiments.

Conclusions:

• The upgraded Polaris diffractometer offers significantly improved performance for a range of neutron scattering experiments.
• Enhanced capabilities facilitate advanced materials characterization, including in situ and disordered materials studies.
• The instrument is well-suited for rapid investigations and studies involving small sample volumes.