Pushing the limits of microfocus X-ray sealed-tube sources for crystallography
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2021-08-14 |
| Journal | Acta Crystallographica Section A Foundations and Advances |
| Authors | J. Graf, Tobias Stuerzer, Matthew M. Benning, Roger Durst, P. Radcliffe |
| Institutions | Bruker (United States), Bruker (Germany) |
| Analysis | Full AI Review Included |
Technical Documentation: Diamond Hybrid Anodes for High-Brilliance X-Ray Sources
Section titled âTechnical Documentation: Diamond Hybrid Anodes for High-Brilliance X-Ray SourcesâExecutive Summary
Section titled âExecutive SummaryâThis research highlights the critical role of MPCVD diamond in overcoming the thermal limitations of microfocus X-ray sealed tube sources, enabling significantly brighter and more stable instrumentation for crystallography.
- Thermal Management Breakthrough: Industrial diamond, possessing thermal conductivity up to 5 times higher than copper, is utilized as a high-efficiency heat sink directly coupled to the anode material.
- Diamond Hybrid Anode: A novel structure consisting of a thin metal target layer deposited onto a bulk industrial diamond substrate dramatically improves heat dissipation and power density handling.
- Performance Parity: The resulting I”S DIAMOND source achieves X-ray intensities (1 * 1011 phts/s/mm2) comparable to modern 1 kW microfocus rotating anodes.
- Exceptional Stability: The balanced heat management ensures minimal intensity degradation, reporting only a few percent loss over 10,000 hours of full power operation.
- Operational Comfort: The superior thermal performance allows the high-power source to be reliably air-cooled, maintaining the convenience of a conventional sealed tube system.
- Application Impact: This innovation significantly enhances data quality for chemical and biological crystallography, particularly for structure determination of small and weakly diffracting crystals.
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points were extracted regarding the performance and material properties critical to the diamond hybrid anode technology:
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Diamond Thermal Conductivity | Up to 5 | Times Higher | Compared to Copper (Cu) |
| Achieved X-ray Intensity (I”S) | 1 * 1011 | phts/s/mm2 | Intensity delivered on the sample |
| Operational Lifetime (Full Power) | 10,000 | h | Demonstrated stability period |
| Intensity Degradation (Lifetime) | Few | Percent | Loss over 10,000 h of operation |
| Equivalent Performance | 1 | kW | Matches modern microfocus rotating anode power |
| Cooling Requirement | Air | Cooled | Enabled by diamond heat spreading |
| Target Layer Structure | Thin Layer | N/A | Metal deposited onto bulk diamond |
Key Methodologies
Section titled âKey MethodologiesâThe successful implementation of the high-brilliance microfocus X-ray source relies on advanced material engineering and system optimization, centered around the diamond hybrid anode concept:
- Diamond Substrate Integration: Utilizing bulk industrial diamond as the primary heat sink material, leveraging its superior thermal conductivity for efficient heat transfer away from the focal spot.
- Hybrid Anode Fabrication: Creating a composite structure by depositing a thin layer of the metallic X-ray target material directly onto the diamond substrate. This ensures high power density acceptance without damaging the target surface.
- Thermal Balancing: Designing the system for balanced heat management, allowing for air-cooling while maintaining long-term operational stability and minimizing intensity degradation over extended use.
- X-ray Optics Optimization: Combining the high-power anode with advanced multilayer mirror technology and optimizing the X-ray takeoff angle to maximize intensity delivery and match the divergence requirements of weakly diffracting samples.
- Cathode Parameter Tuning: Adjusting the filament parameters of the cathode to precisely match the requirements of the X-ray optics, enabling a significant overall increase in intensity on the sample.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & Capabilitiesâ6CCVD is uniquely positioned to supply the high-quality MPCVD diamond materials and precision fabrication services required to replicate, scale, and advance the diamond hybrid anode technology described in this research.
Applicable Materials
Section titled âApplicable MaterialsâThe core requirement is a high-purity, high-thermal-conductivity diamond substrate capable of acting as a robust heat spreader.
- High Thermal Conductivity Polycrystalline Diamond (PCD): Ideal for bulk industrial heat sink applications where large area and high thermal performance (up to 2000 W/mK) are paramount. 6CCVD offers PCD substrates up to 125mm in diameter.
- Electronic Grade Single Crystal Diamond (SCD): Recommended for applications requiring the absolute highest thermal conductivity (up to 2200 W/mK) and superior surface quality, especially if the target layer requires epitaxial growth or ultra-smooth interfaces (Ra < 1nm).
- Substrate Thickness: 6CCVD provides bulk substrates up to 10mm thick, ensuring robust mechanical and thermal support for high-power X-ray anodes.
Customization Potential
Section titled âCustomization PotentialâThe diamond hybrid anode requires precise material deposition and dimensional control, which are standard 6CCVD capabilities:
| Requirement from Paper | 6CCVD Capability | Specification Range |
|---|---|---|
| Bulk Substrate Size | Custom Dimensions | Plates/wafers up to 125mm (PCD) |
| Substrate Thickness | Bulk Material Supply | Substrates up to 10mm |
| Thin Metal Layer Deposition | Custom Metalization | Au, Pt, Pd, Ti, W, Cu (and alloys) |
| Surface Finish | Precision Polishing | Ra < 5nm (Inch-size PCD) |
| Geometry | Custom Laser Cutting | Complex shapes and precise hole drilling for mounting/cooling channels |
Engineering Support
Section titled âEngineering SupportâThe development of high-power X-ray instrumentation, thermal management systems, and high-frequency electronics relies heavily on optimizing the diamond-metal interface.
- 6CCVDâs in-house PhD team specializes in material selection, thermal modeling, and interface engineering for high-power density applications. We can assist researchers in selecting the optimal diamond grade (SCD vs. PCD) and metalization stack (e.g., Ti/W adhesion layers for Cu/Au targets) necessary for similar X-ray Instrumentation and Crystallography projects.
- We offer global shipping (DDU default, DDP available) to ensure rapid delivery of custom diamond components worldwide.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
The structure determination on ever smaller and weakly diffracting crystals is one of the biggest challenges in the development of inhouse X-ray analytical equipment for chemical and biological crystallography, which continuously raises the requirements for modern X-ray sources and detectors.Nowadays, modern low power microfocus X-ray sealed tube sources define the state-of-theart for most in-house X-ray diffraction equipment, as they deliver intensities in the range of rotating anodes, yet maintain all the comfort of a sealed tube system.Throughout the past years, we have continuously explored the physical limitations of impact ionization sources in order to find ways to push or even overcome some of the limitations, such as the heat transfer in the anode, leading to brighter X-rays sources with solid targets.The brightness of an X-ray tube is mainly limited by the thermal conductivity of the bulk anode material.As the thermal conductivity of diamond is up to about 5 times higher than that of copper and the highest known conductivity of all bulk materials [1], industrial diamond is increasingly replacing traditional materials for the thermal management in challenging applications [2], in which a high local heat load needs to be dissipated, such as in heat sinks for high-power microelectronic devices [3,4].In X-ray sources, diamond can be used as a heat sink directly coupled to the anode material, resulting in a significantly higher thermal conductivity compared to a conventional metallic anode and, hence, allowing for an increase in tube brilliance by applying a higher power load on the anode [5].As a result of our efforts, we recently introduced a unique new class of microfocus sealed tube X-ray sources that uses a novel anode technology, the diamond hybrid anode [6].It consists of a thin layer of metal deposited onto a bulk industrial diamond which acts as a heat spreader and significantly improves the heat dissipation in the anode.Consequently, the anode can accept a higher power density in the focal spot on the target without damaging the surface of the target layer.The balanced heat management allows the source to be aircooled, while assuring that the intensity loss over time is only a few percent over 10,000 h of full power operation, which is significantly lower than the intensity degradation observed for microfocus rotating anodes [7,8].Along with this, optimizing the takeoff angle of the anode and the filament parameters of the cathode to match the requirements of the X-ray optics enables a significant increase in the intensity on the sample.In combination with the latest developments in multilayer mirror technology, the I”S delivers an intensity in the range of 1âą10 11 phts/s/mm 2 with a divergence that matches the typical mosaicity of weakly diffracting samples.Therefore, the IÎŒS DIAMOND combines the performance of a modern 1 kW microfocus rotating anode with all the comfort of a conventional microfocus sealed tube source.We will be reviewing the latest innovations in microfocus sealed tube X-ray sources and multilayer optics and be presenting selected results from protein and pharmaceutical crystallography that demonstrate the impact of these recent developments on the data quality.