Ultra-small Angle X-ray Scattering Apparatus with Multilayer Paraboloid Mirror
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Solution Overview
Problem
Conventional X-ray small angle scattering measuring apparatuses, including those with Bonse-Hart optical systems, struggle to accurately capture scattered rays in ultra-small angle regions due to smearing phenomena caused by uncontrolled divergence of X-rays in the latitudinal direction, leading to blurred patterns and obscured peak information essential for analyzing aggregate structures of polymer materials.
Innovation Solution
An ultra-small angle X-ray scattering measuring apparatus is designed with a multilayer film paraboloid mirror collimating system that collimates X-rays in both longitudinal and transverse directions, using a pair of orthogonally arranged mirrors with alternating heavy and light element layers, and a monochromator and analyzer formed from perfect crystals, to produce a two-dimensionally collimated, highly intense monochromatic X-ray beam, thereby suppressing smearing and enhancing resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional slit type or Bonse-Hart optical system is used, then the apparatus structure is relatively simple, but the divergence angle of X-rays cannot be narrowed sufficiently while maintaining intensity, causing smearing in ultra-small angle region
Solution Approach 1:
The optical system is divided into multiple functional components: a first slit for initial beam limitation, a compound refractive index prism for divergence control, and a second slit for final beam definition. This segmentation allows each component to address specific aspects of beam control, achieving narrow divergence angle while maintaining sufficient intensity and preventing smearing in the ultra-small angle region.
2Measurement precision
If X-ray beam divergence is reduced to capture ultra-small angle scattered rays, then measurement precision improves, but the intensity of X-rays decreases, making background removal difficult
Solution Approach 1:
The compound refractive index prism introduces spatially varying refractive properties to locally control the divergence of X-rays. By designing the prism with specific refractive index gradients, the system achieves precise control over beam divergence in different regions, allowing narrow divergence angle while maintaining sufficient intensity through optimized local refractive effects.
3Measurement precision
If background is reduced to capture scattered rays in ultra-small angle region, then measurement precision improves, but the apparatus complexity increases due to additional optical components
Solution Approach 1:
The compound refractive index prism serves as an intermediary element between the slits and the sample. It mediates the interaction between the X-ray beam and the optical system by providing continuous divergence control, enabling effective background reduction without requiring additional complex components such as multiple slits or absorbers.
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
This configuration allows for clear capture of scattered ray patterns in ultra-small angle regions (2θ ≤ 0.08°), enabling accurate analysis of electron density and structural features of aggregates down to 200 nm to 1 µm, with improved intensity and reduced background noise, and the ability to observe diffracted rays in both equatorial and latitudinal directions.
Implementation Method 1
the multilayer film has a profile of a paraboloid, and is comprised of lattice planes having an interplanar spacing(d), the interplanar spacing(d) of the lattice planes of the multilayer film being made to continuously change along the paraboloid so as to satisfy the Bragg's condition for diffraction at any arbitrarily selected position on the X-ray reflection surface relative to X-rays of a specific wavelength
Implementation Method 2
a monochromator arranged between the X-ray real focus and the sample support device; and an analyzer arranged between the sample support device and the X-ray detection device, wherein the monochromator and the analyzer each have a pair of oppositely disposed X-ray reflection surfaces and are formed of a perfect crystal
Implementation Method 3
an X-ray generation device for taking out X-rays radiated from an X-ray real focus (F) with a predetermined focus size and emitting them toward the sample(S)
Implementation Method 4
an X-ray detection device for detecting X-rays emitted from the sample(S)... observe the change in the intensity I of scattered rays that corresponds to the change of 2θ-angle
Data Source
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AI summary
An ultra-small angle X-ray scattering measuring apparatus includes a detector for detecting X-rays emitted from a sample, an x-ray collimating mirror arranged between the X-ray real focus and the sample, a monochromator arranged between the X-ray collimating mirror and the sample and an analyzer arranged between the sample and the detector. The X-ray collimating mirror includes a pair of X-ray mirrors that are arranged orthogonally relative to each other. The X-ray mirrors are multilayer film mirrors and their X-ray reflection surfaces are paraboloidal. The interplanar spacing of lattice planes of each of the multilayer films is continuously changed along the paraboloid so as to meet the Bragg's condition. The monochromator and the analyzer are formed by using a channel-cut crystal. The analyzer is driven to rotate for scanning around a 2θ-axial line and diffracted rays reduced to a spectrum by the analyzer are detected by the detector.