Design optimization of a periodic microstructured array anode for hard x-ray grating interferometry

Area of Science:

• Medical Imaging
• Materials Science
• Physics

Background:

• Talbot-Lau grating interferometers (TLGI) provide enhanced contrast in X-ray imaging, particularly for low-Z materials, surpassing conventional absorption contrast methods.
• Microstructured Array Anode Target (MAAT) sources offer higher imaging throughput compared to traditional setups involving extended X-ray sources and absorption gratings.

Purpose of the Study:

• To optimize the performance of MAAT sources by analyzing key parameters such as areal density, dimensions, and material selection for microstructured metal inserts (MMI) and substrates.
• To determine optimal MAAT parameters for incident electron energies ranging from 30 keV to 120 keV.
• To derive the maximum allowable electron-beam power loading for stable operation of transmission MAATs based on thermal analysis.

Main Methods:

• Monte Carlo simulations were employed to analyze X-ray generation efficiency, spectral distribution, and angular distribution.
• Finite element analysis was used to simulate the temperature distribution within the MAAT for optimized parameters.
• Performance metrics including X-ray generation efficiency per incident electron and the fraction of X-rays from MMI versus substrate were evaluated.

Main Results:

• Optimal parameters for MAAT performance were identified for electron energies between 30 keV and 120 keV.
• Simulation results provided insights into X-ray generation efficiency, spectrum, and angular distribution.
• Thermal analysis yielded the maximum allowable electron-beam power loading for stable transmission MAAT operation.

Conclusions:

• The study successfully identified optimal parameters for MAAT sources, enhancing their suitability for high-throughput X-ray imaging applications.
• The derived thermal loading limits ensure stable and reliable operation of transmission MAATs.
• Optimized MAAT sources, when used with TLGI, represent a significant advancement in X-ray imaging technology, especially for challenging materials.