Numerical simulation of the diamond window of the synchrotron workstation. Choice of diamond foil thickness (0.2-1.0 mm)
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2023-01-01 |
| Journal | E3S Web of Conferences |
| Authors | M.V. Pukhovoy, V V Vinokurov, Viktor A. Vinokurov, Oleg Kabov |
| Institutions | Institute of Thermophysics |
| Citations | 2 |
| Analysis | Full AI Review Included |
Executive Summary
Section titled âExecutive SummaryâThis study details the finalization of the design and thermal management calculations for a Diamond Vacuum Window (DVW) intended for the Siberian Circular Photon Source (SKIF), a 4+ generation synchrotron.
- Core Challenge: Managing extreme heat loads (1290 W total, up to 1.5 kW/cm2 flux) generated by a superconducting wiggler while maintaining ultra-high vacuum (10-8 Pa) and minimizing thermal deformation (< 3.5 ”m).
- Cooling Solution: An efficient mini-channel water cooling system integrated into copper flanges, coupled with a CVD-diamond foil filter.
- Interface Technology: A 0.5 mm thick layer of liquid metal is used between the diamond foil and the copper flanges to simultaneously seal the vacuum and significantly reduce thermal contact resistance.
- Thermal Constraint: Detailed calculations require the maximum temperature (TMAX) in the diamond foil to remain below 320°C, providing a twofold safety margin against thermal stresses.
- Thickness Dependence: Simulations varying the diamond foil thickness (s) from 0.2 mm to 1.0 mm showed that TMAX increases significantly as s decreases. Thicknesses greater than approximately 0.4 mm are required to meet the 320°C safety limit.
- Future Work: The study highlights that heat absorption (W) is proportional to thickness. A more accurate selection of the final thickness requires detailed study of SR absorption based on the specific physical characteristics of the chosen CVD diamond supplier.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Synchrotron Generation | 4+ | N/A | SKIF Source (Novosibirsk) |
| Electron Beam Energy | 3 | GeV | SKIF Source |
| Total Radiation Power | 49 | kW | Generated by superconducting wiggler |
| Peak Power Density | 92 | kW/mrad2 | On the axis of the SR beam |
| Required Vacuum Level | 10-8 | Pa | Region cut off by DVW |
| Total Heat Absorption (DVW) | 1290 | W | Non-uniform heat load on diamond |
| Peak Heat Flux Density | 1.35 - 1.5 | kW/cm2 | Incident on diamond plate |
| Maximum Safe Operating Temperature | 320 | °C | Provides a twofold safety margin against thermal stress |
| Maximum Allowable Deformation | 3.5 | ”m | Thermal deformation constraint |
| Diamond Foil Thickness Range Studied | 0.2 to 1.0 | mm | Simulation variable |
| Liquid Metal Layer Thickness | 0.5 | mm | Used for sealing and thermal contact |
| Mini-Channel Dimensions | 0.5 x 1.0 | mm2 | Water cooling channels in copper flanges |
| Copper Flange Emissivity (Δ) | 0.02 | N/A | Polished copper |
| Diamond Glass Emissivity (Δ) | 0.92 | N/A | CVD diamond filter |
Key Methodologies
Section titled âKey MethodologiesâThe thermal management and stress analysis were conducted using the Finite Element Method (FEM) via the ANSYS Fluent package.
- Geometric Modeling: The computational domain included the CVD diamond foil, the 0.5 mm liquid metal layer, and the copper flanges containing the cooling system. The SR beam dimensions were 30 mm (horizontal) x 3 mm (vertical).
- Cooling System Design: Water cooling was implemented using mini-channels (0.5 x 1.0 mm2 cross-section) located within the copper flanges.
- Heat Load Application: A total heat absorption of 1290 W was applied to the diamond plate, based on a non-uniform heat flux distribution derived from experimental data (1.35 - 1.5 kW/cm2).
- Material Properties: Numerical calculations incorporated temperature-dependent properties for the diamond plate, specifically thermal conductivity and heat capacity (Cp).
- Fluid Dynamics: The unsteady k-omega turbulence model was employed for solving the flow dynamics within the mini-channels.
- Boundary Conditions: Outer boundaries were set to vacuum conditions (ambient temperature 22°C). Radiative heat transfer was modeled using specified emissivities (Δ = 0.02 for copper, Δ = 0.92 for diamond).
- Parameter Sweep: Simulations were run iteratively, varying the diamond foil thickness (s) from 0.2 mm to 1.0 mm to determine the resulting temperature profiles and maximum temperatures (TMAX).
- Verification: Calculation accuracy was confirmed by controlling the balance of heat flux across the boundaries and monitoring the mass imbalance within the system.
Commercial Applications
Section titled âCommercial ApplicationsâThe technology developed for the DVW cooling system is directly applicable to high-performance systems requiring precise thermal control under extreme heat loads and ultra-high vacuum.
- Synchrotron and X-ray Facilities: Essential for the design and operation of beamline components (filters, windows, mirrors) in 3rd and 4th generation light sources, managing high-power X-ray beams.
- High-Power Optics and Lasers: Applicable to thermal management of optical elements in high-power laser systems where thermal deformation must be strictly minimized (e.g., < 3.5 ”m).
- Advanced Vacuum Technology: The use of liquid metal interfaces provides a robust solution for simultaneous vacuum sealing and high-efficiency heat transfer in complex, high-vacuum environments (e.g., fusion reactors, particle accelerators).
- CVD Diamond Component Engineering: Demonstrates reliable integration and thermal management strategies for high-quality CVD diamond in mechanically and thermally stressed applications.
- Microchannel Heat Exchangers: The mini-channel cooling design (0.5 x 1.0 mm2 channels) serves as a validated model for high-density, localized heat dissipation in electronics and specialized industrial equipment.
View Original Abstract
Due to the high energy density in the synchrotron beam and the high cost of all elements of the synchrotron and workstations, due to the fact that most of the devices are in vacuum, as well as high requirements for the smallness of thermal deformations of optical elements, ensuring thermal management of any elements of workstations using synchrotron radiation (SR) is a unique, complex, non-standard task. The work is devoted to the finalizing of the previously performed detailed calculations of the cooling of the most heat-loaded optical elements of workstations of wiggler SR sources - diamond windows that cut off high vacuum (DVW).