1
|
Gao Z, Fan J, Tong Y, Zhang J, He B, Nie Y, Luan H, Lu D, Zhang D, Yuan X, Wang Y, Liu Z, Jiang H. Single-pulse characterization of the focal spot size of X-ray free-electron lasers using coherent diffraction imaging. JOURNAL OF SYNCHROTRON RADIATION 2023; 30:505-513. [PMID: 36947163 PMCID: PMC10161889 DOI: 10.1107/s1600577523000887] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 01/31/2023] [Indexed: 05/06/2023]
Abstract
The characterization of X-ray focal spots is of great significance for the diagnosis and performance optimization of focusing systems. X-ray free-electron lasers (XFELs) are the latest generation of X-ray sources with ultrahigh brilliance, ultrashort pulse duration and nearly full transverse coherence. Because each XFEL pulse is unique and has an ultrahigh peak intensity, it is difficult to characterize its focal spot size individually with full power. Herein, a method for characterizing the spot size at the focus position is proposed based on coherent diffraction imaging. A numerical simulation was conducted to verify the feasibility of the proposed method. The focal spot size of the Coherent Scattering and Imaging endstation at the Shanghai Soft X-ray Free Electron Laser Facility was characterized using the method. The full width at half-maxima of the focal spot intensity and spot size in the horizontal and vertical directions were calculated to be 2.10 ± 0.24 µm and 2.00 ± 0.20 µm, respectively. An ablation imprint on the silicon frame was used to validate the results of the proposed method.
Collapse
Affiliation(s)
- Zichen Gao
- School of Physical Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Shanghai 201210, People's Republic of China
| | - Jiadong Fan
- Center of Transformative Science, ShanghaiTech University, 393 Middle Huaxia Road, Shanghai 201210, People's Republic of China
| | - Yajun Tong
- Center of Transformative Science, ShanghaiTech University, 393 Middle Huaxia Road, Shanghai 201210, People's Republic of China
| | - Jianhua Zhang
- Center of Transformative Science, ShanghaiTech University, 393 Middle Huaxia Road, Shanghai 201210, People's Republic of China
| | - Bo He
- School of Physical Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Shanghai 201210, People's Republic of China
| | - Yonggan Nie
- Center of Transformative Science, ShanghaiTech University, 393 Middle Huaxia Road, Shanghai 201210, People's Republic of China
| | - Hui Luan
- Center of Transformative Science, ShanghaiTech University, 393 Middle Huaxia Road, Shanghai 201210, People's Republic of China
| | - Donghao Lu
- School of Physical Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Shanghai 201210, People's Republic of China
| | - Difei Zhang
- School of Physical Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Shanghai 201210, People's Republic of China
| | - Xinye Yuan
- School of Physical Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Shanghai 201210, People's Republic of China
| | - Yueran Wang
- School of Physical Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Shanghai 201210, People's Republic of China
| | - Zhi Liu
- School of Physical Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Shanghai 201210, People's Republic of China
| | - Huaidong Jiang
- School of Physical Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Shanghai 201210, People's Republic of China
| |
Collapse
|
2
|
Li K, Liu Y, Seaberg M, Chollet M, Weiss TM, Sakdinawat A. Wavefront preserving and high efficiency diamond grating beam splitter for x-ray free electron laser. OPTICS EXPRESS 2020; 28:10939-10950. [PMID: 32403615 DOI: 10.1364/oe.380534] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 02/28/2020] [Indexed: 06/11/2023]
Abstract
X-ray free electron lasers (XFELs) provide femtosecond high-power x-ray beams with high spatial coherence, resulting in numerous influential discoveries. Diffractive optics allow for the easy manipulation and measurement of an x-ray beam's wavefront and enable the realization of complex designed properties and specifications. For example, phase gratings can be used as x-ray beam splitters to enable beam sharing by multiple end stations or in-situ beam monitoring, including spectrum and wavefront measurements. Wavefront preservation and high efficiency and survivability under high power are requirements for such beam splitters. Diamond is the most suitable choice for phase grating fabrication, due to its high thermal conductivity that enables it to survive high average power XFEL beams. We have fabricated a large area (2×2 mm2) high aspect ratio (13:1) diamond grating on a diamond plate. Testing was performed at 9.5 keV and resulted in a high splitting efficiency (30%). Tunable efficiency was obtained via tilting the grating with respect to the x-ray beam. Wavefront fidelity of the split beams were measured to less than λ/100 using a Talbot wavefront sensor.
Collapse
|