The newly built High Energy Photon Source (HEPS) in China is expected to be open to global scientific researchers starting from 2025. The facility, with a budget of 4.8 billion yuan, located near Beijing, marks China's entry into the select group of nations possessing fourth-generation synchrotron light source technology.

In Huairou, a suburban district of Beijing, China's newly constructed high-energy facility is about to be inaugurated, spotlighting the world's brightest synchrotron radiation X-rays. This facility will fill a technological gap in Asia in this field and will place China among the world's leading pioneers who have such cutting-edge scientific research equipment.

Pedro Fernandes Tavares, the head of the accelerator department and a physicist from the MAX IV Laboratory in Lund, Sweden, stated: "This is an extremely advanced facility that will be a powerful support for outstanding scientific work." MAX IV is a model for synchrotron radiation facilities, and HEPS is a potential strong contender in terms of brightness.

About 50 kilometers from downtown Beijing in Huairou, researchers are busy fine-tuning the thousands of components inside the HEPS’s annular building, which can produce a powerful light source to resolve molecular and atomic structures in real-time. The HEPS team is set to complete the installation of the vacuum vessel system by the end of June, a critical component to ensure the light source maintains high brightness and stability.

With a storage ring of 1.36 kilometers, HEPS accelerates electrons to an energy of 6 gigaelectronvolts, thereby generating strong high-energy "hard" X-rays, capable of exploring samples at the nanoscale level. This device's time resolution is 10,000 times that of third-generation synchrotron accelerators, such as Shanghai's synchrotron radiation source, which is also among the most advanced such devices currently in use in China.

Tao Ye, a beamline scientist at the Institute of High Energy Physics (IHEP) of the Chinese Academy of Sciences, noted that with the introduction of new accelerators, researchers will be able to obtain measurement data in a few hundred nanoseconds instead of milliseconds as before. When HEPS opens to the scientific community in 2025, researchers will have a choice of 14 beamline stations for experiments in fields such as biomedicine, energy research, advanced materials, and condensed matter physics. It is expected that in the future, HEPS will support no less than 90 beamline stations. Tao Ye said, "This annular device will have a profound impact on all scientific fields except mathematics."

For the analysis of the atomic structure of proteins, researchers need to purify the molecules and form an ordered crystal structure suitable for X-ray imaging. Previous synchrotron accelerators required large-volume samples for research, and because small protein crystals are difficult to prepare, studies were nearly impossible. Tavares said that even the tiniest samples could be analyzed in detail using the strong, bright hard X-rays of HEPS.

The new type of synchrotron accelerator will also enable researchers to quickly complete experiments that previously took days. Tavares emphasizes, "It indeed is a true game-changer." There are about 70 synchrotron accelerators currently operating or under construction worldwide, and the completion of HEPS will help to improve the brightness and efficiency of devices in this field.

In the many synchrotron radiation sources around the world, only a few belong to the fourth generation, capable of producing the brightest and most focused beams of light. This includes the MAX IV Laboratory in Sweden, Sirius in Campinas, Brazil, the Extremely Brilliant Source at the European Synchrotron Radiation Facility in Grenoble, France, and the Advanced Photon Source in Illinois, USA. These are representative of the fourth-generation accelerator facilities.

The High Energy Photon Source (HEPS) is being built from scratch, rather than improving upon an existing facility. Chinese scientists, in pursuit of generating super-strong hard X-rays, require a new type of accelerator that is larger in scale than existing ones. Yu-Hui Li, a physicist at the Institute of High Energy Physics (IHEP) of the Chinese Academy of Sciences and the deputy manager of HEPS, states that to achieve this, HEPS has employed a magnetic array called a multi-bend achromat lattice which can generate a narrower and brighter X-ray beam compared to previous devices.

Harry Westfahl Jr, the operational director of the Brazilian Synchrotron Light Laboratory, points out that the electron beam produced by HEPS will be the narrowest in the world, capable of generating extremely powerful X-rays. Researchers will be able to gain more information from samples with the same level of radiation, aiding scientists to understand materials more deeply and develop new materials. Westfahl is also a member of the HEPS International Advisory Committee and anticipates that this high-resolution imaging technology will have a significant impact on scientific research.

Now, the critical task for researchers is to ensure that the beam stability reaches a usable level. Yu-Hui Li emphasizes that this is a complex process that requires precise tuning at every step: "No beam is perfect from the start."