High-resolution ptychographic nanoimaging under high pressure with X-ray beam scanning
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2025-10-24 |
| Journal | Proceedings of the National Academy of Sciences |
| Authors | Tang Li, Ken Vidar Falch, Jan Garrevoet, Leonid Dubrovinsky, Mikhail Lyubomirskiy |
| Institutions | Deutsches Elektronen-Synchrotron DESY, University of Bayreuth |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: High-Resolution Ptychographic Nanoimaging
Section titled âTechnical Documentation & Analysis: High-Resolution Ptychographic NanoimagingâExecutive Summary
Section titled âExecutive SummaryâThis research demonstrates a significant advancement in X-ray ptychography, critically enabling high-resolution imaging under extreme physical conditions, a field heavily reliant on high-quality diamond materials.
- Novel Methodology: The study introduces a beam-scanning approach using reflective optics (tilting mirror) to replace conventional sample scanning, thereby eliminating the major limitation imposed by heavy/bulky sample environments, such as Diamond Anvil Cells (DACs).
- Extreme Conditions Achieved: Successfully performed in situ phase-contrast nanoimaging of iron (Fe) oxidation and melting at extreme conditions: 51(2) GPa pressure and 2,350 K temperature.
- High Resolution: Achieved a photon statistics limited resolution of 42 nm (edge response) and visualized intricate material details at sub-50 nm resolution.
- Phase Contrast: The method provides high-sensitivity phase contrast, essential for visualizing subtle changes (e.g., melting fronts, chemical reactions) in metallic density where absorption contrast is insufficient.
- Material Criticality: The success of the experiment hinges on the mechanical strength and X-ray transparency of the DAC anvils, requiring high-purity Single Crystal Diamond (SCD).
- Application Scope: This breakthrough opens new avenues for operando nanoscopy in high-pressure physics, geoscience, and materials synthesis, where static or low-resolution imaging methods fail.
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points were extracted from the experimental results and setup description:
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Maximum Pressure Achieved | 51(2) | GPa | Fe oxidation experiment in DAC |
| Laser Heating Temperature | 2,350(150) | K | Applied for 2 s to induce Fe melting/oxidation |
| Achieved Spatial Resolution | 42 | nm | Edge response (Siemens Star validation, 12.3 keV) |
| Visualization Resolution | Sub-50 | nm | Resolution achieved for Fe oxidation visualization |
| X-ray Energy (Validation) | 12.3 | keV | Mirror scan (Siemens Star) |
| X-ray Energy (Experiment) | 13 | keV | DAC scan |
| DAC Diamond Culet Size | 250 | ”m | Flat culets used on Boehler-Almax diamonds |
| Fe Foil Thickness | 3 | ”m | Initial thickness before compression |
| Scanning Mirror Coating | 35 nm Ru | - | Total reflective mirror coating |
| Detector Pixel Size | 75 | ”m | Eiger detector (2,048 x 2,048 pix) |
| Effective Beam Integration Length | 96 | nm | Used for mirror scan on the sample |
Key Methodologies
Section titled âKey MethodologiesâThe high-resolution ptychography was achieved through a combination of specialized high-pressure apparatus and novel beam-scanning techniques:
- Pressure Apparatus: A BX-90 Diamond Anvil Cell (DAC) was utilized, featuring Boehler-Almax diamonds with 250 ”m flat culets affixed to tungsten carbide seats.
- Sample Environment: Iron (Fe) foil (3 ”m thick) was placed in a Rhenium (Re) gasket chamber (110 ”m diameter) and cryogenically loaded with O2, which served as both the pressure medium and chemical reactant.
- Extreme Condition Generation: Pressure was set to 51(2) GPa. Laser heating was applied using a double-sided near-infrared laser focused to 7 ”m FWHM, achieving 2,350(150) K.
- X-ray Focusing: The X-ray beam was focused using Kirkpatrick Baez (KB) mirrors, providing a 200 mm working distance.
- Beam Scanning Mechanism: Ptychography scanning was performed by tilting a 35 nm Ruthenium (Ru) coated reflective mirror (placed 110 mm from the sample) to oscillate the beam vertically (fast axis). The sample stage provided horizontal translation (slow axis).
- Position Tracking: Two laser interferometers monitored the angular motion of the reflective mirror with subnanometer precision, allowing for highly accurate determination of the X-ray beam position on the sample plane.
- Reconstruction: Ptychographic reconstructions utilized a combination of ePIE and maximum likelihood algorithms, with position refinement to compensate for variable aberrations introduced by the tilting mirror.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThe success of high-pressure X-ray nanoimaging relies fundamentally on the quality and precision of the diamond components used in the DACs. 6CCVD is uniquely positioned to supply the necessary materials and customization required to replicate and extend this cutting-edge research.
Applicable Materials
Section titled âApplicable MaterialsâTo achieve the extreme pressures and maintain the required X-ray transparency (13 keV), the DAC anvils must be fabricated from the highest quality diamond.
- Optical Grade Single Crystal Diamond (SCD): This material is essential for DAC anvils. 6CCVD provides high-purity SCD with extremely low nitrogen content, ensuring minimal X-ray absorption and low birefringence, which is critical for maintaining the coherence and phase sensitivity required for ptychography.
- Boron-Doped Diamond (BDD): For future extensions involving electrical measurements in situ (e.g., conductivity under pressure), 6CCVD offers BDD substrates, which can be custom-doped to provide conductive contacts while maintaining high mechanical strength.
Customization Potential
Section titled âCustomization PotentialâThe research utilized specific DAC geometries and a custom-coated mirror. 6CCVD offers comprehensive customization services to meet these precise engineering requirements:
| Research Requirement | 6CCVD Customization Capability |
|---|---|
| Custom Anvil Geometry | We supply custom SCD plates/wafers up to 500 ”m thick, precision-cut and shaped for specific DAC designs (e.g., 250 ”m culets or beveled geometries for TPa experiments). |
| Surface Finish | The SCD anvils require ultra-smooth surfaces to minimize X-ray scattering and phase distortion. Our SCD polishing achieves Ra < 1 nm. |
| Custom Metalization | The reflective optics utilized a 35 nm Ru coating. 6CCVD offers in-house metalization (Au, Pt, Pd, Ti, W, Cu) for creating custom X-ray reflective surfaces or electrical contacts directly on diamond substrates. |
| Large Area PCD | While SCD is preferred for the anvils, 6CCVD can supply large Polycrystalline Diamond (PCD) plates up to 125 mm in diameter, polished to Ra < 5 nm, suitable for large-scale X-ray windows or heat management components in the beamline setup. |
Engineering Support
Section titled âEngineering SupportâThe complexity of integrating high-pressure environments with advanced X-ray optics demands expert material consultation.
- High-Pressure Physics Expertise: 6CCVDâs in-house PhD engineering team specializes in material selection and design optimization for High-Pressure Physics and Operando Nanoscopy projects. We assist researchers in selecting the optimal diamond grade (SCD purity, thickness, and culet geometry) to maximize pressure limits and X-ray transmission efficiency at specific keV energies.
- Global Logistics: We ensure reliable, global shipping (DDU default, DDP available) of sensitive, high-value diamond components directly to synchrotron radiation facilities (SRFs) worldwide.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
We present an approach to nanoscale-resolution high-sensitivity imaging of internal material structure under in situ/operando conditions for virtually any sample environment. When bulky or heavy sample environment is required state-of-the-art X-ray imaging techniques, such as scanning and full-field microscopy or holography fail to deliver high-resolution imaging capabilities due to either i) extremely small opticsâ working distance for magnification-based methods or ii) the inability to precisely control heavy sample position in the case of lens-less methods. In this work, we address those challenges for a scanning lens-less imaging method called ptychography. Instead of precisely controlling the sample position during raster scan in a focused, confined X-ray beam, we are scanning that beam across the sample. This overcomes the constraints on scanning procedure imposed by sample size/weight and delivers unmatched scanning speed while maintaining high precision of beam position during the scan. We directly applied our approach, showcasing phase contrast nanoimaging with diamond anvil cells, and visualized intricate details of the melting and oxidation of laser-irradiated iron under pressure of 50 GPa.