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Failure Analysis of Batteries Using Synchrotron-based Hard X-ray Microtomography
Published on: August 26, 2015
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Hard X-ray self-seeding commissioning at PAL-XFEL
Chang Ki Min1, Inhyuk Nam1, Haeryong Yang1
1Pohang Accelerator Laboratory, Pohang, Gyeongbuk 37673, Republic of Korea.
Journal of Synchrotron Radiation
|July 6, 2019
Summary
A new diamond crystal monochromator for hard X-ray free-electron lasers (FELs) was successfully commissioned. This self-seeding technology significantly enhances spectral brightness and narrows bandwidth, improving FEL performance.
Area of Science:
- Physics
- Accelerator Science
- Materials Science
Background:
- Hard X-ray free-electron lasers (XFELs) are crucial for advanced research.
- Achieving high coherence and narrow bandwidth in XFELs is challenging.
- Self-seeding techniques are employed to improve XFEL beam quality.
Purpose of the Study:
- To install and commission a novel wake monochromator utilizing a large-area diamond single crystal for hard X-ray self-seeding.
- To demonstrate the effectiveness of the diamond crystal monochromator in enhancing the spectral brightness and narrowing the bandwidth of XFEL pulses.
- To validate the performance of the self-seeding system at different bunch charges.
Main Methods:
- Installation and commissioning of a wake monochromator with a 30 µm thick diamond single crystal at the Pohang Accelerator Laboratory XFEL.
- Demonstration of self-seeding with low (40 pC) and nominal (180 pC) bunch charges.
- Measurement of FEL pulse lengths, spectral brightness, and bandwidth using diagnostic tools.
Main Results:
- Successful commissioning of the diamond crystal monochromator for hard X-ray self-seeding.
- Achieved a narrow bandwidth of 0.22 eV (FWHM) at 8.3 keV, confirming the functionality of the thin crystal.
- Increased average spectral brightness by over three times compared to self-amplified spontaneous emission (SASE) mode.
- Observed a Gaussian intensity profile and minimal electron-energy jitter (∼1.2 × 10⁻⁴) in nominal bunch-charge operation, indicating saturated FEL performance.
Conclusions:
- The large-area diamond single crystal wake monochromator is a functional and effective component for hard X-ray self-seeding.
- The system significantly improves spectral brightness and narrows bandwidth, crucial for advanced XFEL applications.
- The results demonstrate the potential for enhanced XFEL performance through advanced monochromator and seeding technologies.
Keywords:
diamond monochromatorselectron-energy jitterfree-electron lasershard X-raysself-amplified spontaneous emissionself-seedingMore Related Videos
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