Photo: Screenshot of a statement of ShanghaiTech University

China's first X-ray free electron laser device has acquired femtosecond "water window" band X-ray photos for the first time. 

The achievement was announced by ShanghaiTech University in a statement on Friday, which said that the progress symbolizes that X-ray FEL research in China has advanced from facility research and development phase to user operation phase which can compete globally.

Shanghai Soft X-ray Free Electron Laser Facility (SXEFL) performed the first single-shot coherent diffraction imaging experiment in a "water window" (at a wavelength of 2.4 nanometers) on Thursday and achieved online image reconstruction. 

The water window refers to a soft X-ray with a wavelength in the range of 2.3 to 4.4 nanometers. In this range, water is relatively transparent to X-rays, according to the statement. 

The "water window" soft X-rays can probe biological materials, and allow SXFEL to generate high intensity free electron laser pulses, which are one billion times brighter than those of synchrotron radiation light sources.

The progress is another breakthrough that the 532-meter-long free electron laser facility has made after realizing the amplification of light at wavelengths of 5.6, 3.5, 2.4 nanometers and 2.0 nanometers, which completed the full coverage of "water window" wavelengths in the middle of May. 

The construction of SXFEL started in November 2016, and the facility is expected to be in full operation at the end of 2021, said the statement. The SXFEL facility will start the user operation in 2022 and will be open to users around the world, it said. 

Global Times