Recently, rapid progresses have been made in Shanghai-XFEL Beamline Project (SBP) and Shanghai Soft X-ray Free Electron Laser Facility (SXEFL). Following the accelerator, undulator, and beamline commissioning, this 532-meter-long free electron laser facility is approaching in full operation and starts the data collection. On June 24th, the first single-shot coherent diffraction imaging (CDI) experiment (Figure 1) was performed in a “water window” (at a wavelength of 2.4 nm) and online image reconstruction was achieved. This progress symbolizes that X-ray FEL research in China has advanced from facility research and development phase to user operation phase. SXFEL (Figure 2) is now among the elite FEL user facility club.
Figure 1. Coherent diffraction imaging patterns of commissioning samples
The water window refers to a soft X-ray with a wavelength in the range of 2.3 - 4.4 nm. In this range, water is relatively transparent to X-rays. But other essential life elements, such as carbon, still interact strongly with X-rays. Therefore, the “water window” soft X-rays provide a unique opportunity for probing biological materials. Within the “water window”, SXFEL can generate high intensity free electron laser pulses, which are one billion times brighter than those of synchrotron radiation light sources. Such ultrabright, ultrafast, and coherent pulse enables scientists to take X-ray snapshots of atoms and molecules at work, revealing fundamental processes in materials, technology and living organisms. It will also provide a much needed boost for the research and development for the future FEL facility, such as Shanghai Hard X-ray FEL Facility (SHINE).
The construction of SXFEL consists of two concurrent projects: “Shanghai-XFEL Beamline Project” and “Shanghai Soft X-ray Free Electron Laser Facility”. With the aforementioned developments, SXFEL is joining Shanghai Synchrotron Radiation Facility (in operation), Shanghai Super Intense Ultrafast Laser Facility (in operation) and SHINE (under construction) as a new member of the photon science facility cluster, which is the core component of the global photon science research center in Zhangjiang, Pudong. Shanghai-XFEL Beamline Project is jointly constructed by ShanghaiTech University, Shanghai Institute of Applied Physics (SINAP), the Chinese Academy of Sciences (CAS) and Shanghai Advanced Research Institute (SARI), CAS. The project scope include the construction of one SASE undulator line (Figure 3), one SASE beamline, 5 endstations and supporting experimental facilities. The construction started in November 2016, and is expected to be in full operation at the end of 2021. The SXFEL facility is to start the user operation in 2022 and will open to both domestic and international users.
The Shanghai-XFEL Beamline Project and Shanghai Soft X-ray Free Electron Laser Facility have been jointly funded by National Development and Reform Commission and Shanghai Municipal Government.
Figure 2. Shanghai Soft X-ray Free Electron Laser Facility (SXFEL)
Figure 3. SBP SASE Undulators
Figure 4. The SBP SASE Beamline