Neutron Beam Structured Wave Generator Using Phase Gratings

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Solution Overview

Problem

Existing techniques are inadequate for imparting structured wave components to neutron beams due to the low refractive index of neutrons in common materials, requiring impractically large optics, limited spatial coherence, and low fluence rates, hindering the imaging of fine details and material characterization.

Innovation Solution

A structured wave generator using a substrate with an array of phase gratings, where the holographic profile's in-plane dimension matches or is smaller than the neutron beam's lateral coherence length, diffracting the neutron beam into structured waves such as OAM, Airy, or Bessel beams.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If refractive optics are used to impart structured wave components to neutron beams, then the structured wave component can be added, but the optics would need to be impractically large due to the low refractive index of neutrons in common materials

Engineering Contradiction:

Improvestructured wave componentVSAvoidoptics size

Core Design Contradiction:

Adaptability or versatilityVSLength of stationary object

Solution Approach 1:

The patent replaces refractive optics with diffractive optics (phase gratings) to generate structured neutron waves. Instead of relying on refraction which requires large尺寸的 optics due to low neutron refractive index, the invention uses diffraction from micro-fabricated phase gratings with dimensions on the order of micrometers to millimeters, making the system practically manageable while achieving the same structured wave generation goal.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If traditional neutron beam techniques are used, then the beam can be maintained, but the spatial coherence is limited to only a few micrometers, hindering fine detail imaging

Engineering Contradiction:

Improvebeam stabilityVSAvoidspatial coherence

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent segments the neutron beam into multiple diffraction orders using an array of phase gratings. Each grating element processes a portion of the beam, and the coherent superposition of diffracted waves from multiple gratings extends the effective spatial coherence length beyond the inherent micrometer-scale coherence of the source, enabling high-resolution imaging.

Inventive Principle:

Principle #1Segmentation

3Ease of operation

If conventional neutron imaging is used, then the imaging can be performed, but the spatial resolution is limited to at best a fraction of a millimeter due to neutron camera resolution

Engineering Contradiction:

Improveimaging capabilityVSAvoidspatial resolution

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent transforms the imaging problem from direct spatial resolution limitations to angular/directional information encoding. By creating structured waves with specific orbital angular momentum states, the system encodes spatial information in the angular distribution of diffracted neutrons, allowing super-resolution imaging that overcomes the pixelation limits of conventional neutron cameras.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

4Power

If powerful research reactors are used, then neutron beams can be produced, but the fluence rate remains limited, reducing signal intensity

Engineering Contradiction:

Improveneutron beam intensityVSAvoidfluence rate

Core Design Contradiction:

PowerVSProductivity

Solution Approach 1:

The patent merges the signals from multiple diffraction orders that carry structured wave information. By combining the intensity contributions from different diffraction paths and using the phase relationship between them, the system achieves enhanced signal intensity and improved signal-to-noise ratio, effectively increasing the usable fluence rate for imaging and characterization.

Inventive Principle:

Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables the generation of structured neutron waves with well-defined orbital angular momentum values, enhancing material characterization and interaction studies by increasing neutron intensity and spatial resolution, overcoming limitations of existing technologies.

Implementation Method 1

when the neutron beam interacts with the array of phase gratings, at least a portion of the neutron beam diffracts to form a structured wave

Methodology Applied

Scientific EffectDiffraction: Diffraction

Data Source

PatentUS20240221969A1Structured wave generator and device for diffracting a neutron beam into a structured wave

Publication Date: 2024.07.04 INCOHERENT VISION INC

AI summary

There is described a structured wave generator generally having a neutron source generating a neutron beam having a propagation axis and a lateral coherence length extending perpendicular to the propagation axis; and a substrate spaced-apart from the neutron source, the substrate having an array of phase gratings distributed on the substrate for receiving the neutron beam, each phase grating having a body made of a grating material and having a holographic profile, the holographic profile having an in-plane dimension being equal or smaller than the lateral coherence length of the neutron beam, wherein when the neutron beam interacts with the array of phase gratings, at least a portion of the neutron beam diffracts to form a structured wave.