Enhanced tunable X-rays from bulk crystals driven by table-top free electron energies
Qingwei Zhai1, Nikhil Pramanik1, Ruihuan Duan2
1School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, Singapore.
Nature Communications
|December 11, 2025
Summary
Tunable X-ray generation is now feasible with bulk crystals, challenging prior beliefs. Bulk van der Waals crystals enable efficient, table-top X-ray sources for diverse applications.
Area of Science:
- Materials Science
- Physics
- X-ray Technology
Background:
- Free-electron-driven crystalline materials offer tunable, table-top X-ray generation.
- Bulk crystals were previously considered unsuitable for table-top X-ray sources due to bremsstrahlung background.
- Weakly relativistic energies from table-top sources were thought to exacerbate background noise.
Purpose of the Study:
- To challenge the notion that bulk crystals are infeasible for table-top X-ray generation.
- To identify conditions under which tunable X-rays dominate bremsstrahlung in bulk materials.
- To explore the potential of van der Waals crystals for enhanced X-ray generation.
Main Methods:
- Introduction of a parameter to define a regime favoring tunable X-rays over bremsstrahlung.
- Theoretical analysis of electron scattering in bulk crystalline materials.
- Experimental validation using bulk van der Waals crystals.
Main Results:
- A regime was identified where tunable X-rays significantly exceed bremsstrahlung in bulk materials.
- Van der Waals crystals were shown to readily access this regime, exhibiting unique X-ray properties.
- A tenfold intensity enhancement was experimentally demonstrated using bulk van der Waals crystals.
Conclusions:
- Bulk van der Waals crystals are suitable for table-top, tunable X-ray generation.
- This overcomes previous limitations associated with bremsstrahlung background.
- Findings enable more accessible and efficient X-ray sources for industrial and medical imaging.
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